Preliminary

RT9264

DS9264-00 December 2001

www.richtek-ic.com.tw

3

Pin Description

Pin No. Pin Name

Pin Function

1GND

Ground

2EXT

Output pin for driving external NMOS or NPN

When driving an NPN, a resistor should be added for limiting base current.

3LFB

Feedback pin of the built-in LDO (Internal Vref = 0.86V)

4LDOO

Voltage output pin of the built-in LDO

5FB

Feedback input pin

Internal reference voltage for the error amplifier is 1.25V.

6VDD

Input positive power pin of RT9264

7LX

Pin for switching

8CE

Chip enable

RT9264 gets into shutdown mode when CE pin set to low.

Function Block Diagram

EXT

LDOO

Loop Control Circuit

Over Temp.

Detector

LX

GND

Shut Down

1.25V

1.25V

RT9264

VDD

LFB

FB

CE

VDD

R2

Q3

NMOS

VDD

Q2

PMOS

R1

Q1

NMOS