2024年10月6日发(作者：堵书兰)
RT9986A
7-CH DC/DC Converter for DSC
General Description
The RT9986A is a complete power supply solution for
digital still cameras and other handheld devices. It includes
one synchronous step-up DC/DC converter with load
disconnect, one selectable synchronous step-up/step-
down DC/DC converter, two synchronous step-down DC/
DC converters, one synchronous high voltage step-up DC/
DC converter, one inverting DC/DC converter, and one
selectable synchronous high voltage step-up/current-
source for WLED. In addition, the RT9986A also includes
one RTC_LDO, one voltage detector, and one System
Reset. All power MOSFETs are integrated in the RT9986A.
The RT9986A is designed to fulfill the applications for DSC
as follows :
CH1 is a synchronous step-up output for motor or DSC
system I/O power
CH2 is a selectable synchronous step-up/step-down
output for motor or DSC system I/O power
CH3 and CH4 are synchronous step-down outputs for DSP
core and memory power supply
CH5 is a synchronous high voltage step-up output for CCD
bias power supply
CH6 is an inverting output for negative CCD bias power
supply
CH7 is a selectable synchronous high voltage step-up/
current source for driving WLED
The selectable step-up/step-down converter can be auto
selected by external component topology. For the
RT9986A, all 7-CHs have built in internal compensation.
The RT9986A also provides a transformerless inverting
converter for supplying CCD power. For the low voltage
synchronous step-up and step down converters, efficiency
can be up to 95%.
The RT9986A provides comprehensive protection features
including over current protection, thermal shutdown
protection, over voltage protection, overload protection,
and under voltage protection.
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Features
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CH2 Step-Up/Step-Down Auto-Selected by External
Topology
Preset On/Off Sequence of CH1, CH2, CH3, CH4
(1
→
3
→
4
→
2)
Preset On/Off Sequence of CH5, CH6 (5
→
6)
All Channels with Internal Compensation
All Power Switches Integrated
All Step-Up Converter with Load Disconnect
Step-Down DC/DC Converter
`
Up to 95% Efficiency
`
100% (max) Duty Cycle
Low Voltage Step-Up DC/DC Converter
`
Adjustable Output Voltage
`
Up to 95% Efficiency
WLED Driver
`
Auto-Selected by External Topology
`
Current Source Mode with 30mA DC Current
`
Step-Up Mode with LED Open Protection (OVP7)
`
Direct PWM Dimming Control
Fixed 2MHz Switching Frequency for CH1/2/3/4,
Fixed 1MHz Switching Frequency for CH5/6/7
Small 32-Lead WQFN Package
RoHS Compliant and Halogen Free
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Applications
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Digital Still Camera
PDA
Portable Devices
Marking Information
EZ= : Product Code
EZ=YM
DNN
YMDNN : Date Code
DS9986A-00 May
1
RT9986A
Ordering Information
RT9986A
Package Type
QW : WQFN-32L 4x4 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb
Free)
Note :
Richtek products are :
`
RoHS compliant and compatible with the current require-
Pin Configurations
(TOP VIEW)
E
N
5
6
L
X
1
P
V
D
D
1
B
A
T
L
X
6
P
V
D
D
2
L
X
2
E
N
1
2
3
4
32313
FB1
VREF
FB6
VOUT6
FB7
PVDD7
LX7
EN7
1
2
3
4
5
6
7
8
916
24
23
22
GND
33
21
20
19
18
17
FB2
SYSR
RTCPWR
VDDM
LX5
PVDD5
FB5
RST
`
Suitable for use in SnPb or Pb-free soldering processes.
2
L
X
4
P
V
D
D
4
F
B
4
V
C
H
K
V
N
E
G
F
B
3
P
V
D
D
3
L
X
3
ments of IPC/JEDEC J-STD-020.
WQFN-32L 4x4
DS9986A-00 May 2011
RT9986A
Typical Application Circuit
For 2AA
21
C1
1µF
V
BAT
29
C2
4.7µF
L5
10µH
V
BAT
C14
4.7µF
VDDM
PVDD1
FB1
RT9986A
30
1
C21
4.7pF
R1
470k
R2
88.7k
C4
10µF x 2
5V
BAT
20
LX5
LX1
31
L1
2.2µH
C3
4.7µF
V
BAT
15V
C13
10µF x 2
R9
287k
R10
26.1k
C12
27pF
19
PVDD5
PVDD2
27
24
C22
4.7pF
R3
470k
R4
150k
C6
10µF x 2
3.3V
18
FB5
FB2
4
VOUT6
D1
-7V
C18
10µF x 2
C15
1nF
R11
66.5k
R12
10.5k
C16
0.1µF
L6
10µH
28
LX6
LX2
26
L2
2.2µH
C5
4.7µF
C7
4.7µF
V
BAT
PVDD3
15
LX3
16
14
L3
2.2µH
5V
3
2
13
C17
0.1µF
FB6
2.5V
R5
768k
R6
360k
C8
10µF
VREF
VNEG
FB3
7
LX7
6
PVDD7
5
FB7
PVDD4
10
L4
2.2µH
C9
10µF
5V or V
BAT
D5
5V
LX4
9
FB4
11
1.8V
R7
470k
R8
374k
C10
10µF
8
EN7
ON
OFF
RTCPWR
R14
10k
3.3V
R15
100k
25
EN1234
32
EN56
12
VCHK
17
23
RST
RTCPWR
22
C11
Super Cap
33 (Exposed Pad)
GND
SYSR
DS9986A-00 May
3
RT9986A
For Li-ion
21
C1
1µF
V
BAT
29
C2
4.7µF
L5
10µH
V
BAT
C14
4.7µF
VDDM
PVDD1
FB1
RT9986A
LX1
31
L1
2.2µH
C4
4.7µF
V
BAT
30
1
C21
4.7pF
R1
470k
R2
88.7k
5V
C3
10µF x 2
BAT
20
LX5
15V
C13
10µF x 2
R9
287k
R10
26.1k
C12
27pF
19
PVDD5
LX2
26
24
L2
2.2µH
C22
10pF
R3
470k
R4
150k
C5
10µF
3.3V
18
FB5
FB2
4
VOUT6
D1
-7V
C18
10µF x 2
C15
1nF
R11
66.5k
R12
10.5k
C16
0.1µF
L6
10µH
28
LX6
PVDD2
27
C6
4.7µF
C7
4.7µF
V
BAT
PVDD3
15
LX3
16
14
L3
2.2µH
V
BAT
3
2
13
C17
0.1µF
L7
10µH
V
BAT
C19
1µF
D2
D3
D4
R13
10
C20
1µF
5
FB6
1.8V
R5
470k
R6
374k
C8
10µF
VREF
VNEG
FB3
PVDD4
10
7
LX7
LX4
9
6
PVDD7
FB4
11
FB7
RTCPWR
8
EN7
22
C11
Super Cap
33 (Exposed Pad)
L4
2.2µH
C9
4.7µF
5V or V
BAT
1V
R7
23.2k
R8
93.1k
C10
10µF
ON
OFF
RTCPWR
R14
10k
3.3V
R15
100k
25
EN1234
32
EN56
12
17
23
VCHK
RST
SYSR
GND
4
DS9986A-00 May 2011
RT9986A
Timing Diagram
Timing Diagram for CH1 to CH4
VDDM = Max
(BAT, PVDD1)
EN1234
CH1 VOUT
CH3 VOUT
CH4 VOUT
CH2 VOUT
User define
3.5ms
3.5ms
3.5ms
3.5ms
Wait until FB3 < 0.1V
Wait until FB4 < 0.1V
Wait until FB2 < 0.1V
CH5 and CH6 Power Sequence
The power on sequence is :
When EN56 goes high, CH5 will turn on first. After 10ms, CH6 will turn on.
The power off sequence is :
When EN56 goes low, CH6 will turn off first and VOUT6 will be internally pulled to GND.
When VOUT6 > −0.12V, CH6 discharging completes and then CH5 turns off. Finally, the whole IC shuts down.
Power On Sequence : CH5 HV Step-Up 15V
→
CH6 INV −7V
Power Off Sequence : CH6 INV −7V
→
CH5 HV Step-Up 15V
EN56
10ms
Constant Current
Pre-Charge.
10ms
Discharge by internal N-MOSFET
CH5
VOUT
CH6
VOUT
Wait until VOUT6 close to 0V
DS9986A-00 May
5
RT9986A
Functional Pin Description
Pin No.
1
2
3
4
Pin Name
FB1
VREF
FB6
VOUT6
Feedback Input Pin of CH1.
1.8V Reference Output Pin.
Feedback Input Pin of CH6.
Pin Function
Sense Input Pin of CH6 Inverting Output Node.
Feedback input pin of CH7 in step-up mode or current sink pin of CH7 in current
5 FB7
source mode.
6 PVDD7 Power Output Pin of CH7.
Switch Node of CH7 in Step-Up Mode. LX7 initial voltage determines CH7
7 LX7
operation mode.
8 EN7 Enable Pin of CH7 and PWM Dimming Signal Input Pin.
9
10
11
12
13
14
15
16
17
18
19
20
21
LX4
PVDD4
FB4
VCHK
VNEG
FB3
PVDD3
LX3
RST
FB5
PVDD5
LX5
VDDM
Switch Node of CH4.
Power Input Pin of CH4.
Feedback Input Pin of CH4.
Sense Pin of Voltage Detector.
Output Pin of Negative Regulator.
Feedback Input Pin of CH3.
Power Input Pin of CH3.
Switch Node of CH3.
Voltage Detector Open Drain Output Pin.
Feedback Input Pin of CH5.
Power Output Pin of CH5.
Switch Node of CH5.
IC Analog Power Pin.
Internal Control Circuit Power Pin. That must connect to a bypass capacitor for
22 RTCPWR
better noise rejection.
23 SYSR System Reset Open-Drain Output Pin.
24
25
26
FB2
EN1234
LX2
Feedback Input Pin of CH2.
Enable Pin of CH1, CH2, CH3, CH4.
Switch Node of CH2.
Power Input Pin for Step-Down of CH2.
27 PVDD2
Power Output Pin for Step-Up of CH2.
28 LX6 Switch Node of CH6.
29 BAT Battery Power Pin.
30
31
32
PVDD1
LX1
EN56
Power Output Pin of CH1.
Switch Node of CH1.
Enable Pin of CH5, CH6.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum thermal dissipation.
33 (Exposed pad) GND
6
DS9986A-00 May 2011
RT9986A
Function Block Diagram
VDDM
PVDD5
Body
Diode
Control
BAT
VDDM
BAT
LX5
UVLOUVLO
CH5
C-Mode
Step-Up
PWM
Soft-Start
VDDI
VDDM
PVDD1
Body
Diode
Control
FB5
1.25V
REF
-
+
BAT
VDDM
CH1
C-Mode
Step-Up
BAT
LX1
CH6
Inverting
LX6
VNEG
-
+
0.8V
REF
VDDM
FB1
VOUT6
FB6
1.8V
REF
VDDM
CH7 C-Mode
Step-Up or
Current Source
+
PWM Dimming
+
Mode Selector
-
+
PVDD2
Body
Diode
Control
BAT
LX2
+
0.6V
REF
-
CH2
C-Mode
Step-Up or
Step-Down
VREF
PVDD7
BAT
LX7
Body
Diode
Control
-
+
0.8V
REF
VDDM
FB2
PVDD3
FB7
0.25V
REF
30mA(max.)
