AP7335 Datasheet, PDF (11/18 Pages) Diodes Incorporated – 300mA, Low Quiescent Current, Fast Transient Low Dropout Linear Regulator

AP7335
300mA, Low Quiescent Current, Fast Transient
Low Dropout Linear Regulator
Application Note
Input Capacitor
A 1μF 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 1μF 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.
Region of Stable C_OUT ESR vs. Load Current
100
Unstable Range
10
1
Stable Range
0.1
V_IN=4.3V
C_IN=C_OUT=1μF
0.01
0.001
0
Unstable Range
50 100 150 200 250 300
Load Current (mA)
AP7335
Document number: DS32259 Rev. 1 - 2
11 of 18
www.diodes.com
July 2010
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