3

FN7435.7

December 8, 2006

Block Diagram

Pin Descriptions

PIN NUMBER

PIN NAME

PIN FUNCTION

1

SGND

Negative supply for the controller stage

2

PGND

Negative supply for the power stage

3

LX

Inductor drive pin; high current digital output with average voltage equal to the regulator output voltage

4

VIN

Positive supply for the power stage

5

VDD

Power supply for the controller stage

6

RSI

Resets POR timer; Connect to ground if not used

7

EN

Enable; Can be connected directly to the VIN for enable

8

POR

Power on reset open drain output; Leave open if not used

9

VO

Output voltage sense pin

10

FB

output

-

+

-

+

-

+

CONTROL

LOGIC

PWM

COMPEN-

SATION

POR

CLOCK

1.5MHz

SOFT-

START

BANDGAP

REFERENCE

TEMPERATURE

SENSE

+

–

LX

PGND

POR

FB

EN

SGND

10pF

5M

124K

100K

10µF

2.5V-

5V

EN

PWM

COMPARATOR

N-DRIVER

P-DRIVER

CURRENT

LIMIT

1.8µ

10µF

100K

PG

1.8V

2A

RSI

RAMP

GENERATOR

UNDER-

VOLTAGE

LOCKOUT

1

2

5

9

10

7

6

4

3

8

EL7532