CH3
C-Mode
Step-Down
LX3
EN7
EN1234
EN56
Power On/Off
Sequence Control
Logic Block
VDDM
RTCPWR
VCHK
RST
Voltage
Detector
CH4
C-Mode
Step-Down
-
+
0.8V
REF
PVDD4
FB3
LX4
VDDM
SYSR
SYS_Reset
GND
FB2
VDDI
-
+
0.8V
REF
FB4
RTC_LDO
W/ Body Diode
Control
RTCPWR
DS9986A-00 May
7
RT9986A
Absolute Maximum Ratings
(Note 1)
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Supply Input Voltage, VDDM, BAT---------------------------------------------------------------------−0.3V to 6V
VOUT6--------------------------------------------------------------------------------------------------------−10V to 0.3V
LX1, LX2, LX3, LX4-----------------------------------------------------------------------------------------−0.3V to 6V
PVDD5, LX5-------------------------------------------------------------------------------------------------−0.3V to 24V
PVDD7, LX7-------------------------------------------------------------------------------------------------−0.3V to 17V
LX6-------------------------------------------------------------------------------------------------------------(BAT − 14V) to (BAT + 0.3V)
Other Pins----------------------------------------------------------------------------------------------------−0.3V to 6V
Power Dissipation, P
D
@ T
A
= 25°C
WQFN 32L 4x4----------------------------------------------------------------------------------------------3.590W
Package Thermal Resistance (Note 2)
WQFN 32L 4x4, θ
JA
----------------------------------------------------------------------------------------27.8°C/W
WQFN 32L 4x4, θ
JC
----------------------------------------------------------------------------------------7°C/W
Junction Temperature--------------------------------------------------------------------------------------150°C
Lead Temperature (Soldering, 10 sec.)----------------------------------------------------------------260°C
Storage Temperature Range-----------------------------------------------------------------------------−65°C to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Mode)-------------------------------------------------------------------------------2kV
MM (Machine Mode)---------------------------------------------------------------------------------------200V
Recommended Operating Conditions
(Note 4)
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VDDM---------------------------------------------------------------------------------------------------------2.7V to 5.8V
Junction Temperature Range-----------------------------------------------------------------------------
−
40°C to 125°C
Ambient Temperature Range-----------------------------------------------------------------------------
−
40°C to 85°C
Electrical Characteristics
Supply Input Voltage
BAT Startup Voltage
BAT UVLO Threshold
BAT UVLO Hysteresis
VDDM OVP Threshold
VDDM OVP Hysteresis
VDDM UVLO Threshold
VDDM UVLO Hysteresis
Supply
Current
(V
DDM
= V
BAT
= 3.3V, T
A
= 25°C, unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
V
ST
BAT Falling
VDDM Rising
VDDM Rising
1.5 -- -- V
-- 1.3 -- V
-- 0.2 -- V
5.85
--
2.2
--
6 6.15 V
−0.25 -- V
2.4
0.3
2.6
--
V
V
Shutdown Supply Current
(I
BAT
+ I
VDDM
)
CH1 Synchronous Step-Up Supply
Current into VDDM
CH2 Synchronous Step-Up or
Step-Down Supply Current into VDDM
I
OFF
All EN pins = 0, V
BAT
= 3.3V --
--
--
--
10
--
--
--
20
800
800
800
μA
μA
μA
μA
I
Q1
Non switching, V
EN1234
= 3.3V
I
Q2
Non switching, V
EN1234
= 3.3V
V
EN1234
= 3.3V
CH3 Synchronous Step-Down Supply
I
Q3
Current into VDDM
8
To be continued
DS9986A-00 May 2011
RT9986A
Parameter Symbol Test Conditions Min Typ Max Unit
CH4 Synchronous Step-Down
Non switching, V
EN1234
= 3.3V -- -- 800 μA
I
Q4
Supply Current into VDDM
CH5 Synchronous Step-Up Supply
Non switching, V
EN56
= 3.3V -- -- 800 μA
I
Q5
Current into VDDM
CH6 (Inverting)
I
Q6
Non switching, V
EN56
= 3.3V -- -- 800 μA
Supply Current into VDDM
CH7 (WLED) in Step-Up Mode
Non switching, V
EN7
= 3.3V -- -- 800 μA
I
Q7b
Supply Current into VDDM
CH7 (WLED) in Current Source
V
EN7
= 3.3V, V
LX7
= 0V -- -- 800 μA
I
Q7c
Mode Supply Current into VDDM
Oscillator
CH1, 2, 3, 4 Operation Frequency
CH5, 6, 7 Operation Frequency
CH2 Maximum Duty Cycle (Step-Up)
CH2 Maximum Duty Cycle
(Step-Down)
CH3 Maximum Duty Cycle
(Step-Down)
CH4 Maximum Duty Cycle
(Step-Down)
CH5 Maximum Duty Cycle (Step-Up)
f
OSC
f
OSC2
CH7 in Step-Up mode
V
FB1
= 0.75V
V
FB2
= 0.75V
V
FB2
= 0.75V
V
FB3
= 0.75V
V
FB4
= 0.75V
V
FB5
= 1.15V
V
FB6
= 0.7V
V
FB7
= 0.15V
1800 2000 2200 kHz
900
80
80
--
--
--
91
91
91
1000
83
83
--
--
--
93
93
93
1100
86
86
100
100
100
97
97
97
kHz
%
%
%
%
%
%
%
%
CH1 Maximum Duty Cycle (Step-Up)
CH6 Maximum Duty Cycle (Inverting)
CH7 Maximum Duty Cycle (Step-Up)
Feedback, Regulation Voltage
Feedback Regulation Voltage @
FB1, FB2, FB3, FB4
Feedback Regulation Voltage @ FB5
Feedback Regulation Voltage @ FB6
(Inverting)
Feedback Regulation Voltage @ FB7
Output Current (CS Mode)
Dropout Voltage @ FB7 (CS Mode)
VREF Output Voltage
VREF Load Regulation
PowerSwitch
V
FB5
V
FB6
V
FB7
V
LX7
= 0V
0.788 0.8 0.812 V
1.237 1.25 1.263 V
0.59 0.6 0.61 V
0.237 0.25 0.263 V
28.5
--
30
--
31.5
0.3
mA
V
V
REF
1.782 1.8 1.818 V
0μA < I
REF
< 200μA -- -- 10 mV
-- 200 300 P-MOSFET V
PVDD1
= 3.3V
R
DS(ON)1
N-MOSFET V
PVDD1
= 3.3V
CH1 Current Limitation (Step-Up) I
LIM1
P-MOSFET V
PVDD2
= 3.3V
CH2 On Resistance R
DS(ON)2
N-MOSFET V
PVDD2
= 3.3V
CH1 On-Resistance
CH2 Current Limitation (Step-Down) I
LIM2_D
CH2 Current Limitation (Step-Up)
DS9986A-00 May 2011
mΩ
-- 150 250
2.2 3 4 A
-- 200 300
mΩ
-- 150 250
1.2 1.6 2 A
2.2 3 4 A
To be continued
9
I
LIM2_U
RT9986A
CH3 On Resistance
P-MOSFET V
PVDD3
= 3.3V
R
DS(ON)3
N-MOSFET V
PVDD3
= 3.3V
P-MOSFET V
PVDD4
= 3.3V
R
DS(ON)4
N-MOSFET V
PVDD4
= 3.3V
--
--
--
--
300
300
300
300
400
400
400
400
mΩ
Parameter Symbol Test Conditions Min Typ Max Unit
CH3 Current Limitation (Step-Down) I
LIM3
CH4 On Resistance
1.2 1.6 2 A
mΩ
CH4 Current Limitation (Step-Down) I
LIM4
P-MOSFET V
PVDD5
= 16V
R
DS(ON)5
N-MOSFET V
PVDD5
= 3.3V
CH5 Current Limitation of
I
LIM5
N-MOSFET
CH6 On Resistance of P-MOSFET R
DS(ON)6
CH6 Current Limitation of
I
LIM6
P-MOSFET
P-MOSFET V
PVDD7
= 10V
CH7 On Resistance R
DS(ON)7
N-MOSFET V
PVDD7
= 3.3V
CH7 Current Limitation of
I
LIM7
N-MOSFET
Protection
Over Voltage Protection of PVDD1
and PVDD2
Over Voltage Protection of PVDD5
CH5 On Resistance
1.2 1.6 2 A
-- 0.8 1
-- 0.6 0.8
Ω
0.9 1.2 1.6 A
-- 0.5 0.7 Ω
1 1.5 2 A
-- 3 --
Ω
-- 0.9 1.1
0.6 0.8 1 A
5.85 6 6.15 V
20
--
21 22 V
Over Voltage Protection of VOUT6
Over Voltage Protection of PVDD7
(Step-Up Mode)
CH1, CH2 Step-Up Under Voltage
Protection of PVDD1 and PVDD2
CH1/2/3/4 Under Voltage Protection
CH5 Under Voltage Protection
CH6 Under Voltage Protection
CH1/2/3/4 Over Load Protection
CH5 Over Load Protection
CH6 Over Load Protection
Protection Fault Delay
Control
−13 -- V
At V
FBx
< 0.4V after soft-start
ends
At V
FB5
< 0.6V after soft-start
ends
At V
FB6
> 1.2V after soft-start
end
At V
FBx
< 0.7V after fault delay
(100ms)
At V
FB5
< 1.1V after fault delay
(100ms)
At V
FB6
> 0.74V after fault
delay (100ms)
High to Select Step-Up Mode
Low to Select CS Mode
14.3 15 16 V
V
BAT
-- V --
−0.8V
0.35 0.4 0.45 V
0.5 0.6 0.7 V
1.1 1.2 1.3 V
0.65 0.7 0.75 V
1.05 1.1 1.15 V
0.69 0.74 0.79 V
--
1.3
--
1
--
--
100
--
--
--
0.25
2
--
--
0.4
--
--
6
ms
Logic-High
EN1234, EN56, EN7
Input Threshold Voltage
Logic-Low
LX7 Input Threshold
Voltage
Logic-High
Logic-Low
V
V
μA EN1234, EN56, EN7 Sink Current
EN7 Low Time for Shutdown
10
t
SHDN
-- 32 -- ms
To be continued
DS9986A-00 May 2011
RT9986A
Thermal Protection
Thermal Shutdown
Thermal Shutdown Hysteresis
System Reset
SYSR, FB2 Regulation Threshold
SYSR, FB2 Hysteresis
SYSR Rising Delay Time
SYSR Sink Capability
Voltage Detector
Voltage Detector Reset Threshold
(VCHK
<
Threshold Æ RST = L)
Voltage Detector Reset Hysteresis
Standby Current
RST Rising Delay Time
RST Sink Capability
RTC LDO
for SYSR to go low
V
SYSR
= 0.5V
0.709 0.72 0.731
--
--
4
40
10
--
--
--
--
V
mV
ms
mA
T
SD
ΔT
SD
125 160 -- °C
-- 20 -- °C
Parameter Symbol Test Conditions Min Typ Max Unit
VCHK Falling
V
VCHK
= 3V
V
RST
= 0.5V, V
VCHK
= 1.5V
V
DDM
= 4.2V
I
OUT
= 0mA
V
DDM
= 4.2V
I
OUT
= 50mA
I
OUT
= 10mA
I
OUT
= 3mA
1.57 1.6 1.63 V
--
--
4
--
3.1
60
--
--
--
16
2
--
5
3.2
130
--
--
--
--
4
--
8
3.3
200
1000
150
60
mV
mV
μA
mA
μA
V
mA
35 55 75 ms
Standby Current
Regulated Output Voltage @
RTCPWR
Max Output Current (Current Limit)
Dropout Voltage
Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for
stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational
sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may
remain possibility to affect device reliability.
