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SC4607

Very Low Input, MHz Operation,

High Efficiency Synchronous Buck

POWER MANAGEMENT

Revision: June 1, 2005

Description

Features

Applications

Typical Application Circuit

Asynchronous start up

BiCMOS voltage mode PWM controller

Operation of frequency to 1MHz

2.25V to 5.5V input voltage range

Output voltages as low as 0.5V

+/-1% reference accuracy

Sleep mode (Icc = 10µA typ)

Adjustable lossless short circuit current limiting

Combination pulse by pulse & hiccup mode

current limit

High efficiency synchronous switching

Up to 97% duty cycle

1A peak current driver

10-pin MSOP package

Distributed power architecture

Servers/workstations

Local microprocessor core power supplies

DSP and I/O power supplies

Battery-powered applications

Telecommunications equipment

Data processing applications

The SC4607 is a voltage mode step down (buck) regula-

tor controller that provides accurate high efficiency power

conversion from an input supply range of 2.25V to 5.5V.

The SC4607 is capable of producing an output voltage

as low as 0.5V and has a maximum duty cycle of 97%. A

high level of integration reduces external component

count, and makes it suitable for low voltage applications

where cost, size, and efficiency are critical.

The SC4607 drives external, N-channel MOSFETs with a

peak gate current of 1A. The SC4607 prevents shoot

through currents by offering nonoverlap protection for

the gate drive signals of the external MOSFETs. The

SC4607 features lossless current sensing of the voltage

drop across the drain to source resistance of the high

side MOSFET during its conduction period.

The quiescent supply current in sleep mode is typically

lower than 10µA. A 1.2ms soft start is internally provided

to prevent output voltage overshoot during start-up.

The SC4607 is an ideal choice for converting 2.5V, 3.3V,

5V or other low input supply voltages. It’s available in 10

pin MSOP package

*External components can be modified to provide a Vout as low as 0.5V

R3

C3

4.7u

C2 2.2n

C6

330u

R1

14.3k

C1

180p

C14

0.1u

Vin = 2.25V - 5.5V

R6

0

R5

0

D2

L1

1.8u

C5

22u

C4

22u

Vout = 1.5V (as low as 0.5V * ) / 12A

C71

1u

M1

C10

220u

M2

C12

22u

C9

4.7n

R8

200

R7

10k

R9

4.99k

C20

560pF

VCC

2

ISET

3

COMP

4

FS/SYNC

5

BST

1

DRVH

10

DRVL

8

VSENSE

6

GND

7

PHASE

9

U1

SC4607

C11

22u

R13

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