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SC2453

High Performance Quad Output

Switching Regulator

POWER MANAGEMENT

PRELIMINARY

Revision 5, August 2002

Description

Features

Applications

Typical Application Circuit

Two synchronized converters for low noise

Power up sequencing to prevent latch-ups

Out of phase operation for low input ripple

Over current protection

Wide input range, 4.5 to 30V

Programmable frequency up to 700KHz

Two synchronous bucks for high efficiency at high

current

One dedicated programmable positive linear

regulator and one dedicated programmable nega-

tive linear regulator

–40 to 105 degree C operating temperature

Output voltage as low as 0.5V

Small package TSSOP-28

SC2453 is a high performance multi-output converter

controller that can be configured for a variety of applica-

tions. The SC2453 utilizes synchronous rectified buck

topologies where efficiency is most important. It also

provides dedicated programmable positive and negative

linear regulators using external transistors in conjunction

with coupled windings to generate positive and negative

voltages. Power up sequencing prevents converter latch-

ups.

The two buck converters are out of phase, reducing in-

put ripple, allowing for fewer input capacitors. All con-

verters are synchronized to prevent beat frequencies.

High frequency operation will reduce ripple and minimize

noise. It also reduces the size of output inductors and

capacitors. Other features include soft start, power-good

signaling, bootstrapping for high side MOSFETs, and fre-

quency synchronization.

DSL applications with multiple input voltage re-

quirements

Mixed-Signal applications requiring positive and

negative voltages

Cable modem power management

Base station power management

R38

C29

C41

C30

Q11

Q1

D11

R28

C31

C31

R31

+8-30V

R33

SC2453

23

24

25

12

26

8

7

15

3

20

2

4

13

19

18

17

5

28

14

27

21

1

11

10

22

16

6

9

GD1L

PH1

GD1H

EO2

BST1

POK

SYNC/SHDN

AGND

EO1

GD2L

FB1

BD4

FB2

PH2

GD2H

BST2

FB4

BDI

ILIM2

VIN

PGND

ILIM1

BD3

FB3

PVCC

AVCC

SS

OSC

Q15

Q12

C29

C32

R28

C31

+3.3V

Q14

Q11

C32

R28

C30

R32

R31

R31

C32

C33

+3.3V

C32

R31

-12V

R32

R39

D11

R30

+3.3V

C29

C38

L8

R32

C34

R32

C32

R35

D10

+1.5V

Q2

+2.5V

C29

L9

C35

C42