Note 2. θ
JA
is measured in natural convection at T
A
= 25°C on a high-effective thermal conductivity four-layer test board of JEDEC
51-7 thermal measurement standard. The measurement case position of θ
JC
is on the exposed pad of the package.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
DS9986A-00 May
11
RT9986A
Typical Operating Characteristics
CH1 Step-Up Efficiency vs. Output Current
100
90
80
CH1 Step-Up Efficiency vs. Output Current
100
90
E
f
f
i
c
i
e
n
c
y
(
%
)
60
50
40
30
20
10
0
10
E
f
f
i
c
i
e
n
c
y
(
%
)
70
V
BAT
= 4.5V
V
BAT
= 4.2V
V
BAT
= 3.9V
V
BAT
= 3.6V
V
BAT
= 3.3V
V
BAT
= 3V
80
70
60
50
40
30
20
V
BAT
= 3V
V
BAT
= 2.7V
V
BAT
= 2.5V
V
BAT
= 2.2V
V
BAT
= 2V
V
BAT
= 1.8V
V
OUT
= 5V, L = 2.2μH, C
OUT
= 10μF x 2
1001000
10
0
10
V
OUT
= 3.3V, L = 2.2μH, C
OUT
= 10μF x 2
1001000
Output Current (mA)Output Current (mA)
CH2 Step-Up Efficiency vs. Output Current
100
90
80
CH2 Step-Down Efficiency vs. Output Current
100
90
E
f
f
i
c
i
e
n
c
y
(
%
)
60
50
40
30
20
10
0
10
E
f
f
i
c
i
e
n
c
y
(
%
)
70
V
BAT
= 3.6V
V
BAT
= 3.3V
V
BAT
= 3V
V
BAT
= 2.7V
V
BAT
= 2.5V
V
BAT
= 2.2V
V
BAT
= 1.8V
80
70
60
50
40
30
20
V
BAT
= 3.4V
V
BAT
= 3.7V
V
BAT
= 3.9V
V
BAT
= 4.2V
V
BAT
= 4.5V
V
BAT
= 5V
V
OUT
= 5V, L = 2.2μH, C
OUT
= 10μF x 2
1001000
10
0
10
V
OUT
= 3.3V, L = 2.2μH, C
OUT
= 10μF
1001000
Output Current (mA)Output Current (mA)
CH 3 Step-Down Efficiency vs. Output Current
100
90
80
CH4 Step-Down Efficiency vs. Output Current
100
90
E
f
f
i
c
i
e
n
c
y
(
%
)
E
f
f
i
c
i
e
n
c
y
(
%
)
70
60
50
40
30
20
10
0
10
V
BAT
= 2.7V
V
BAT
= 3V
V
BAT
= 3.3V
V
BAT
= 3.6V
V
BAT
= 3.9V
V
BAT
= 4.2V
V
BAT
= 4.5V
80
70
60
50
40
30
20
V
BAT
= 1.8V
V
BAT
= 2.5V
V
BAT
= 3V
V
BAT
= 3.3V
V
BAT
= 3.6V
V
BAT
= 4.2V
V
BAT
= 4.5V
V
OUT
= 1.8V, L = 2.2μH, C
OUT
= 10μF
1001000
10
0
10
V
OUT
= 1V, L = 2.2μH, C
OUT
= 10μF
1001000
Output Current (mA)Output Current (mA)
12
DS9986A-00 May 2011
RT9986A
CH5 Step-Up Efficiency vs. Output Current
100
90
CH6 Inverting Efficiency vs. Output Current
100
90
E
f
f
i
c
i
e
n
c
y
(
%
)
70
60
50
40
30
20
10
0
0.001
V
BAT
= 4.5V
V
BAT
= 4.2V
V
BAT
= 3.9V
V
BAT
= 3.6V
V
BAT
= 3.3V
V
BAT
= 3V
V
BAT
= 2.7V
V
BAT
= 2.5V
V
BAT
= 2.2V
V
BAT
= 2V
V
OUT
= 16V, L = 10μH, C
OUT
= 10μF x 2
0.010.1
I
n
v
e
r
t
i
n
g
E
f
f
i
c
i
e
n
c
y
(
%
)
8080
70
60
50
40
30
20
10
0
1
V
BAT
= 4.2V
V
BAT
= 3.9V
V
BAT
= 3.6V
V
BAT
= 3.3V
V
BAT
= 3V
V
BAT
= 2.7V
V
BAT
= 4.5V
V
BAT
= 2.5V
V
BAT
= 2.2V
V
BAT
= 2V
V
OUT
= −8V, L = 10μH, C
OUT
= 10μF x 2
10100
Output Current (A)Output Current (mA)
CH7 Efficiency vs. Input Voltage
100
90
80
CH1 Step-Up Output Voltage vs. Output Current
5.20
5.15
E
f
f
i
c
i
e
n
c
y
(
%
)
70
60
50
40
30
20
10
0
1.82.12.42.733.33.63.94.24.5
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
5.10
5.05
5.00
4.95
4.90
4.85
V
BAT
= 3V
V
BAT
= 4.5V
I
OUT
= 25mA, L = 10μH, C
OUT
= 1μF
4.80
0
V
OUT
= 5V
500600
Input Voltage (V)Output Current (mA)
CH1 Step-Up Output Voltage vs. Output Current
3.35
CH2 Step-Up Output Voltage vs. Output Current
5.10
3.33
V
BAT
= 1.8V
5.08
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
V
BAT
= 3V
5.06
3.31
V
BAT
= 3.2V
V
BAT
= 4.2V
5.04
3.29
3.27
5.02
V
OUT
= 3.3V
3.25
0500600
5.00
0
V
OUT
= 5V
500600
Output Current (mA)Output Current (mA)
DS9986A-00 May
13
RT9986A
CH2 Step-Down Output Voltage vs. Output Current
3.36
CH3 Step-Down Output Voltage vs. Output Current
1.830
1.825
3.34
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
3.32
V
BAT
= 4.5V
V
BAT
= 5V
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
1.820
1.815
1.810
1.805
3.30
V
BAT
= 3V
V
BAT
= 4.5V
3.28
V
OUT
= 3.3V
3.26
0500600
1.800
0
V
OUT
= 1.8V
500600
Output Current (mA)Output Current (mA)
CH4 Step-Down Output Voltage vs. Output Current
1.006
1.004
CH5 Step-Up Output Voltage vs. Output Current
16.3
16.2
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
1.002
1.000
0.998
0.996
0.994
0.992
V
BAT
= 4.5V
V
BAT
= 2.7V
V
BA
T
= 3V
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
16.1
V
BAT
= 3.4V
V
BAT
= 4.5V
16.0
15.9
V
OUT
= 1V
15.8
400500600
0204060
V
OUT
= 16V
80100
Output Current (mA)
Output Current (mA)
CH6 Inverting Efficiency vs. Output Current
-8.190
Power On Sequence
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
-8.195
V
BAT
= 2.7V
V
BAT
= 3.4V
V
BAT
= 4.5V
V
OUT_CH1
(5V/Div)
V
OUT_CH2
(2V/Div)
V
OUT_CH3
(2V/Div)
V
OUT_CH4
(2V/Div)
Time (2.5ms/Div)
-8.200
-8.205
V
OUT
= −8V
-8.210
V
BAT
=
3.7V
Output Current (mA)
14
DS9986A-00 May 2011
RT9986A
Power Off Sequence
V
OUT_CH1
(5V/Div)
V
OUT_CH2
(2V/Div)
V
OUT_CH3
(2V/Div)
V
OUT_CH4
(2V/Div)
Time (1ms/Div)
Power On Sequence
V
OUT_CH5
(10V/Div)
V
OUT_CH6
(5V/Div)
V
BAT
=
3.7VV
BAT
=
3.7V
Time (5ms/Div)
Power Off SequenceCH1 Output Voltage Ripple
V
OUT_CH5
(10V/Div)
V
OUT_CH6
(5V/Div)
LX1
(2V/Div)
V
OUT_CH1_ac
(10mV/Div)
V
BAT
=
3.7V
V
BAT
= 3.7V, V
OUT
= 5V,
I
OUT
= 400mA, L = 2.2μH, C
OUT
= 10μF x 2
Time (2.5ms/Div)Time (500ns/Div)
CH2 Output Voltage RippleCH3 Output Voltage Ripple
LX2
(2V/Div)
LX3
(2V/Div)
V
OUT_CH2_ac
(2mV/Div)
V
BAT
= 3.7V, V
OUT
= 3.3V,
I
OUT
= 400mA, L = 2.2μH, C
OUT
= 10μF
V
OUT_CH3_ac
(5mV/Div)
V
BAT
= 3.7V, V
OUT
= 1.8V,
I
OUT
= 400mA, L = 2.2μH, C
OUT
= 10μF
Time (500ns/Div)Time (500ns/Div)
DS9986A-00 May
15
RT9986A
CH4 Output Voltage Ripple
CH5 Output Voltage Ripple
LX4
(2V/Div)
LX5
(10V/Div)
V
OUT_CH4_ac
(5mV/Div)
V
BAT
= 3.7V, V
OUT
= 1V,
I
OUT
= 400mA, L = 2.2μH, C
OUT
= 10μF
V
OUT_CH5_ac
(10mV/Div)
V
BAT
= 3.7V, V
OUT
= 16V,
I
OUT
= 30mA, L = 10μH, C
OUT
= 10μF
Time (500ns/Div)Time (1μs/Div)
CH6 Output Voltage RippleCH1 Load Transient Response
LX6
(10V/Div)
I
OUT
(100mA/Div)
V
OUT_CH1_ac
(100mV/Div)
V
BAT
= 3.7V, V
OUT
= −8V,
I
OUT
= 50mA, L = 10μH, C
OUT
= 10μF x 2
V
BAT
= 3.7V, V
OUT
= 5V,
I
OUT
= 0 to 300mA, L = 2.2μH, C
OUT
= 10μF x 2
V
OUT_CH6_ac
(10mV/Div)
Time (1μs/Div)Time (1ms/Div)
CH2 Load Transient ResponseCH3 Load Transient Response
I
OUT
(100mA/Div)
V
OUT_CH2_ac
(50mV/Div)
V
BAT
= 3.7V, V
OUT
= 3.3V,
I
OUT
= 0 to 300mA, L = 2.2μH, C
OUT
= 10μF
I
OUT
(100mA/Div)
V
OUT_CH3_ac
(50mV/Div)
V
BAT
= 3.7V, V
OUT
= 1.8V,
I
OUT
= 0 to 300mA, L = 2.2μH, C
OUT
= 10μF
Time (1ms/Div)Time (1ms/Div)
16
DS9986A-00 May 2011
RT9986A
CH4 Load Transient Response
CH5 Load Transient Response
I
OUT
(100mA/Div)
V
OUT_CH4_ac
(20mV/Div)
V
BAT
= 3.7V, V
OUT
= 1V,
I
OUT
= 0 to 300mA, L = 2.2μH, C
OUT
= 10μF
I
OUT
(20mA/Div)
V
OUT_CH5_ac
(50mV/Div)
V
BAT
= 3.7V, V
OUT
= 16V,
I
OUT
= 10 to 30mA, C
OUT
= 10μF
Time (1ms/Div)Time (1ms/Div)
CH6 Load Transient Response
I
OUT
(20mA/Div)
V
OUT_CH6_ac
(20mV/Div)
V
BAT
= 3.7V, V
OUT
= −8V,
I
OUT
= 15 to 50mA, C
OUT
= 10μF x 2
Time (1ms/Div)
DS9986A-00 May
17
RT9986A
Application Information
The RT9986A is a multiple output power supply system
for digital still cameras and other small handheld devices.
It includes six DC/DC converters as well as one WLED
driver, one RTC LDO, one voltage detector, and one
system reset. The WLED works in either current source
mode or step-up mode.
CH1 : Step-up synchronous current mode DC/DC converter
with internal power MOSFETs and compensation network.
The P-MOSFET body can be controlled to disconnect the
load.
CH2 : Step-up or step-down synchronous current mode
DC/DC converter with internal power MOSFETs and
compensation network. External circuit topology
automatically determines whether CH2 is in step-up or
step-down mode. During step-up mode, the P-MOSFET
body can be controlled to disconnect the load if input
voltage is not higher than the V
BAT
.
CH3 : Step-down synchronous current mode DC/DC
converter with internal power MOSFETs and
compensation network.
CH4 : Step-down synchronous current mode DC/DC
converter with internal power MOSFETs and
compensation network.
CH5 : Step-up synchronous current mode DC/DC converter
with internal power MOSFET and compensation network.
The P-MOSFET body can be controlled to disconnect the
load.
CH6 : Asynchronous inverting current mode DC/DC
converter with internal power MOSFET and compensation
network.
CH7 : A WLED driver operating in either current source
mode or synchronous step-up mode with internal power
MOSFET and compensation network. Operation mode is
determined by LX7 initial voltage The P-MOSFET body in
step-up mode can be controlled to disconnect the load
disconnected.
CH1 to CH4 operate in PWM mode with 2MHz, while
CH5 to CH7 operate in PWM mode with 1MHz switching
frequency.
RTC_LDO : A 3.1V output LDO with low quiescent current
and high output voltage accuracy.
18
DS9986A-00 May 2011
System Reset : Accurate voltage detector for checking
CH2 output voltage status.
Voltage Detector : A general, low quiescent current voltage
detector for monitoring status of a node voltage such as
for RTC_LDO output or others.
CH1 : Synchronous Step-Up DC/DC Converter
CH1 is a synchronous step-up converter which can be
used for motor power. The converter operates at fixed
frequency and PWM current mode. The converter
integrates internal MOSFETs, compensation network and
synchronous rectifier for up to 95% efficiency.
The output voltage can be set by the following equation :
V
OUT_CH1
= (1 + R1 / R2) x V
FB1
where V
FB1
is 0.8V typically.
CH2 : Synchronous Step-Up / Step-Down
Selectable DC/DC Converter
CH2 is a synchronous step-up / step-down auto-select
converter, typically for system I/O power. In either step-
up or step-down, the converter operates in fixed frequency
PWM mode, Continuous Current Mode (CCM), and
Discontinuous Current Mode (DCM) with internal
MOSFETs, compensation network and synchronous
rectifiers for up to 95% efficiency.
Step-Up :
In step-up mode, CH2 also disconnects the load from its
input power node and discharges output node of CH2 when
it is turned off.
Step-Down :
In step-down mode, the CH2 converter can be operated
at 100% maximum duty cycle to extend the input
operating voltage range. When the input voltage is close
to the output voltage, the converter enters low dropout
mode.
The output voltage can be set by the following equation :
V
OUT_CH2
= (1 + R3 / R4) x V
FB2
where V
FB2
is 0.8V typically.
RT9986A
CH3 : Synchronous Step-Down DC/DC Converter
CH3 operates in fixed frequency PWM mode with
integrated internal MOSFETs and compensation network.
The CH3 step-down converter can be operated at 100%
maximum duty cycle to extend battery operating voltage
range. When the input voltage is close to the output
voltage, the converter enters low dropout mode with low
output ripple.
The output voltage can be set by the following equation :
V
OUT_CH3
= (1 + R5 / R6) x V
FB3
where V
FB3
is 0.8V typically.
CH4 : Synchronous Step-Down DC/DC Converter
CH4 operates at fixed frequency PWM mode with
integrated internal MOSFETs and compensation network.
The CH4 step-down converter can be operated at 100%
maximum duty cycle to extend battery operating voltage
range. When the input voltage is close to the output
voltage, the converter enters low dropout mode with low
output ripple.
The output voltage can be set by the following equation:
V
OUT_CH4
= (1 + R7 / R8) x V
FB4
where V
FB4
is 0.8V typically.
CH5 : Synchronous Step-Up DC/DC Converter
CH5 is a high voltage synchronous step-up converter for
CCD positive power. The converter operates at fixed
frequency PWM mode, CCM, DCM, and PSM (pulse skip
mode) with integrated internal MOSFETs, compensation
network and load disconnect function.
The output voltage can be set by the following equation:
V
OUT_CH5
= (1 + R9 / R10) x V
FB5
where V
FB5
is 1.25V typically.
CH6 : INV DC/DC Converter
This converter integrates an internal P-MOSFET with
internal compensation and needs an external Schottky
diode to provide CCD negative power supply.
The output voltage can be set by the following equation :
V
OUT_CH6
= −(R11 / R12) x (1.2V) + 0.6V
where R11 and R12 are the feedback resistors connected
DS9986A-00 May 2011
to FB6, 1.2V equals to (V
REF
− V
FB6
) and 0.6V is V
FB6
typical.
Reference Voltage
The RT9986A provides a precise 1.8V reference voltage,
V
REF
, with souring capability of 100µA. Connect a 0.1µF
ceramic capacitor from the VREF pin to GND. Reference
voltage is enabled by pulling EN6 to logic-high.
