RT9267

Preliminary

2

DS9267-08

March 2007

www.richtek.com

Typical Application Circuit

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

LX1

The Switching Pin for 1

st

PWM Converter

2

EN1

Enable Pin for 1

st

PWM Converter and LDO. (Active High)

3

GND

Ground (Both Pin3 and Pin8 should be connected)

4

EN2

Enable Pin for 2

nd

PWM Converter and Voltage Detector. (Active High)

5

NC

Not Connected

6

LX2

The Switching Pin for 2

nd

PWM Converter

7

NC

Not Connected

8

GND

Ground (Both Pin3 and Pin8 should be connected)

9

LBO

NMOS Open Drain Output of the Voltage Detector. This pin will internally pulled low when

the voltage at LBI pin below 0.86V.

10

LBI

Input Pin for Voltage Detector. The trip point is 0.86V.

11

FB2

Feedback Input Pin for 2

nd

12

LDOO

Voltage Output Pin for the LDO.

13

NC

Not Connected

14

LFB

15

FB1

Feedback Input Pin for 1

st

16

VDD

Input Positive Power Pin of RT9267, and also the Voltage Input Pin for LDO.

CE1

CE2

LDOO

LFB

VDD

LX1

FB1

LX2

RT9267

2

1

15

14

12

4

LBI

LBO

NC

NC

NC

FB2

GND

GND

6

11

10

9

5

7

13

83

16

R5

R6

1.6M

980k

C4

100pF

C6

100uF

C7

1uF

D1

D2

L1

L2

10uH

4.7uH

C10

100uF

Q1

N MOS

R7

R8

1.5M

112k

C5

0.1uF

R1

R2

1.3M

680k

C3

100pF

C2

10uF

C1

1uF

R4

R3

2.5V

C8

100uF

C9

1uF

1N5819

1N5819

3.3V

18V

V

Low Battery

Warning Output

(Poen Collector)

Chip Enable