LM39302中文资料-USB迷|专注于互联网分享

2024年4月17日发(作者：碧高歌)

Storage Temperature (TS) : –65°C to +150°C Lead Temperature (soldering, 5 sec) : 260°C ESD, Note 3

Operating Ratings (Note 2)

Supply Voltage (VIN) : +2.25V to +16V Enable Voltage (VEN) : +16V

Maximum Power Dissipation (PD(max)) Note 4 Junction Temperature (TJ) : –40°C to +125°C Package Thermal Resistance

TO-263(θJC

) : 2°C/W

TO-220(θJC

) : 2°C/W

LM39300

LM39301

LM39302

Block Diagram

LM39300 Fixed (1.5V,1.8V,2.5V,3.3V,5.0V)

LM39301 Fixed with Flag and Enable

LM39302 Adjustable

550

Note 1. Exceeding the absolute maximum ratings may damage the device.

Note 2. The device is not guaranteed to function outside its operating rating.

Note 3. Devices are ESD sensitive. Handling precautions recommended.

Note 4. P D(max) = (T J(max) – T A) θJA, where θJA depends upon the printed circuit layout. See “Applications

Information.”Note temperature coefficient is ?V OUT(worst case) (T J(max) – T J(min)) where T J(max) is +125℃ and

T J(min) is 0℃Note 6. V DO = V IN – V OUT when V OUT decreases to 99% of its nominal output voltage with V IN = V OUT

+ 1V.

Note 7. I GND is the quiescent current. IIN = I GND + I OUT.

Note 8. V EN 0.8V, V IN 8V, and V OUT = 0V

Note 9. For a 2.5V device, V IN = 2.250V (device is in dropout).

Note ≤ VOUT ≤ (VIN – 1V), 2.25V ≤ VIN ≤ 16V, 10mA ≤ IL ≤ 1A, TJ = TMAX.

TYPICAL PERFORMANCE CHARACTERISTICS

APPLICATION INFORMATION

The LM39300/1 is a high-performance low-dropout voltage regulator suitable for moderate to high-current voltage regu-lator

applications. Its 500mV dropout voltage at full load makes it especially valuable in battery-powered systems and as a high-

efficiency noise filter in post-regulator applications. Unlike older NPN-pass transistor designs, where the mini-mum dropout

voltage is limited by the base-to-emitter voltage drop and collector-to-emitter saturation voltage, dropout per-formance of the

PNP output of these devices is limited only by the low V CE saturation voltage.A trade-off for the low dropout voltage is a

varying base drive requirement. The LM39300/1/2 regulator is fully protected from damage due to fault conditions. Current

limiting is provided. This limiting is linear output current during overload conditions is constant. Thermal shutdown disables

the device when the die temperature exceeds the maximum safe operating tem-perature. Transient protection allows device

(and load) sur-vival even when the input voltage spikes above and below nominal. The output structure of these regulators

allows voltages in excess of the desired output voltage to be applied without reverse current flow.

Thermal Design

Linear regulators are simple to use. The most complicated design parameters to consider are thermal l

design requires four application-specific param-eters:

Maximum ambient temperature (T A)

Output Current (I OUT)

Output Voltage (V OUT)

Input Voltage (V IN)

Ground Current (I GND)

Calculate the power dissipation of the regulator from these numbers and the device parameters from this datasheet,where

the ground current is taken from the data sheet.

PD = (V IN – V OUT) I OUT + V IN·I GND

The heat sink thermal resistance is determined by:

θSA=(T JMAX-T A)/P D -(θJC+θCS)

where TJ (max) 125 ℃ and θCS is between 0℃ and 2℃/W.

The heat sink may be significantly reduced in applications where the minimum input voltage is known and is large compared

with the dropout voltage. Use a series input resistor to drop excessive voltage and distribute the heat between this resistor

and the regulator. The low dropout properties of Taejin regulators allow signifi-cant reductions in regulator power dissipation

and the asso-ciated heat sink without compromising performance. When this technique is employed, a capacitor of at least

1.0F is needed directly between the input and regulator to Application Note 9 for further details and examples

on thermal design and heat sink specification.

Output Capacitor

The LM39300/1/2 requires an output capacitor to maintain stability and improve transient response. Proper capacitor

selection is important to ensure proper operation. The LM39300/1/2 output capacitor selection is dependent upon the ESR

(equivalent series resistance) of the output capacitor to maintain stability. When the output capacitor is 47F or greater, the

output capacitor should have less than 1 of ESR. This will improve transient response as well as promote stability. Ultralow

ESR capacitors, such as ceramic chip capacitors may promote instability. These very low ESR levels may cause an

oscillation and/or underdamped tran-sient response. A low-ESR solid tantalum capacitor works extremely well and provides

good transient response and stability over temperature. Aluminum electrolytics can also be used, as long as the ESR of the

capacitor is < value of the output capacitor can be increased without limit. Higher capacitance values help to improve

transient response and ripple rejection and reduce output noise. Input Capacitor

An input capacitor of 1F or greater is recommended when the device is more than 4 inches away from the bulk ac supply

capacitance, or when the supply is a battery. Small, surface-mount, ceramic chip capacitors can be used for the bypass-ing.

Larger values will help to improve ripple rejection by bypassing the input to the regulator, further improving the integrity of the

output ent Response and 3.3V.

Fig 1. Capacitor Requirements

Minimum Load Current

The LM39300/1/2 regulator is specified between finite loads.

If the output current is too small, leakage currents dominate and the output voltage rises.

A 10mA minimum load current is necessary for proper regulation.

Transient Response and 3.3V to 2.5V Conversion

The LM39300/1/2 has excellent transient response to varia-tions in input voltage and load current. The device has been

designed to respond quickly to load current variations and input voltage variations. Large output capacitors are not required

to obtain this performance. A standard 47F output capacitor, preferably tantalum, is all that is required. Larger values help to

improve performance even virtue of its low-dropout voltage, this device does not saturate into dropout as readily as

similar NPN-based de-signs. When converting from 3.3V to 2.5V, the NPN-based regulators are already operating in

dropout, with typical dropout requirements of 1.2V or greater. To convert down to 2.5V without operating in dropout, NPN-

based regulators require an input voltage of 3.7V at the very least. The

LM39300/1/2 regulator will provide excellent performance with an input as low as 3.0V. This gives the PNP-based regulators

a distinct advantage over older, NPN-based linear regulators.

Error Flag

The LM39301 version features an error flag circuit which monitors the output voltage and signals an error condition when the

voltage drops 5% below the nominal output voltage. The error flag is an open-collector output that can sink 10mA during a

fault output voltage can be caused by a number of problems, including an overcurrent fault (device in current

limit) or low input voltage. The flag is inoperative during overtemperature shutdown.

Enable Input

The LM39301 version features an enable input for on/off control of the device. Its shutdown state draws “zero” current (only

microamperes of leakage). The enable input is TTL/ CMOS compatible for simple logic interface, but can be connected to up

to 20V. When enabled, it draws approxi-mately 15A.

Adjustable Regulator Design

The LM39302 allows programming the output voltage any-where between 1.25V and the 16V maximum operating rating of

the family. Two resistors are used. Resistors can be quite large, up to 1M?, because of the very high input impedance and

low bias current of the sense comparator: The resistor values are calculated by :R1=R2(Vout/1.250-1)

Where VO is the desired output voltage. Figure 1 shows component definition. Applications with widely varying load currents

may scale the resistors to draw the minimum load current required for proper operation (see below).