Furthermore, this reference voltage is internally pulled to
GND at shutdown.
CH7 : WLED Driver
CH7 is a WLED driver that can operate in either current
source mode or synchronous step-up mode, as determined
by LX7
'
s initial voltage level.
Table 1. CH7 WLED setting
CH7 Operating Mode
Current Source
Synchronous Step-Up
LX7
< 0.25V
> 1V
When CH7 works in current source mode, it sinks an
accurate LED current modulated by EN7 high duty such
that it is easily dimmed from 0mA to 30mA. If CH7 works
in synchronous step-up mode, it integrates synchronous
step-up mode with an internal MOSFET and internal
compensation to output a voltage up to 15V. The LED
current is set via an external resistor and controlled via
the PWM duty on the EN7 pin. Regardless of the mode,
holding EN7 low for more than 32ms will turn off CH7.
In addition, CH7 will be turned on until the CH2 soft-start
is finished.
CH7 WLED Current Dimming Control
If CH7 is in synchronous step-up mode, the WLED current
is set by an external resistor. If CH7 is in current source
mode, the sink current into the FB7 pin is 30mA typically
when EN7 is high. Regardless of the mode, dimming is
always controlled by the duty of pulse-width modulated
signal on the EN7 pin. The PWM dimming duty must be
over 10%.
The average current through WLED can be set by the
following equations :
I
LED
(mA) = [250mV / R (W)] x Duty (%) (for step-up mode)
or I
LED
(mA) = 30mA x Duty (%) (for current source mode)
19
RT9986A
R is the current sense resistor from FB7 to GND and Duty
is the duty of the PWM dimming signal into EN7 pin.
Dimming frequency range is from 1kHz to 100kHz but
2kHz to 20kHz should be avoided to prevent distraction
from audio noise.
VDDM Bootstrap
To support bootstrap function, the RT9986A includes a
power selection circuit which selects between BAT and
PVDD1 to create the internal node voltage VDDI and VDDM.
VDDM is the power of all the RT9986A control circuits
and must be connected to an external decoupling capacitor
by way of the VDDM pin. The VDDI is the power input of
the RTC LDO. The output PVDD1 of CH1 can bootstrap
VDDM and VDDI. The RT9986A includes UVLO circuits
to monitor VDDM and BAT voltage status.
RTC LDO
The RT9986A provides a 3.1V output LDO for real time
clock. The LDO features low quiescent current (5µA) and
high output voltage accuracy. This LDO is always on, even
when the system is shut down. For better stability, is it
recommended to connect a 0.1µF to the RTCPWR pin.
The RTC LDO includes pass transistor body diode control
to avoid the RTCPWR node from back-charging into the
input node VDDI.
System Reset
The RT9986A also provides a system voltage detector to
monitor system power status via FB2. If FB2 level is lower
than 90% setting, the open drain output pin SYSR will
pull down. When FB2 level is higher than 95% setting,
the SYSR pin will go high after 10ms.
Voltage Detector
The RT9986A provides a voltage detector to detect the
voltage status at the VCHK pin. The input power of the
voltage detector is RTCPWR and the detector is always
on. 55ms after VCHK voltage > 1.616V, the open drain
output /RST will be pulled high. If VCHK < 1.6V, the /RST
pin will be pulled down to GND immediately.
Power On/Off Sequence for CH1 to CH4
EN1234 will turn on/off CH1 to CH4 in preset sequence.
CH1 to CH4 Power On Sequence is:
20
When EN1234 goes high, CH1 will turn on first. 3.5ms
after CH1 is turned on, CH3 will turn on. 3.5ms after CH3
is turned on, CH4 will turn on. 3.5ms after CH4 is turned
on, CH2 will turn on.
CH1 to CH4 Power-Off Sequence is :
When EN1234 goes low, CH2 will turn off first and internally
discharge output.
When FB2 < 0.1V, CH4 will turn off and also internally
discharge output via the LX4 pin. When FB4 < 0.1V, CH3
will turn off and internally discharge output via the LX3
pin. Likewise, when FB3 < 0.1V, CH1 will turn off and
discharge output. After FB1 < 0.1V, CH1 to 4 shutdown
sequence will be completed.
Thermal Considerations
For continuous operation, do not exceed absolute
maximum junction temperature. The maximum power
dissipation depends on the thermal resistance of the IC
package, PCB layout, rate of surrounding airflow, and
difference between junction and ambient temperature. The
maximum power dissipation can be calculated by the
following formula :
P
D(MAX)
= (T
J(MAX)
− T
A
) / θ
JA
where T
J(MAX)
is the maximum junction temperature, T
A
is
the ambient temperature, and θ
JA
is the junction to ambient
thermal resistance.
For recommended operating condition specifications of
the RT9986A, the maximum junction temperature is 125°C
and T
A
is the ambient temperature. The junction to ambient
thermal resistance, θ
JA
, is layout dependent. For WQFN-
32L 4x4 packages, the thermal resistance, θ
JA
, is 27.8°C/
W on a standard JEDEC 51-7 four-layer thermal test board.
The maximum power dissipation at T
A
= 25°C can be
calculated by the following formula :
P
D(MAX)
= (125°C − 25°C) / (27.8°C/W) = 3.59W for
WQFN-32L 4x4 package
The maximum power dissipation depends on the operating
ambient temperature for fixed T
J(MAX)
and thermal
resistance,θ
JA
. For the RT9986A package, the derating
curve in Figure 1 allows the designer to see the effect of
rising ambient temperature on the maximum power
dissipation.
DS9986A-00 May 2011
RT9986A
4.0
M
a
x
i
m
u
m
P
o
w
e
r
D
i
s
s
i
p
a
t
i
o
n
(
W
)
3.6
3.2
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0.0
0255075
Four-Layers PCB
Layout Consideration
For the best performance of the RT9986A, the following
PCB layout guidelines must be strictly followed.
}
Place the input and output capacitors as close as
possible to the input and output pins respectively for
good filtering.
Keep the main power traces as wide and short as
possible.
The switching node area connected to LX and inductor
should be minimized for lower EMI.
Place the feedback components as close as possible
to the FB pin and keep these components away from
the noisy devices.
Connect the GND and Exposed Pad to a strong ground
plane for maximum thermal dissipation and noise
protection.
V
OUT_CH2
C5
GND
R3
R4
}
}
100125
}
Ambient Temperature (°C)
Figure 1. Derating Curves for RT9986A Packages
}
Place the feedback components as close as possible to
the FB pin and keep away from noisy devices.
C3
V
OUT_CH1
GND
C21
R2
V
BAT
C4
GND
C16
FB1
D1C18
C15
V
OUT_CH6
D4D3D2
R11
R12
VREF
FB6
VOUT6
FB7
PVDD7
L7
R13
GND
L4
C10
R8
GND
C20C19
LX7
EN7
1
2
3
4
V
BAT
C6
C2
GND
GND
LX6
R1
L1
E
N
5
6
P
V
D
D
1
B
A
T
323
E
N
1
2
3
4
L6
P
V
D
D
2
L
X
1
L
X
6
L2
L
X
2
C22
Connect the
Exposed Pad to
a ground plane.
25
24
23
22
21
20
19
18
17
FB2
SYSR
RTCPWR
VDDM
LX5
PVDD5
FB5
RST
R10
L5
V
BAT
GND
C1
C14
V
OUT_CH5
C12
R9
C13
GND
5
6
33
7
8
916
P
V
D
D
4
F
B
4
V
C
H
K
L
X
4
V
N
E
G
F
B
3
P
V
D
D
3
L
X
3
V
OUT_CH4
R7
L3
V
OUT_CH3
C8
GND
R6
R5
C9
V
BAT
C7
Input/Output capacitors must be placed as
close as possible to the Input/Output pins.
LX should be connected to Inductor by wide and short
trace, keep sensitive components away from this trace
Figure 2. PCB Layout Guide
DS9986A-00 May
21
RT9986A
Table 2. Protection Items
Threshold (typical)
Protection
Refer to Electrical Protection methods
type
spec
UVLO BAT < 1.3V IC Shutdown.
Automatic reset at VDDM <
5.75V
IC Shutdown.
IC
Shutdown
Delay time
No-delay
Reset method
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power
reset or all enable
pins set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
BAT
OVP
VDDM
UVLO
Current
Limit
PVDD1
OVP
CH1
PVDD1
Step-Up
UVP
VDDM > 6V 100ms
VDDM < 2.4V
N-MOSFET
Current > 3A
PVDD1 > 6V
No-delay
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock 100ms
cycle.
N-MOSFET off, P-MOSFET off. No-delay
PVDD1 < (BAT − 0.8V)
or PVDD1 < 1.28V after N-MOSFET off, P-MOSFET off. 100ms
soft-start end.
N-MOSFET off, P-MOSFET off. No-delay
IC Shutdown when OL occur
each cycle until 100ms.
FB1 < 0.4V after
FB1 UVP
soft-start end.
FB1 Over
FB1 < 0.7V
Load (OL)
Current
Limit
PVDD2
OVP
CH2
Step-Up
PVDD2
UVP
FB2 UVP
100ms
N-MOSFET off, P-MOSFET off.
N-MOSFET Current >
Automatic reset at next clock 100ms
3A
cycle.
PVDD2 > 6V N-MOSFET off, P-MOSFET off. No-delay
PVDD2 < (BAT − 0.8V)
or PVDD2 < 1.28V after N-MOSFET off, P-MOSFET off. 100ms
soft-start end.
FB2 < 0.4V after
soft-start end.
N-MOSFET off, P-MOSFET off. No-delay
IC Shutdown when OL occur
each cycle until 100ms.
FB2 Over
FB2 < 0.7V
Load
Current
Limit
P-MOSFET
Current > 1.6A
100ms
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock 100ms
cycle.
N-MOSFET off, P-MOSFET off. No-delay
IC Shutdown when OL occur
each cycle until 100ms.
CH2 FB2 < 0.4V after
FB2 UVP
Step-Down soft-start end.
FB2 Over
FB2 < 0.7V
Load
100ms
22
To be continued
DS9986A-00 May 2011
RT9986A
Threshold (typical)
Protection
Refer to Electrical
type
spec
Current
Limit
CH3
FB3 UVP
Step-Down
FB3 Over
Load
Current
Limit
CH4
FB4 UVP
Step-Down
FB4 Over
Load
Current
Limit
PVDD5
OVP
FB5 UVP
FB5 Over
Load
Current
Limit
VOUT6
OVP
FB6 UVP
FB6 Over
Load
Current
Limit
PVDD7
OVP
P-MOSFET
Current > 1.6A
FB3 < 0.4V after
soft-start end.
FB3 < 0.7V
P-MOSFET
Current > 1.6A
FB4 < 0.4V after
soft-start end.
FB4 < 0.7V
N-MOSFET
Current > 1.2A
PVDD5 > 21V
FB5 < 0.6V after
soft-start end.
FB5 < 1.1V
P-MOSFET
Current > 1.5A
VOUT6 < −13V
Protection methods
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
cycle.
N-MOSFET off, P-MOSFET off.
IC Shutdown when OL occur
each cycle until 100ms.
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
cycle.
N-MOSFET off, P-MOSFET off.
IC Shutdown when OL occur
each cycle until 100ms.
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
cycle.
N-MOSFET off, P-MOSFET off.
IC
Shutdown
Delay time
Reset method
CH5
Step-Up
N-MOSFET off, P-MOSFET off.
IC Shutdown when OL occur
each cycle until 100ms.
P-MOSFET off. Automatic reset
at next clock cycle.
P-MOSFET off.
CH6
Inverter
FB6 >1.2V P-MOSFET off.
IC Shutdown when OL occur
each cycle until 100ms.
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
cycle.
Shutdown CH7
FB6 > 0.74V
N-MOSFET
Current > 0.8A
PVDD7 > 15V
CH7
WLED
Thermal
Thermal Temperature >
Shutdown 160°C
All channels stop switching
VDDM power
100ms reset or all enable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
Not
reset or all enable
applicable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
23
DS9986A-00 May 2011
RT9986A
Outline Dimension
1
2
1
2
DETAIL A
Pin #1 ID and Tie Bar Mark Options
Note : The configuration of the Pin #1 identifier is optional,
but must be located within the zone indicated.
Symbol
A
A1
A3
b
D
D2
E
E2
e
L
Dimensions In Millimeters
Min
0.700
0.000
0.175
0.150
3.900
2.650
3.900
2.650
0.400
0.300 0.400
Max
0.800
0.050
0.250
0.250
4.100
2.750
4.100
2.750
Dimensions In Inches
Min
0.028
0.000
0.007
0.006
0.154
0.104
0.154
0.104
0.016
0.012 0.016
Max
0.031
0.002
0.010
0.010
0.161
0.108
0.161
0.108
W-Type 32L QFN 4x4 Package
Richtek Technology Corporation
Headquarter
5F, No. 20, Taiyuen Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Richtek Technology Corporation
Taipei Office (Marketing)
5F, No. 95, Minchiuan Road, Hsintien City
Taipei County, Taiwan, R.O.C.
Tel: (8862)86672399 Fax: (8862)86672377
Email: marketing@
Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit
design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be
guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek.
