AP7335

300mA, Low Quiescent Current, Fast Transient

Low Dropout Linear Regulator

AP7335

Document number: DS32259 Rev. 1 - 2

11 of 18

www.diodes.com

July 2010

© Diodes Incorporated

Application Note

Input Capacitor

A 1

μF ceramic capacitor is recommended between IN and GND pins to decouple input power supply glitch and

noise. The amount of the capacitance may be increased without limit. This input capacitor must be located as

close as possible to the device to assure input stability and reduce noise. For PCB layout, a wide copper trace is

required for both IN and GND pins. A lower ESR capacitor type allows the use of less capacitance, while higher

ESR type requires more capacitance.

Output Capacitor

The output capacitor is required to stabilize and improve the transient response of the LDO. The AP7335 is stable

with very small ceramic output capacitors. Using a ceramic capacitor value that is at least 1

μF with ESR > 15mΩ

on the output ensures stability. Higher capacitance values help to improve line and load transient response. The

output capacitance may be increased to keep low undershoot and overshoot. Output capacitor must be placed as

close as possible to OUT and GND pins.

0.001

0.01

0.1

1

10

100

0

50

100

150

200

250

300

Load Current (mA)

Unstable Range

Stable Range

Unstable Range