APL3526 datasheet(7/14 Pages) ANPEC

7 / 14 page

Rev. A.4 - Aug., 2013

www.anpec.com.tw

APL3526/B

Function Description

VIN Under-voltage Lockout (UVLO)

A under-voltage lockout (UVLO) circuit monitors the VBIAS

pins voltage to prevent wrong logic controls. The UVLO

function initiates a soft-start process after the BIAS sup-

ply voltages exceed rising UVLO voltage threshold dur-

ing powering on.

Power Switch

The power switch is an N-channel MOSFET with a ultra-

low R

DS(ON). When IC is in shutdown state (VEN=Low or

ENB=High), the MOSFET prevents a reverse current flow-

ing from the VOUT back to VIN. When IC is in UVLO state,

the internal parasitic diodes connected from VOUT to VIN

will be forward biased.

Soft-start

The APL3526/B Provides an adjustable soft-start circuitry

to control rise rate of the output voltage and limit the cur-

rent surge during start-up. The soft-start time is set with a

capacitor from the SS pin to the ground.

Enable Control

Pulling the ENB above 1.2V or EN below 0.4V will disable

the device, and pulling ENB pin below 0.4V or EN above

1.2V will enable the device. The EN/ENB pins cannot be

left floating.

Over-Temperature Protection (OTP)

When the junction temperature exceeds 160oC, the inter-

nal thermal sense circuit turns off the power FET and

allows the device to cool down. When the device’s junc-

tion temperature cools by 40oC, the internal thermal

sense circuit will enable the device, resulting in a pulsed

output during continuous thermal protection. Thermal

protection is designed to protect the IC in the event of

over temperature conditions. For normal operation, the

junction temperature cannot exceed T

J=+125

oC.

APL3526 Datasheet(PDF) 7 Page - Anpec Electronics Coropration