24
DS9986A-00 May 2011
2024年10月6日发(作者：堵书兰)
RT9986A
7-CH DC/DC Converter for DSC
General Description
The RT9986A is a complete power supply solution for
digital still cameras and other handheld devices. It includes
one synchronous step-up DC/DC converter with load
disconnect, one selectable synchronous step-up/step-
down DC/DC converter, two synchronous step-down DC/
DC converters, one synchronous high voltage step-up DC/
DC converter, one inverting DC/DC converter, and one
selectable synchronous high voltage step-up/current-
source for WLED. In addition, the RT9986A also includes
one RTC_LDO, one voltage detector, and one System
Reset. All power MOSFETs are integrated in the RT9986A.
The RT9986A is designed to fulfill the applications for DSC
as follows :
CH1 is a synchronous step-up output for motor or DSC
system I/O power
CH2 is a selectable synchronous step-up/step-down
output for motor or DSC system I/O power
CH3 and CH4 are synchronous step-down outputs for DSP
core and memory power supply
CH5 is a synchronous high voltage step-up output for CCD
bias power supply
CH6 is an inverting output for negative CCD bias power
supply
CH7 is a selectable synchronous high voltage step-up/
current source for driving WLED
The selectable step-up/step-down converter can be auto
selected by external component topology. For the
RT9986A, all 7-CHs have built in internal compensation.
The RT9986A also provides a transformerless inverting
converter for supplying CCD power. For the low voltage
synchronous step-up and step down converters, efficiency
can be up to 95%.
The RT9986A provides comprehensive protection features
including over current protection, thermal shutdown
protection, over voltage protection, overload protection,
and under voltage protection.
z
Features
z
CH2 Step-Up/Step-Down Auto-Selected by External
Topology
Preset On/Off Sequence of CH1, CH2, CH3, CH4
(1
→
3
→
4
→
2)
Preset On/Off Sequence of CH5, CH6 (5
→
6)
All Channels with Internal Compensation
All Power Switches Integrated
All Step-Up Converter with Load Disconnect
Step-Down DC/DC Converter
`
Up to 95% Efficiency
`
100% (max) Duty Cycle
Low Voltage Step-Up DC/DC Converter
`
Adjustable Output Voltage
`
Up to 95% Efficiency
WLED Driver
`
Auto-Selected by External Topology
`
Current Source Mode with 30mA DC Current
`
Step-Up Mode with LED Open Protection (OVP7)
`
Direct PWM Dimming Control
Fixed 2MHz Switching Frequency for CH1/2/3/4,
Fixed 1MHz Switching Frequency for CH5/6/7
Small 32-Lead WQFN Package
RoHS Compliant and Halogen Free
z
z
z
z
z
z
z
z
z
z
Applications
z
z
z
Digital Still Camera
PDA
Portable Devices
Marking Information
EZ= : Product Code
EZ=YM
DNN
YMDNN : Date Code
DS9986A-00 May
1
RT9986A
Ordering Information
RT9986A
Package Type
QW : WQFN-32L 4x4 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb
Free)
Note :
Richtek products are :
`
RoHS compliant and compatible with the current require-
Pin Configurations
(TOP VIEW)
E
N
5
6
L
X
1
P
V
D
D
1
B
A
T
L
X
6
P
V
D
D
2
L
X
2
E
N
1
2
3
4
32313
FB1
VREF
FB6
VOUT6
FB7
PVDD7
LX7
EN7
1
2
3
4
5
6
7
8
916
24
23
22
GND
33
21
20
19
18
17
FB2
SYSR
RTCPWR
VDDM
LX5
PVDD5
FB5
RST
`
Suitable for use in SnPb or Pb-free soldering processes.
2
L
X
4
P
V
D
D
4
F
B
4
V
C
H
K
V
N
E
G
F
B
3
P
V
D
D
3
L
X
3
ments of IPC/JEDEC J-STD-020.
WQFN-32L 4x4
DS9986A-00 May 2011
RT9986A
Typical Application Circuit
For 2AA
21
C1
1µF
V
BAT
29
C2
4.7µF
L5
10µH
V
BAT
C14
4.7µF
VDDM
PVDD1
FB1
RT9986A
30
1
C21
4.7pF
R1
470k
R2
88.7k
C4
10µF x 2
5V
BAT
20
LX5
LX1
31
L1
2.2µH
C3
4.7µF
V
BAT
15V
C13
10µF x 2
R9
287k
R10
26.1k
C12
27pF
19
PVDD5
PVDD2
27
24
C22
4.7pF
R3
470k
R4
150k
C6
10µF x 2
3.3V
18
FB5
FB2
4
VOUT6
D1
-7V
C18
10µF x 2
C15
1nF
R11
66.5k
R12
10.5k
C16
0.1µF
L6
10µH
28
LX6
LX2
26
L2
2.2µH
C5
4.7µF
C7
4.7µF
V
BAT
PVDD3
15
LX3
16
14
L3
2.2µH
5V
3
2
13
C17
0.1µF
FB6
2.5V
R5
768k
R6
360k
C8
10µF
VREF
VNEG
FB3
7
LX7
6
PVDD7
5
FB7
PVDD4
10
L4
2.2µH
C9
10µF
5V or V
BAT
D5
5V
LX4
9
FB4
11
1.8V
R7
470k
R8
374k
C10
10µF
8
EN7
ON
OFF
RTCPWR
R14
10k
3.3V
R15
100k
25
EN1234
32
EN56
12
VCHK
17
23
RST
RTCPWR
22
C11
Super Cap
33 (Exposed Pad)
GND
SYSR
DS9986A-00 May
3
RT9986A
For Li-ion
21
C1
1µF
V
BAT
29
C2
4.7µF
L5
10µH
V
BAT
C14
4.7µF
VDDM
PVDD1
FB1
RT9986A
LX1
31
L1
2.2µH
C4
4.7µF
V
BAT
30
1
C21
4.7pF
R1
470k
R2
88.7k
5V
C3
10µF x 2
BAT
20
LX5
15V
C13
10µF x 2
R9
287k
R10
26.1k
C12
27pF
19
PVDD5
LX2
26
24
L2
2.2µH
C22
10pF
R3
470k
R4
150k
C5
10µF
3.3V
18
FB5
FB2
4
VOUT6
D1
-7V
C18
10µF x 2
C15
1nF
R11
66.5k
R12
10.5k
C16
0.1µF
L6
10µH
28
LX6
PVDD2
27
C6
4.7µF
C7
4.7µF
V
BAT
PVDD3
15
LX3
16
14
L3
2.2µH
V
BAT
3
2
13
C17
0.1µF
L7
10µH
V
BAT
C19
1µF
D2
D3
D4
R13
10
C20
1µF
5
FB6
1.8V
R5
470k
R6
374k
C8
10µF
VREF
VNEG
FB3
PVDD4
10
7
LX7
LX4
9
6
PVDD7
FB4
11
FB7
RTCPWR
8
EN7
22
C11
Super Cap
33 (Exposed Pad)
L4
2.2µH
C9
4.7µF
5V or V
BAT
1V
R7
23.2k
R8
93.1k
C10
10µF
ON
OFF
RTCPWR
R14
10k
3.3V
R15
100k
25
EN1234
32
EN56
12
17
23
VCHK
RST
SYSR
GND
4
DS9986A-00 May 2011
RT9986A
Timing Diagram
Timing Diagram for CH1 to CH4
VDDM = Max
(BAT, PVDD1)
EN1234
CH1 VOUT
CH3 VOUT
CH4 VOUT
CH2 VOUT
User define
3.5ms
3.5ms
3.5ms
3.5ms
Wait until FB3 < 0.1V
Wait until FB4 < 0.1V
Wait until FB2 < 0.1V
CH5 and CH6 Power Sequence
The power on sequence is :
When EN56 goes high, CH5 will turn on first. After 10ms, CH6 will turn on.
The power off sequence is :
When EN56 goes low, CH6 will turn off first and VOUT6 will be internally pulled to GND.
When VOUT6 > −0.12V, CH6 discharging completes and then CH5 turns off. Finally, the whole IC shuts down.
Power On Sequence : CH5 HV Step-Up 15V
→
CH6 INV −7V
Power Off Sequence : CH6 INV −7V
→
CH5 HV Step-Up 15V
EN56
10ms
Constant Current
Pre-Charge.
10ms
Discharge by internal N-MOSFET
CH5
VOUT
CH6
VOUT
Wait until VOUT6 close to 0V
DS9986A-00 May
5
RT9986A
Functional Pin Description
Pin No.
1
2
3
4
Pin Name
FB1
VREF
FB6
VOUT6
Feedback Input Pin of CH1.
1.8V Reference Output Pin.
Feedback Input Pin of CH6.
Pin Function
Sense Input Pin of CH6 Inverting Output Node.
Feedback input pin of CH7 in step-up mode or current sink pin of CH7 in current
5 FB7
source mode.
6 PVDD7 Power Output Pin of CH7.
Switch Node of CH7 in Step-Up Mode. LX7 initial voltage determines CH7
7 LX7
operation mode.
8 EN7 Enable Pin of CH7 and PWM Dimming Signal Input Pin.
9
10
11
12
13
14
15
16
17
18
19
20
21
LX4
PVDD4
FB4
VCHK
VNEG
FB3
PVDD3
LX3
RST
FB5
PVDD5
LX5
VDDM
Switch Node of CH4.
Power Input Pin of CH4.
Feedback Input Pin of CH4.
Sense Pin of Voltage Detector.
Output Pin of Negative Regulator.
Feedback Input Pin of CH3.
Power Input Pin of CH3.
Switch Node of CH3.
Voltage Detector Open Drain Output Pin.
Feedback Input Pin of CH5.
Power Output Pin of CH5.
Switch Node of CH5.
IC Analog Power Pin.
Internal Control Circuit Power Pin. That must connect to a bypass capacitor for
22 RTCPWR
better noise rejection.
23 SYSR System Reset Open-Drain Output Pin.
24
25
26
FB2
EN1234
LX2
Feedback Input Pin of CH2.
Enable Pin of CH1, CH2, CH3, CH4.
Switch Node of CH2.
Power Input Pin for Step-Down of CH2.
27 PVDD2
Power Output Pin for Step-Up of CH2.
28 LX6 Switch Node of CH6.
29 BAT Battery Power Pin.
30
31
32
PVDD1
LX1
EN56
Power Output Pin of CH1.
Switch Node of CH1.
Enable Pin of CH5, CH6.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum thermal dissipation.
33 (Exposed pad) GND
6
DS9986A-00 May 2011
RT9986A
Function Block Diagram
VDDM
PVDD5
Body
Diode
Control
BAT
VDDM
BAT
LX5
UVLOUVLO
CH5
C-Mode
Step-Up
PWM
Soft-Start
VDDI
VDDM
PVDD1
Body
Diode
Control
FB5
1.25V
REF
-
+
BAT
VDDM
CH1
C-Mode
Step-Up
BAT
LX1
CH6
Inverting
LX6
VNEG
-
+
0.8V
REF
VDDM
FB1
VOUT6
FB6
1.8V
REF
VDDM
CH7 C-Mode
Step-Up or
Current Source
+
PWM Dimming
+
Mode Selector
-
+
PVDD2
Body
Diode
Control
BAT
LX2
+
0.6V
REF
-
CH2
C-Mode
Step-Up or
Step-Down
VREF
PVDD7
BAT
LX7
Body
Diode
Control
-
+
0.8V
REF
VDDM
FB2
PVDD3
FB7
0.25V
REF
30mA(max.)
