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SC2677B

Dual Synchronous Voltage Mode

Controller with Current Sharing Circuitry

POWER MANAGEMENT

Features

The SC2677B is a versatile 2 phase, synchronous, voltage

mode PWM controller that can be used in two distinct ways.

First, the SC2677B is ideal for applications where point of

use output power exceeds any single input power budget.

Alternatively, the SC2677B can be configured as a dual

switcher. The SC2677B features a precise temperature

compensated voltage reference, cycle-by-cycle peak cur-

rent limit, under voltage lockout over current protection,

and internal level-shifted high-side gate drive circuitry.

In current sharing configuration, the SC2677B can produce

a single output voltage from two separate input voltage

sources (which can be different in voltage levels) while

maintaining current sharing between the two channels.

Current sharing is programmable to allow each input sup-

ply to be loaded differently per application requirements.

In dual switcher configuration, two feedback paths are pro-

vided for independent control of the separate outputs. The

device will provide a regulated output from flexibly config-

ured inputs, such as 3.3V, 5V, 12V etc. The phasing be-

tween the two switchers is adjustable to minimize the input

and output ripple.

300kHz to 1MHz externally programmable

frequency operation

Soft Start and Enable function

Power Good output provided

Cycle-by-cycle peak current limit

Latch Off for over current protection

Phase-shifted switchers minimize ripple

High-efficiency operation, >90%

Programmable output(s) as low as 0.5V

Industrial temperature range

TSSOP-24 package

TSSOP-24 EDP package

Bias voltage as low as 4.5V

Adjustable phase shift between channels

Two Phase, Current Sharing Controller

Flexible, same or separate V

IN

Programmable current sharing

Thermal distribution via multi-phase output

Graphics cards

Peripheral add-in card

Dual-phase power supply

Power supplies requiring two outputs

CS1+

CS2+

C6

M5

C62

D1

CS1+

R20

C39

R49

R5

C63

M7

PW RGD

Vout2

R48

R21

D3

D2

C4

C25

M3

C38

CS2-

CS2-

R8

L1

1

2

D4

C36

C23

C19

CS1-

L2

1

2

U1

SC2677B

C26

R18

R19

C57

CS1-

R50

Vin

R10

C28

ENABLE

C33

Vout1

CS2+

R13

M1

R14

C43

C59

R51

Dual Independent outputs

Typical Application Schematic

Description

Applications

Revision: Dec. 15, 2004