LP38855-x.x

GND

OUT

IN

BIAS

EN

Under-Voltage

Lock-Out

Thermal

Shut Down

1.2V

Enable

VREF

0.6V

ILIMIT

LP38855

www.ti.com

SNVS461D – OCTOBER 2006 – REVISED APRIL 2013

Block Diagram

APPLICATION INFORMATION

EXTERNAL CAPACITORS

To assure regulator stability, capacitors are required on the input, output and bias pins as shown in the Typical

Application Circuit.

Output Capacitor

A minimum output capacitance of 10 µF, ceramic, is required for stability. The amount of output capacitance can

be increased without limit. The output capacitor must be located less than 1 cm from the output pin of the IC and

returned to the device ground pin with a clean analog ground.

Only high quality ceramic types such as X5R or X7R should be used, as the Z5U and Y5F types do not provide

sufficient capacitance over temperature.

Tantalum capacitors will also provide stable operation across the entire operating temperature range. However,

the effects of ESR may provide variations in the output voltage during fast load transients. Using the minimum

recommended 10 µF ceramic capacitor at the output will allow unlimited capacitance, Tantalum and/or

Aluminum, to be added in parallel.

Input Capacitor

The input capacitor must be at least 10 µF, but can be increased without limit. It's purpose is to provide a low

source impedance for the regulator input. A ceramic capacitor, X5R or X7R, is recommended.

Tantalum capacitors may also be used at the input pin. There is no specific ESR limitation on the input capacitor

(the lower, the better).

Aluminum electrolytic capacitors can be used, but are not recommended as their ESR increases very quickly at

cold temperatures. They are not recommended for any application where the ambient temperature falls below

0°C.

Copyright © 2006–2013, Texas Instruments Incorporated

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