CH3
C-Mode
Step-Down
LX3
EN7
EN1234
EN56
Power On/Off
Sequence Control
Logic Block
VDDM
RTCPWR
VCHK
RST
Voltage
Detector
CH4
C-Mode
Step-Down
-
+
0.8V
REF
PVDD4
FB3
LX4
VDDM
SYSR
SYS_Reset
GND
FB2
VDDI
-
+
0.8V
REF
FB4
RTC_LDO
W/ Body Diode
Control
RTCPWR
DS9986A-00 May
7
RT9986A
Absolute Maximum Ratings
(Note 1)
z
z
z
z
z
z
z
z
z
z
z
z
z
Supply Input Voltage, VDDM, BAT---------------------------------------------------------------------−0.3V to 6V
VOUT6--------------------------------------------------------------------------------------------------------−10V to 0.3V
LX1, LX2, LX3, LX4-----------------------------------------------------------------------------------------−0.3V to 6V
PVDD5, LX5-------------------------------------------------------------------------------------------------−0.3V to 24V
PVDD7, LX7-------------------------------------------------------------------------------------------------−0.3V to 17V
LX6-------------------------------------------------------------------------------------------------------------(BAT − 14V) to (BAT + 0.3V)
Other Pins----------------------------------------------------------------------------------------------------−0.3V to 6V
Power Dissipation, P
D
@ T
A
= 25°C
WQFN 32L 4x4----------------------------------------------------------------------------------------------3.590W
Package Thermal Resistance (Note 2)
WQFN 32L 4x4, θ
JA
----------------------------------------------------------------------------------------27.8°C/W
WQFN 32L 4x4, θ
JC
----------------------------------------------------------------------------------------7°C/W
Junction Temperature--------------------------------------------------------------------------------------150°C
Lead Temperature (Soldering, 10 sec.)----------------------------------------------------------------260°C
Storage Temperature Range-----------------------------------------------------------------------------−65°C to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Mode)-------------------------------------------------------------------------------2kV
MM (Machine Mode)---------------------------------------------------------------------------------------200V
Recommended Operating Conditions
(Note 4)
z
z
z
VDDM---------------------------------------------------------------------------------------------------------2.7V to 5.8V
Junction Temperature Range-----------------------------------------------------------------------------
−
40°C to 125°C
Ambient Temperature Range-----------------------------------------------------------------------------
−
40°C to 85°C
Electrical Characteristics
Supply Input Voltage
BAT Startup Voltage
BAT UVLO Threshold
BAT UVLO Hysteresis
VDDM OVP Threshold
VDDM OVP Hysteresis
VDDM UVLO Threshold
VDDM UVLO Hysteresis
Supply
Current
(V
DDM
= V
BAT
= 3.3V, T
A
= 25°C, unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
V
ST
BAT Falling
VDDM Rising
VDDM Rising
1.5 -- -- V
-- 1.3 -- V
-- 0.2 -- V
5.85
--
2.2
--
6 6.15 V
−0.25 -- V
2.4
0.3
2.6
--
V
V
Shutdown Supply Current
(I
BAT
+ I
VDDM
)
CH1 Synchronous Step-Up Supply
Current into VDDM
CH2 Synchronous Step-Up or
Step-Down Supply Current into VDDM
I
OFF
All EN pins = 0, V
BAT
= 3.3V --
--
--
--
10
--
--
--
20
800
800
800
μA
μA
μA
μA
I
Q1
Non switching, V
EN1234
= 3.3V
I
Q2
Non switching, V
EN1234
= 3.3V
V
EN1234
= 3.3V
CH3 Synchronous Step-Down Supply
I
Q3
Current into VDDM
8
To be continued
DS9986A-00 May 2011
RT9986A
Parameter Symbol Test Conditions Min Typ Max Unit
CH4 Synchronous Step-Down
Non switching, V
EN1234
= 3.3V -- -- 800 μA
I
Q4
Supply Current into VDDM
CH5 Synchronous Step-Up Supply
Non switching, V
EN56
= 3.3V -- -- 800 μA
I
Q5
Current into VDDM
CH6 (Inverting)
I
Q6
Non switching, V
EN56
= 3.3V -- -- 800 μA
Supply Current into VDDM
CH7 (WLED) in Step-Up Mode
Non switching, V
EN7
= 3.3V -- -- 800 μA
I
Q7b
Supply Current into VDDM
CH7 (WLED) in Current Source
V
EN7
= 3.3V, V
LX7
= 0V -- -- 800 μA
I
Q7c
Mode Supply Current into VDDM
Oscillator
CH1, 2, 3, 4 Operation Frequency
CH5, 6, 7 Operation Frequency
CH2 Maximum Duty Cycle (Step-Up)
CH2 Maximum Duty Cycle
(Step-Down)
CH3 Maximum Duty Cycle
(Step-Down)
CH4 Maximum Duty Cycle
(Step-Down)
CH5 Maximum Duty Cycle (Step-Up)
f
OSC
f
OSC2
CH7 in Step-Up mode
V
FB1
= 0.75V
V
FB2
= 0.75V
V
FB2
= 0.75V
V
FB3
= 0.75V
V
FB4
= 0.75V
V
FB5
= 1.15V
V
FB6
= 0.7V
V
FB7
= 0.15V
1800 2000 2200 kHz
900
80
80
--
--
--
91
91
91
1000
83
83
--
--
--
93
93
93
1100
86
86
100
100
100
97
97
97
kHz
%
%
%
%
%
%
%
%
CH1 Maximum Duty Cycle (Step-Up)
CH6 Maximum Duty Cycle (Inverting)
CH7 Maximum Duty Cycle (Step-Up)
Feedback, Regulation Voltage
Feedback Regulation Voltage @
FB1, FB2, FB3, FB4
Feedback Regulation Voltage @ FB5
Feedback Regulation Voltage @ FB6
(Inverting)
Feedback Regulation Voltage @ FB7
Output Current (CS Mode)
Dropout Voltage @ FB7 (CS Mode)
VREF Output Voltage
VREF Load Regulation
PowerSwitch
V
FB5
V
FB6
V
FB7
V
LX7
= 0V
0.788 0.8 0.812 V
1.237 1.25 1.263 V
0.59 0.6 0.61 V
0.237 0.25 0.263 V
28.5
--
30
--
31.5
0.3
mA
V
V
REF
1.782 1.8 1.818 V
0μA < I
REF
< 200μA -- -- 10 mV
-- 200 300 P-MOSFET V
PVDD1
= 3.3V
R
DS(ON)1
N-MOSFET V
PVDD1
= 3.3V
CH1 Current Limitation (Step-Up) I
LIM1
P-MOSFET V
PVDD2
= 3.3V
CH2 On Resistance R
DS(ON)2
N-MOSFET V
PVDD2
= 3.3V
CH1 On-Resistance
CH2 Current Limitation (Step-Down) I
LIM2_D
CH2 Current Limitation (Step-Up)
DS9986A-00 May 2011
mΩ
-- 150 250
2.2 3 4 A
-- 200 300
mΩ
-- 150 250
1.2 1.6 2 A
2.2 3 4 A
To be continued
9
I
LIM2_U
RT9986A
CH3 On Resistance
P-MOSFET V
PVDD3
= 3.3V
R
DS(ON)3
N-MOSFET V
PVDD3
= 3.3V
P-MOSFET V
PVDD4
= 3.3V
R
DS(ON)4
N-MOSFET V
PVDD4
= 3.3V
--
--
--
--
300
300
300
300
400
400
400
400
mΩ
Parameter Symbol Test Conditions Min Typ Max Unit
CH3 Current Limitation (Step-Down) I
LIM3
CH4 On Resistance
1.2 1.6 2 A
mΩ
CH4 Current Limitation (Step-Down) I
LIM4
P-MOSFET V
PVDD5
= 16V
R
DS(ON)5
N-MOSFET V
PVDD5
= 3.3V
CH5 Current Limitation of
I
LIM5
N-MOSFET
CH6 On Resistance of P-MOSFET R
DS(ON)6
CH6 Current Limitation of
I
LIM6
P-MOSFET
P-MOSFET V
PVDD7
= 10V
CH7 On Resistance R
DS(ON)7
N-MOSFET V
PVDD7
= 3.3V
CH7 Current Limitation of
I
LIM7
N-MOSFET
Protection
Over Voltage Protection of PVDD1
and PVDD2
Over Voltage Protection of PVDD5
CH5 On Resistance
1.2 1.6 2 A
-- 0.8 1
-- 0.6 0.8
Ω
0.9 1.2 1.6 A
-- 0.5 0.7 Ω
1 1.5 2 A
-- 3 --
Ω
-- 0.9 1.1
0.6 0.8 1 A
5.85 6 6.15 V
20
--
21 22 V
Over Voltage Protection of VOUT6
Over Voltage Protection of PVDD7
(Step-Up Mode)
CH1, CH2 Step-Up Under Voltage
Protection of PVDD1 and PVDD2
CH1/2/3/4 Under Voltage Protection
CH5 Under Voltage Protection
CH6 Under Voltage Protection
CH1/2/3/4 Over Load Protection
CH5 Over Load Protection
CH6 Over Load Protection
Protection Fault Delay
Control
−13 -- V
At V
FBx
< 0.4V after soft-start
ends
At V
FB5
< 0.6V after soft-start
ends
At V
FB6
> 1.2V after soft-start
end
At V
FBx
< 0.7V after fault delay
(100ms)
At V
FB5
< 1.1V after fault delay
(100ms)
At V
FB6
> 0.74V after fault
delay (100ms)
High to Select Step-Up Mode
Low to Select CS Mode
14.3 15 16 V
V
BAT
-- V --
−0.8V
0.35 0.4 0.45 V
0.5 0.6 0.7 V
1.1 1.2 1.3 V
0.65 0.7 0.75 V
1.05 1.1 1.15 V
0.69 0.74 0.79 V
--
1.3
--
1
--
--
100
--
--
--
0.25
2
--
--
0.4
--
--
6
ms
Logic-High
EN1234, EN56, EN7
Input Threshold Voltage
Logic-Low
LX7 Input Threshold
Voltage
Logic-High
Logic-Low
V
V
μA EN1234, EN56, EN7 Sink Current
EN7 Low Time for Shutdown
10
t
SHDN
-- 32 -- ms
To be continued
DS9986A-00 May 2011
RT9986A
Thermal Protection
Thermal Shutdown
Thermal Shutdown Hysteresis
System Reset
SYSR, FB2 Regulation Threshold
SYSR, FB2 Hysteresis
SYSR Rising Delay Time
SYSR Sink Capability
Voltage Detector
Voltage Detector Reset Threshold
(VCHK
<
Threshold Æ RST = L)
Voltage Detector Reset Hysteresis
Standby Current
RST Rising Delay Time
RST Sink Capability
RTC LDO
for SYSR to go low
V
SYSR
= 0.5V
0.709 0.72 0.731
--
--
4
40
10
--
--
--
--
V
mV
ms
mA
T
SD
ΔT
SD
125 160 -- °C
-- 20 -- °C
Parameter Symbol Test Conditions Min Typ Max Unit
VCHK Falling
V
VCHK
= 3V
V
RST
= 0.5V, V
VCHK
= 1.5V
V
DDM
= 4.2V
I
OUT
= 0mA
V
DDM
= 4.2V
I
OUT
= 50mA
I
OUT
= 10mA
I
OUT
= 3mA
1.57 1.6 1.63 V
--
--
4
--
3.1
60
--
--
--
16
2
--
5
3.2
130
--
--
--
--
4
--
8
3.3
200
1000
150
60
mV
mV
μA
mA
μA
V
mA
35 55 75 ms
Standby Current
Regulated Output Voltage @
RTCPWR
Max Output Current (Current Limit)
Dropout Voltage
Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for
stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational
sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may
remain possibility to affect device reliability.
