APL3213 datasheet(10/15 Pages) ANPEC

10 / 15 page

Rev. A.3 - Aug., 2011

www.anpec.com.tw

APL3213/A

Application Information

Capacitor Selection

The input capacitor is for decoupling and prevents the

input voltage from overshooting to dangerous levels. In

the AC adapter hot plug-in applications or load current

step-down transient, the input voltage has a transient

spike due to the parasitic inductance of the input cable. A

25V, X5R, dielectric ceramic capacitor with a value be-

tween 1

µF and 4.7µF placed close to the ACIN pin is

recommended.

The output capacitor is for output voltage decoupling, and

also the input capacitor of the charging circuit.

At least, a 1

µF, 10V, X5R capacitor is recommended.

In some failure modes, a high voltage may be applied to

the device. Make sure the clearance constraint of the PCB

layout must satisfy the design rule for high voltage.

The exposed pad of the TDFN2x2-8 performs the func-

tion of channeling heat away. It is recommended that

connect the exposed pad to a large copper ground plane

on the backside of the circuit board through several ther-

mal vias to improve heat dissipation.

The input and output capacitors should be placed close

to the IC.

The high current traces like input trace and output trace

must be wide and short.

Layout Consideration

APL3213 Datasheet(PDF) 10 Page - Anpec Electronics Coropration