Data Sheet

ADPL42002

analog.com

Rev. 1

14 of 22

APPLICATIONS INFORMATION

Design Tools

The ADPL42002 is supported by the LTpowerCAD® and LTspice® design tools to produce complete power designs and

simulations. For more information on design tools, visit the ADPL42002 product page, www.analog.com/ADPL42002.

Capacitor Selection

Output Capacitor

The ADPL42002 is designed for operation with small, space-saving ceramic capacitors, but functions with general-

purpose capacitors as long as care is taken with regard to the effective series resistance (ESR) value. The ESR of the

output capacitor affects the stability of the LDO control loop. A minimum of 2.2µF capacitance with an ESR of 0.3Ω

or less is recommended to ensure the stability of the ADPL42002. The transient response to changes in load current

is also affected by output capacitance. Using a larger value of output capacitance improves the transient response

of the ADPL42002 to large changes in load current. Figure 27 shows the transient responses for an output capacitance

value of 2.2µF.

Figure 27. Output Transient Response, VOUT = 5V, COUT = 2.2µF, CH1 Load Current, CH2 VOUT

Input Bypass Capacitor

Connecting a 2.2µF capacitor from VIN to GND reduces the circuit sensitivity to the PCB layout, especially when long

input traces or high source impedance is encountered. If greater than 2.2µF of output capacitance is required,

increase the input capacitor to match it.

Programable Precision Enable

The ADPL42002 uses the EN pin to enable and disable the VOUT pin under normal operating conditions. As shown in

Figure 28, when a rising voltage on EN crosses the upper threshold, nominally 1.2V, VOUT turns on. When a falling

voltage on EN crosses the lower threshold, nominally 1.1V, VOUT turns off. The hysteresis of the EN threshold is

approximately 100mV.

CH1 200mA Ω BW

M20µs

A CH1

100mA

T 10.2%

1

2

CH2 20mV

B

W

T