Note 2. θ
JA
is measured in natural convection at T
A
= 25°C on a high-effective thermal conductivity four-layer test board of JEDEC
51-7 thermal measurement standard. The measurement case position of θ
JC
is on the exposed pad of the package.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
DS9986A-00 May
11
RT9986A
Typical Operating Characteristics
CH1 Step-Up Efficiency vs. Output Current
100
90
80
CH1 Step-Up Efficiency vs. Output Current
100
90
E
f
f
i
c
i
e
n
c
y
(
%
)
60
50
40
30
20
10
0
10
E
f
f
i
c
i
e
n
c
y
(
%
)
70
V
BAT
= 4.5V
V
BAT
= 4.2V
V
BAT
= 3.9V
V
BAT
= 3.6V
V
BAT
= 3.3V
V
BAT
= 3V
80
70
60
50
40
30
20
V
BAT
= 3V
V
BAT
= 2.7V
V
BAT
= 2.5V
V
BAT
= 2.2V
V
BAT
= 2V
V
BAT
= 1.8V
V
OUT
= 5V, L = 2.2μH, C
OUT
= 10μF x 2
1001000
10
0
10
V
OUT
= 3.3V, L = 2.2μH, C
OUT
= 10μF x 2
1001000
Output Current (mA)Output Current (mA)
CH2 Step-Up Efficiency vs. Output Current
100
90
80
CH2 Step-Down Efficiency vs. Output Current
100
90
E
f
f
i
c
i
e
n
c
y
(
%
)
60
50
40
30
20
10
0
10
E
f
f
i
c
i
e
n
c
y
(
%
)
70
V
BAT
= 3.6V
V
BAT
= 3.3V
V
BAT
= 3V
V
BAT
= 2.7V
V
BAT
= 2.5V
V
BAT
= 2.2V
V
BAT
= 1.8V
80
70
60
50
40
30
20
V
BAT
= 3.4V
V
BAT
= 3.7V
V
BAT
= 3.9V
V
BAT
= 4.2V
V
BAT
= 4.5V
V
BAT
= 5V
V
OUT
= 5V, L = 2.2μH, C
OUT
= 10μF x 2
1001000
10
0
10
V
OUT
= 3.3V, L = 2.2μH, C
OUT
= 10μF
1001000
Output Current (mA)Output Current (mA)
CH 3 Step-Down Efficiency vs. Output Current
100
90
80
CH4 Step-Down Efficiency vs. Output Current
100
90
E
f
f
i
c
i
e
n
c
y
(
%
)
E
f
f
i
c
i
e
n
c
y
(
%
)
70
60
50
40
30
20
10
0
10
V
BAT
= 2.7V
V
BAT
= 3V
V
BAT
= 3.3V
V
BAT
= 3.6V
V
BAT
= 3.9V
V
BAT
= 4.2V
V
BAT
= 4.5V
80
70
60
50
40
30
20
V
BAT
= 1.8V
V
BAT
= 2.5V
V
BAT
= 3V
V
BAT
= 3.3V
V
BAT
= 3.6V
V
BAT
= 4.2V
V
BAT
= 4.5V
V
OUT
= 1.8V, L = 2.2μH, C
OUT
= 10μF
1001000
10
0
10
V
OUT
= 1V, L = 2.2μH, C
OUT
= 10μF
1001000
Output Current (mA)Output Current (mA)
12
DS9986A-00 May 2011
RT9986A
CH5 Step-Up Efficiency vs. Output Current
100
90
CH6 Inverting Efficiency vs. Output Current
100
90
E
f
f
i
c
i
e
n
c
y
(
%
)
70
60
50
40
30
20
10
0
0.001
V
BAT
= 4.5V
V
BAT
= 4.2V
V
BAT
= 3.9V
V
BAT
= 3.6V
V
BAT
= 3.3V
V
BAT
= 3V
V
BAT
= 2.7V
V
BAT
= 2.5V
V
BAT
= 2.2V
V
BAT
= 2V
V
OUT
= 16V, L = 10μH, C
OUT
= 10μF x 2
0.010.1
I
n
v
e
r
t
i
n
g
E
f
f
i
c
i
e
n
c
y
(
%
)
8080
70
60
50
40
30
20
10
0
1
V
BAT
= 4.2V
V
BAT
= 3.9V
V
BAT
= 3.6V
V
BAT
= 3.3V
V
BAT
= 3V
V
BAT
= 2.7V
V
BAT
= 4.5V
V
BAT
= 2.5V
V
BAT
= 2.2V
V
BAT
= 2V
V
OUT
= −8V, L = 10μH, C
OUT
= 10μF x 2
10100
Output Current (A)Output Current (mA)
CH7 Efficiency vs. Input Voltage
100
90
80
CH1 Step-Up Output Voltage vs. Output Current
5.20
5.15
E
f
f
i
c
i
e
n
c
y
(
%
)
70
60
50
40
30
20
10
0
1.82.12.42.733.33.63.94.24.5
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
5.10
5.05
5.00
4.95
4.90
4.85
V
BAT
= 3V
V
BAT
= 4.5V
I
OUT
= 25mA, L = 10μH, C
OUT
= 1μF
4.80
0
V
OUT
= 5V
500600
Input Voltage (V)Output Current (mA)
CH1 Step-Up Output Voltage vs. Output Current
3.35
CH2 Step-Up Output Voltage vs. Output Current
5.10
3.33
V
BAT
= 1.8V
5.08
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
V
BAT
= 3V
5.06
3.31
V
BAT
= 3.2V
V
BAT
= 4.2V
5.04
3.29
3.27
5.02
V
OUT
= 3.3V
3.25
0500600
5.00
0
V
OUT
= 5V
500600
Output Current (mA)Output Current (mA)
DS9986A-00 May
13
RT9986A
CH2 Step-Down Output Voltage vs. Output Current
3.36
CH3 Step-Down Output Voltage vs. Output Current
1.830
1.825
3.34
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
3.32
V
BAT
= 4.5V
V
BAT
= 5V
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
1.820
1.815
1.810
1.805
3.30
V
BAT
= 3V
V
BAT
= 4.5V
3.28
V
OUT
= 3.3V
3.26
0500600
1.800
0
V
OUT
= 1.8V
500600
Output Current (mA)Output Current (mA)
CH4 Step-Down Output Voltage vs. Output Current
1.006
1.004
CH5 Step-Up Output Voltage vs. Output Current
16.3
16.2
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
1.002
1.000
0.998
0.996
0.994
0.992
V
BAT
= 4.5V
V
BAT
= 2.7V
V
BA
T
= 3V
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
16.1
V
BAT
= 3.4V
V
BAT
= 4.5V
16.0
15.9
V
OUT
= 1V
15.8
400500600
0204060
V
OUT
= 16V
80100
Output Current (mA)
Output Current (mA)
CH6 Inverting Efficiency vs. Output Current
-8.190
Power On Sequence
O
u
t
p
u
t
V
o
l
t
a
g
e
(
V
)
-8.195
V
BAT
= 2.7V
V
BAT
= 3.4V
V
BAT
= 4.5V
V
OUT_CH1
(5V/Div)
V
OUT_CH2
(2V/Div)
V
OUT_CH3
(2V/Div)
V
OUT_CH4
(2V/Div)
Time (2.5ms/Div)
-8.200
-8.205
V
OUT
= −8V
-8.210
V
BAT
=
3.7V
Output Current (mA)
14
DS9986A-00 May 2011
RT9986A
Power Off Sequence
V
OUT_CH1
(5V/Div)
V
OUT_CH2
(2V/Div)
V
OUT_CH3
(2V/Div)
V
OUT_CH4
(2V/Div)
Time (1ms/Div)
Power On Sequence
V
OUT_CH5
(10V/Div)
V
OUT_CH6
(5V/Div)
V
BAT
=
3.7VV
BAT
=
3.7V
Time (5ms/Div)
Power Off SequenceCH1 Output Voltage Ripple
V
OUT_CH5
(10V/Div)
V
OUT_CH6
(5V/Div)
LX1
(2V/Div)
V
OUT_CH1_ac
(10mV/Div)
V
BAT
=
3.7V
V
BAT
= 3.7V, V
OUT
= 5V,
I
OUT
= 400mA, L = 2.2μH, C
OUT
= 10μF x 2
Time (2.5ms/Div)Time (500ns/Div)
CH2 Output Voltage RippleCH3 Output Voltage Ripple
LX2
(2V/Div)
LX3
(2V/Div)
V
OUT_CH2_ac
(2mV/Div)
V
BAT
= 3.7V, V
OUT
= 3.3V,
I
OUT
= 400mA, L = 2.2μH, C
OUT
= 10μF
V
OUT_CH3_ac
(5mV/Div)
V
BAT
= 3.7V, V
OUT
= 1.8V,
I
OUT
= 400mA, L = 2.2μH, C
OUT
= 10μF
Time (500ns/Div)Time (500ns/Div)
DS9986A-00 May
15
RT9986A
CH4 Output Voltage Ripple
CH5 Output Voltage Ripple
LX4
(2V/Div)
LX5
(10V/Div)
V
OUT_CH4_ac
(5mV/Div)
V
BAT
= 3.7V, V
OUT
= 1V,
I
OUT
= 400mA, L = 2.2μH, C
OUT
= 10μF
V
OUT_CH5_ac
(10mV/Div)
V
BAT
= 3.7V, V
OUT
= 16V,
I
OUT
= 30mA, L = 10μH, C
OUT
= 10μF
Time (500ns/Div)Time (1μs/Div)
CH6 Output Voltage RippleCH1 Load Transient Response
LX6
(10V/Div)
I
OUT
(100mA/Div)
V
OUT_CH1_ac
(100mV/Div)
V
BAT
= 3.7V, V
OUT
= −8V,
I
OUT
= 50mA, L = 10μH, C
OUT
= 10μF x 2
V
BAT
= 3.7V, V
OUT
= 5V,
I
OUT
= 0 to 300mA, L = 2.2μH, C
OUT
= 10μF x 2
V
OUT_CH6_ac
(10mV/Div)
Time (1μs/Div)Time (1ms/Div)
CH2 Load Transient ResponseCH3 Load Transient Response
I
OUT
(100mA/Div)
V
OUT_CH2_ac
(50mV/Div)
V
BAT
= 3.7V, V
OUT
= 3.3V,
I
OUT
= 0 to 300mA, L = 2.2μH, C
OUT
= 10μF
I
OUT
(100mA/Div)
V
OUT_CH3_ac
(50mV/Div)
V
BAT
= 3.7V, V
OUT
= 1.8V,
I
OUT
= 0 to 300mA, L = 2.2μH, C
OUT
= 10μF
Time (1ms/Div)Time (1ms/Div)
16
DS9986A-00 May 2011
RT9986A
CH4 Load Transient Response
CH5 Load Transient Response
I
OUT
(100mA/Div)
V
OUT_CH4_ac
(20mV/Div)
V
BAT
= 3.7V, V
OUT
= 1V,
I
OUT
= 0 to 300mA, L = 2.2μH, C
OUT
= 10μF
I
OUT
(20mA/Div)
V
OUT_CH5_ac
(50mV/Div)
V
BAT
= 3.7V, V
OUT
= 16V,
I
OUT
= 10 to 30mA, C
OUT
= 10μF
Time (1ms/Div)Time (1ms/Div)
CH6 Load Transient Response
I
OUT
(20mA/Div)
V
OUT_CH6_ac
(20mV/Div)
V
BAT
= 3.7V, V
OUT
= −8V,
I
OUT
= 15 to 50mA, C
OUT
= 10μF x 2
Time (1ms/Div)
DS9986A-00 May
17
RT9986A
Application Information
The RT9986A is a multiple output power supply system
for digital still cameras and other small handheld devices.
It includes six DC/DC converters as well as one WLED
driver, one RTC LDO, one voltage detector, and one
system reset. The WLED works in either current source
mode or step-up mode.
CH1 : Step-up synchronous current mode DC/DC converter
with internal power MOSFETs and compensation network.
The P-MOSFET body can be controlled to disconnect the
load.
CH2 : Step-up or step-down synchronous current mode
DC/DC converter with internal power MOSFETs and
compensation network. External circuit topology
automatically determines whether CH2 is in step-up or
step-down mode. During step-up mode, the P-MOSFET
body can be controlled to disconnect the load if input
voltage is not higher than the V
BAT
.
CH3 : Step-down synchronous current mode DC/DC
converter with internal power MOSFETs and
compensation network.
CH4 : Step-down synchronous current mode DC/DC
converter with internal power MOSFETs and
compensation network.
CH5 : Step-up synchronous current mode DC/DC converter
with internal power MOSFET and compensation network.
The P-MOSFET body can be controlled to disconnect the
load.
CH6 : Asynchronous inverting current mode DC/DC
converter with internal power MOSFET and compensation
network.
CH7 : A WLED driver operating in either current source
mode or synchronous step-up mode with internal power
MOSFET and compensation network. Operation mode is
determined by LX7 initial voltage The P-MOSFET body in
step-up mode can be controlled to disconnect the load
disconnected.
CH1 to CH4 operate in PWM mode with 2MHz, while
CH5 to CH7 operate in PWM mode with 1MHz switching
frequency.
RTC_LDO : A 3.1V output LDO with low quiescent current
and high output voltage accuracy.
18
DS9986A-00 May 2011
System Reset : Accurate voltage detector for checking
CH2 output voltage status.
Voltage Detector : A general, low quiescent current voltage
detector for monitoring status of a node voltage such as
for RTC_LDO output or others.
CH1 : Synchronous Step-Up DC/DC Converter
CH1 is a synchronous step-up converter which can be
used for motor power. The converter operates at fixed
frequency and PWM current mode. The converter
integrates internal MOSFETs, compensation network and
synchronous rectifier for up to 95% efficiency.
The output voltage can be set by the following equation :
V
OUT_CH1
= (1 + R1 / R2) x V
FB1
where V
FB1
is 0.8V typically.
CH2 : Synchronous Step-Up / Step-Down
Selectable DC/DC Converter
CH2 is a synchronous step-up / step-down auto-select
converter, typically for system I/O power. In either step-
up or step-down, the converter operates in fixed frequency
PWM mode, Continuous Current Mode (CCM), and
Discontinuous Current Mode (DCM) with internal
MOSFETs, compensation network and synchronous
rectifiers for up to 95% efficiency.
Step-Up :
In step-up mode, CH2 also disconnects the load from its
input power node and discharges output node of CH2 when
it is turned off.
Step-Down :
In step-down mode, the CH2 converter can be operated
at 100% maximum duty cycle to extend the input
operating voltage range. When the input voltage is close
to the output voltage, the converter enters low dropout
mode.
The output voltage can be set by the following equation :
V
OUT_CH2
= (1 + R3 / R4) x V
FB2
where V
FB2
is 0.8V typically.
RT9986A
CH3 : Synchronous Step-Down DC/DC Converter
CH3 operates in fixed frequency PWM mode with
integrated internal MOSFETs and compensation network.
The CH3 step-down converter can be operated at 100%
maximum duty cycle to extend battery operating voltage
range. When the input voltage is close to the output
voltage, the converter enters low dropout mode with low
output ripple.
The output voltage can be set by the following equation :
V
OUT_CH3
= (1 + R5 / R6) x V
FB3
where V
FB3
is 0.8V typically.
CH4 : Synchronous Step-Down DC/DC Converter
CH4 operates at fixed frequency PWM mode with
integrated internal MOSFETs and compensation network.
The CH4 step-down converter can be operated at 100%
maximum duty cycle to extend battery operating voltage
range. When the input voltage is close to the output
voltage, the converter enters low dropout mode with low
output ripple.
The output voltage can be set by the following equation:
V
OUT_CH4
= (1 + R7 / R8) x V
FB4
where V
FB4
is 0.8V typically.
CH5 : Synchronous Step-Up DC/DC Converter
CH5 is a high voltage synchronous step-up converter for
CCD positive power. The converter operates at fixed
frequency PWM mode, CCM, DCM, and PSM (pulse skip
mode) with integrated internal MOSFETs, compensation
network and load disconnect function.
The output voltage can be set by the following equation:
V
OUT_CH5
= (1 + R9 / R10) x V
FB5
where V
FB5
is 1.25V typically.
CH6 : INV DC/DC Converter
This converter integrates an internal P-MOSFET with
internal compensation and needs an external Schottky
diode to provide CCD negative power supply.
The output voltage can be set by the following equation :
V
OUT_CH6
= −(R11 / R12) x (1.2V) + 0.6V
where R11 and R12 are the feedback resistors connected
DS9986A-00 May 2011
to FB6, 1.2V equals to (V
REF
− V
FB6
) and 0.6V is V
FB6
typical.
Reference Voltage
The RT9986A provides a precise 1.8V reference voltage,
V
REF
, with souring capability of 100µA. Connect a 0.1µF
ceramic capacitor from the VREF pin to GND. Reference
voltage is enabled by pulling EN6 to logic-high.
