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POWER MANAGEMENT

Single-Phase Single Chip

Vcore Power Supply

April 12, 2006

SC457

Applications

Description

Features

The SC457 is a single phase, high performance PWM con-

troller designed to power advanced processors. On-chip

support is provided for VID on-the-fly transitions and active

voltage positioning.

The SC457 implements hysteretic control technology

providing the fastest possible transient response while

avoiding the stability issues inherent to classical PWM

controllers. Eliminating the sense resistors reduces costs

and PCB area while increasing system efficiency. Integrated

SmartDriver™ technology initially turns on the high-side

driver with soft drive to reduce ringing, EMI, and capacitive

turn-on of the low side MOSFET, while increasing overall

efficiency.

Hysteretic operation adaptively reduces the SC457 switch-

ing frequency at light loads. Combined with an automatic

power-save mode which prevents negative current flow in

the low-side FET, system efficiency is significantly enhanced

during light loading conditions.

A 7-bit DAC, accurate to 0.85%, sets the output voltage

reference and implements the 0.300V to 1.500V range

required by the processor. The DAC slew rate is externally

programmed to minimize transient currents and audible

noise. True differential remote sensing provides accurate

point-of-load regulation at the processor die. Other features

include programmable soft-start, open-drain PG_DEL and

PG# outputs, dynamic current sharing, over-voltage and

programmable over-current protection. The SC457 is avail-

able in a space-saving 32-pin MLP package.

Single-Phase Solution with Integrated Drivers

Hysteretic Control for Fast Transient Response

Active Voltage Positioning

True Differential Remote (die) Sensing

On-Chip Support for all Power Management

Features

Programmable Soft-Start and DAC Slew Control

Programmable OCP Threshold

Supports all Ceramic Decoupling Solutions

32-Pin MLP (5x5) - product is WEEE and RoHS

compliant

Default 1.2V Boot Voltage

Soft OFF State

Notebook PCs

Embedded Applications

Graphics and other Processor Cores

NOT RECOMMENDED FOR NEW DESIGN