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POWER MANAGEMENT

SC191

Low Supply Ripple Synchronous

Buck Conversion Regulator

April 12, 2006

Description

Features

Features

Typical Application Circuit

Applications

The SC191 is a synchronous step-down converter with

integrated power devices and an integrated front-end

LDO regulator to minimize input supply ripple. If supply

ripple is not a concern, the front-end LDO regulator can be

bypassed externally to maximize efficiency.

The internal MOSFET switches provide peak current greater

than 550mA to achieve a DC output of at least 330mA over

the rated input voltage range, making the SC191 ideal for

single-cell Li-ion battery applications as well as fixed 3.3V

and 5V fixed input applications. The output is a fixed 1.2V

- ideal for low-voltage microprocessors. Other voltage

options are available (consult the factory for details).

Additional features include internal soft-start to limit in-

rush current, over-current protection, over-temperature

protection, and over-voltage protection.

The 1MHz switching frequency allows the use of small

surface mount capacitors and inductors, and no other

external compensation components are needed. The

device is available in a low profile (0.8mm max height)

2.3mm x 2.3mm MLPD 8-lead package, minimizing area

without compromising performance.

Less than 1mV Supply Ripple

2.7V to 5.5V Input Range

330mA Guaranteed Output Current

Fixed Frequency 1MHz Operation

No Schottky Diode Required

Over-Current Protection

Over-Voltage Protection

Over-Temperature Protection

Soft-Start

No External Compensation Required

MLPD-8, 2.3mm x 2.3mm Package

WEEE and RoHS Compliant

Cell Phones

Cordless Phones

Notebook and Subnotebook Computers

PDAs and Mobile Communicators

WLAN Peripherals

Wireless Modules

1 Li-Ion or 3 NiMH/NiCd Powered Devices

SC191

L

4.7μH

4.7μF

VIN

VOUT

BP

GND

LX

PVIN

PGND

4.7μF

EN

4.7μF

1

5

8

6

3

4

2

7

Patent Pending