Furthermore, this reference voltage is internally pulled to
GND at shutdown.
CH7 : WLED Driver
CH7 is a WLED driver that can operate in either current
source mode or synchronous step-up mode, as determined
by LX7
'
s initial voltage level.
Table 1. CH7 WLED setting
CH7 Operating Mode
Current Source
Synchronous Step-Up
LX7
< 0.25V
> 1V
When CH7 works in current source mode, it sinks an
accurate LED current modulated by EN7 high duty such
that it is easily dimmed from 0mA to 30mA. If CH7 works
in synchronous step-up mode, it integrates synchronous
step-up mode with an internal MOSFET and internal
compensation to output a voltage up to 15V. The LED
current is set via an external resistor and controlled via
the PWM duty on the EN7 pin. Regardless of the mode,
holding EN7 low for more than 32ms will turn off CH7.
In addition, CH7 will be turned on until the CH2 soft-start
is finished.
CH7 WLED Current Dimming Control
If CH7 is in synchronous step-up mode, the WLED current
is set by an external resistor. If CH7 is in current source
mode, the sink current into the FB7 pin is 30mA typically
when EN7 is high. Regardless of the mode, dimming is
always controlled by the duty of pulse-width modulated
signal on the EN7 pin. The PWM dimming duty must be
over 10%.
The average current through WLED can be set by the
following equations :
I
LED
(mA) = [250mV / R (W)] x Duty (%) (for step-up mode)
or I
LED
(mA) = 30mA x Duty (%) (for current source mode)
19
RT9986A
R is the current sense resistor from FB7 to GND and Duty
is the duty of the PWM dimming signal into EN7 pin.
Dimming frequency range is from 1kHz to 100kHz but
2kHz to 20kHz should be avoided to prevent distraction
from audio noise.
VDDM Bootstrap
To support bootstrap function, the RT9986A includes a
power selection circuit which selects between BAT and
PVDD1 to create the internal node voltage VDDI and VDDM.
VDDM is the power of all the RT9986A control circuits
and must be connected to an external decoupling capacitor
by way of the VDDM pin. The VDDI is the power input of
the RTC LDO. The output PVDD1 of CH1 can bootstrap
VDDM and VDDI. The RT9986A includes UVLO circuits
to monitor VDDM and BAT voltage status.
RTC LDO
The RT9986A provides a 3.1V output LDO for real time
clock. The LDO features low quiescent current (5µA) and
high output voltage accuracy. This LDO is always on, even
when the system is shut down. For better stability, is it
recommended to connect a 0.1µF to the RTCPWR pin.
The RTC LDO includes pass transistor body diode control
to avoid the RTCPWR node from back-charging into the
input node VDDI.
System Reset
The RT9986A also provides a system voltage detector to
monitor system power status via FB2. If FB2 level is lower
than 90% setting, the open drain output pin SYSR will
pull down. When FB2 level is higher than 95% setting,
the SYSR pin will go high after 10ms.
Voltage Detector
The RT9986A provides a voltage detector to detect the
voltage status at the VCHK pin. The input power of the
voltage detector is RTCPWR and the detector is always
on. 55ms after VCHK voltage > 1.616V, the open drain
output /RST will be pulled high. If VCHK < 1.6V, the /RST
pin will be pulled down to GND immediately.
Power On/Off Sequence for CH1 to CH4
EN1234 will turn on/off CH1 to CH4 in preset sequence.
CH1 to CH4 Power On Sequence is:
20
When EN1234 goes high, CH1 will turn on first. 3.5ms
after CH1 is turned on, CH3 will turn on. 3.5ms after CH3
is turned on, CH4 will turn on. 3.5ms after CH4 is turned
on, CH2 will turn on.
CH1 to CH4 Power-Off Sequence is :
When EN1234 goes low, CH2 will turn off first and internally
discharge output.
When FB2 < 0.1V, CH4 will turn off and also internally
discharge output via the LX4 pin. When FB4 < 0.1V, CH3
will turn off and internally discharge output via the LX3
pin. Likewise, when FB3 < 0.1V, CH1 will turn off and
discharge output. After FB1 < 0.1V, CH1 to 4 shutdown
sequence will be completed.
Thermal Considerations
For continuous operation, do not exceed absolute
maximum junction temperature. The maximum power
dissipation depends on the thermal resistance of the IC
package, PCB layout, rate of surrounding airflow, and
difference between junction and ambient temperature. The
maximum power dissipation can be calculated by the
following formula :
P
D(MAX)
= (T
J(MAX)
− T
A
) / θ
JA
where T
J(MAX)
is the maximum junction temperature, T
A
is
the ambient temperature, and θ
JA
is the junction to ambient
thermal resistance.
For recommended operating condition specifications of
the RT9986A, the maximum junction temperature is 125°C
and T
A
is the ambient temperature. The junction to ambient
thermal resistance, θ
JA
, is layout dependent. For WQFN-
32L 4x4 packages, the thermal resistance, θ
JA
, is 27.8°C/
W on a standard JEDEC 51-7 four-layer thermal test board.
The maximum power dissipation at T
A
= 25°C can be
calculated by the following formula :
P
D(MAX)
= (125°C − 25°C) / (27.8°C/W) = 3.59W for
WQFN-32L 4x4 package
The maximum power dissipation depends on the operating
ambient temperature for fixed T
J(MAX)
and thermal
resistance,θ
JA
. For the RT9986A package, the derating
curve in Figure 1 allows the designer to see the effect of
rising ambient temperature on the maximum power
dissipation.
DS9986A-00 May 2011
RT9986A
4.0
M
a
x
i
m
u
m
P
o
w
e
r
D
i
s
s
i
p
a
t
i
o
n
(
W
)
3.6
3.2
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0.0
0255075
Four-Layers PCB
Layout Consideration
For the best performance of the RT9986A, the following
PCB layout guidelines must be strictly followed.
}
Place the input and output capacitors as close as
possible to the input and output pins respectively for
good filtering.
Keep the main power traces as wide and short as
possible.
The switching node area connected to LX and inductor
should be minimized for lower EMI.
Place the feedback components as close as possible
to the FB pin and keep these components away from
the noisy devices.
Connect the GND and Exposed Pad to a strong ground
plane for maximum thermal dissipation and noise
protection.
V
OUT_CH2
C5
GND
R3
R4
}
}
100125
}
Ambient Temperature (°C)
Figure 1. Derating Curves for RT9986A Packages
}
Place the feedback components as close as possible to
the FB pin and keep away from noisy devices.
C3
V
OUT_CH1
GND
C21
R2
V
BAT
C4
GND
C16
FB1
D1C18
C15
V
OUT_CH6
D4D3D2
R11
R12
VREF
FB6
VOUT6
FB7
PVDD7
L7
R13
GND
L4
C10
R8
GND
C20C19
LX7
EN7
1
2
3
4
V
BAT
C6
C2
GND
GND
LX6
R1
L1
E
N
5
6
P
V
D
D
1
B
A
T
323
E
N
1
2
3
4
L6
P
V
D
D
2
L
X
1
L
X
6
L2
L
X
2
C22
Connect the
Exposed Pad to
a ground plane.
25
24
23
22
21
20
19
18
17
FB2
SYSR
RTCPWR
VDDM
LX5
PVDD5
FB5
RST
R10
L5
V
BAT
GND
C1
C14
V
OUT_CH5
C12
R9
C13
GND
5
6
33
7
8
916
P
V
D
D
4
F
B
4
V
C
H
K
L
X
4
V
N
E
G
F
B
3
P
V
D
D
3
L
X
3
V
OUT_CH4
R7
L3
V
OUT_CH3
C8
GND
R6
R5
C9
V
BAT
C7
Input/Output capacitors must be placed as
close as possible to the Input/Output pins.
LX should be connected to Inductor by wide and short
trace, keep sensitive components away from this trace
Figure 2. PCB Layout Guide
DS9986A-00 May
21
RT9986A
Table 2. Protection Items
Threshold (typical)
Protection
Refer to Electrical Protection methods
type
spec
UVLO BAT < 1.3V IC Shutdown.
Automatic reset at VDDM <
5.75V
IC Shutdown.
IC
Shutdown
Delay time
No-delay
Reset method
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power
reset or all enable
pins set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
VDDM power reset
or all enable pins
set to low
BAT
OVP
VDDM
UVLO
Current
Limit
PVDD1
OVP
CH1
PVDD1
Step-Up
UVP
VDDM > 6V 100ms
VDDM < 2.4V
N-MOSFET
Current > 3A
PVDD1 > 6V
No-delay
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock 100ms
cycle.
N-MOSFET off, P-MOSFET off. No-delay
PVDD1 < (BAT − 0.8V)
or PVDD1 < 1.28V after N-MOSFET off, P-MOSFET off. 100ms
soft-start end.
N-MOSFET off, P-MOSFET off. No-delay
IC Shutdown when OL occur
each cycle until 100ms.
FB1 < 0.4V after
FB1 UVP
soft-start end.
FB1 Over
FB1 < 0.7V
Load (OL)
Current
Limit
PVDD2
OVP
CH2
Step-Up
PVDD2
UVP
FB2 UVP
100ms
N-MOSFET off, P-MOSFET off.
N-MOSFET Current >
Automatic reset at next clock 100ms
3A
cycle.
PVDD2 > 6V N-MOSFET off, P-MOSFET off. No-delay
PVDD2 < (BAT − 0.8V)
or PVDD2 < 1.28V after N-MOSFET off, P-MOSFET off. 100ms
soft-start end.
FB2 < 0.4V after
soft-start end.
N-MOSFET off, P-MOSFET off. No-delay
IC Shutdown when OL occur
each cycle until 100ms.
FB2 Over
FB2 < 0.7V
Load
Current
Limit
P-MOSFET
Current > 1.6A
100ms
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock 100ms
cycle.
N-MOSFET off, P-MOSFET off. No-delay
IC Shutdown when OL occur
each cycle until 100ms.
CH2 FB2 < 0.4V after
FB2 UVP
Step-Down soft-start end.
FB2 Over
FB2 < 0.7V
Load
100ms
22
To be continued
DS9986A-00 May 2011
RT9986A
Threshold (typical)
Protection
Refer to Electrical
type
spec
Current
Limit
CH3
FB3 UVP
Step-Down
FB3 Over
Load
Current
Limit
CH4
FB4 UVP
Step-Down
FB4 Over
Load
Current
Limit
PVDD5
OVP
FB5 UVP
FB5 Over
Load
Current
Limit
VOUT6
OVP
FB6 UVP
FB6 Over
Load
Current
Limit
PVDD7
OVP
P-MOSFET
Current > 1.6A
FB3 < 0.4V after
soft-start end.
FB3 < 0.7V
P-MOSFET
Current > 1.6A
FB4 < 0.4V after
soft-start end.
FB4 < 0.7V
N-MOSFET
Current > 1.2A
PVDD5 > 21V
FB5 < 0.6V after
soft-start end.
FB5 < 1.1V
P-MOSFET
Current > 1.5A
VOUT6 < −13V
Protection methods
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
cycle.
N-MOSFET off, P-MOSFET off.
IC Shutdown when OL occur
each cycle until 100ms.
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
cycle.
N-MOSFET off, P-MOSFET off.
IC Shutdown when OL occur
each cycle until 100ms.
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
cycle.
N-MOSFET off, P-MOSFET off.
IC
Shutdown
Delay time
Reset method
CH5
Step-Up
N-MOSFET off, P-MOSFET off.
IC Shutdown when OL occur
each cycle until 100ms.
P-MOSFET off. Automatic reset
at next clock cycle.
P-MOSFET off.
CH6
Inverter
FB6 >1.2V P-MOSFET off.
IC Shutdown when OL occur
each cycle until 100ms.
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
cycle.
Shutdown CH7
FB6 > 0.74V
N-MOSFET
Current > 0.8A
PVDD7 > 15V
CH7
WLED
Thermal
Thermal Temperature >
Shutdown 160°C
All channels stop switching
VDDM power
100ms reset or all enable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
100ms reset or all enable
pins set to low
VDDM power
Not
reset or all enable
applicable
pins set to low
VDDM power
No-delay reset or all enable
pins set to low
23
DS9986A-00 May 2011
RT9986A
Outline Dimension
1
2
1
2
DETAIL A
Pin #1 ID and Tie Bar Mark Options
Note : The configuration of the Pin #1 identifier is optional,
but must be located within the zone indicated.
Symbol
A
A1
A3
b
D
D2
E
E2
e
L
Dimensions In Millimeters
Min
0.700
0.000
0.175
0.150
3.900
2.650
3.900
2.650
0.400
0.300 0.400
Max
0.800
0.050
0.250
0.250
4.100
2.750
4.100
2.750
Dimensions In Inches
Min
0.028
0.000
0.007
0.006
0.154
0.104
0.154
0.104
0.016
0.012 0.016
Max
0.031
0.002
0.010
0.010
0.161
0.108
0.161
0.108
W-Type 32L QFN 4x4 Package
Richtek Technology Corporation
Headquarter
5F, No. 20, Taiyuen Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Richtek Technology Corporation
Taipei Office (Marketing)
5F, No. 95, Minchiuan Road, Hsintien City
Taipei County, Taiwan, R.O.C.
Tel: (8862)86672399 Fax: (8862)86672377
Email: marketing@
Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit
design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be
guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek.
24
DS9986A-00 May 2011