AP7361_17 Datasheet, PDF (12/22 Pages) Diodes Incorporated – 1A LOW DROPOUT ADJUSTABLE AND FIXED-MODE REGULATOR WITH ENABLE

AP7361
Application Information
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 a higher ESR type requires more capacitance.
Output Capacitor
The output capacitor is required to stabilize and improve the transient response of the LDO. The AP7361 is stable with very small ceramic output
capacitors. Using a ceramic capacitor value that is at least 2.2μF with 10mΩ ≦ ESR ≦ 300mΩ 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.
Adjustable Operation
Adjustable operation is not available in the SOT223 TO252 and SO-8EP package. The AP7361 provides output voltage from 0.8V to 5.0V through
external resistor divider as shown below.
VIN
IN
OUT
AP7361
R1
1uF
Enable _EN
ADJ
GND
R2
VOUT
4.7uF
Adjustable Output
The output voltage is calculated by:
VOUT
 VREF _{}1
R₁
R₂

Where VREF = 0.8V (the internal reference voltage)
Rearranging the equation will give the following that is used for adjusting the output to a particular voltage:
R₁

R_{2}
VOUT
VREF
 1_{}
To maintain the stability of the internal reference voltage, R2 need to be kept smaller than 80kΩ.
AP7361
Document number: DS33626 Rev. 11 - 3
12 of 22
www.diodes.com
March 2017
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