SC451 Datasheet, PDF(1/1 Page) Semtech Corporation – Portable IMVP-IV™ and IMVP-IV+™ Single Phase Power Supply Controller

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SC451 Datasheet, PDF (1/1 Pages) Semtech Corporation – Portable IMVP-IV™ and IMVP-IV+™ Single Phase Power Supply Controller

SC451

Portable IMVP-IVâ¢ and IMVP-IV+â¢

Single Phase Power Supply Controller

POWER MANAGEMENT

Description

Features

The SC451 PowerStep IVâ¢ IC is a single chip high-perfor-

mance Hysteretic PWM controller. With its integrated

SmartDriverâ¢, it powers advanced IMVP-IVâ¢ and IMVP4+â¢

processors. The SC451 features extended Intel Mobile Volt-

age Positioning (IMVPâ¢) to increase battery life by reduc-

ing the voltage at the processor when it is heavily loaded.

It directly supports Intelâs SpeedStepÂ® processors for even

longer battery life. The SC451 fully supports the IntelÂ®

Geyserville-III core voltage specification. It provides direct

âdeeper sleepâ mode and boot voltage support. Automatic

âpower-saveâ is present to prevent negative current flow in

the low-side FET during light loading conditions, saving even

more power. The high side driver initially turns on with a

weak drive to reduce ringing, EMI, and capacitive turn-on

of the low side.

A 6-bit DAC, accurate to 0.85%, sets the output voltage

reference, and implements the 0.700V to 1.708V range

required by the processor. The hysteretic converter uses a

comparator without an error amplifier, and therefore pro-

vides the fastest possible transient response, while avoid-

ing the stability issues inherent to classical PWM control-

lers. The DAC is externally slew rate limited to minimize

transient currents and audible noise.

The SC451 operates from 5VDC and also features soft-

start, an open-drain PWRGD signal with power-good blank-

ing, and an enable input. Programmable current limiting

shuts down the SC451 after 32 current limit pulses. It

comes in both a TSSOP-28 and TSSOP-38 package. The

TSSOP-38 provides a pin-to-pin upgrade to a dual-phase

solution using Semtechâs dual-phase controller, SC450.

! IMVP-IVâ¢ and IMVP-IV+â¢ compliant single chip

solution

! On-chip CLK_ENABLE# and IMVP4_PWRGD outputs

! Backward compatible with SC1479

! High-speed hysteretic controller

! Single-phase operation

! Selectable analog or VID controlled DeeperSleep

setting

! 6 bit VID programmable output

! Integrated drivers with soft high side turn-on

! Programmable softstart

! Programmable boot voltage

! Programmable DeeperSleep voltage

! Under-voltage lock out on VccA

! Over-voltage protection on CORE

! Current limit protection on CORE

! Thermal protection

! Powergood flag with blanking during VID or

DeeperSleep mode changes

! Automatic powersave at light load

! TSSOP-28 and TSSOP-38 package options

Applications

! Low power Notebook and Laptop computers

! Embedded Applications

PowerStep IVâ¢ is a trademark of Semtech

Corporation.

Other trademarks or registered trademarks may be

claimed as the property of others.

Conceptual Application Circuit

VCCA

Sm art

Driver

V IN

VCORE

0.700V -1.708V

June 6, 2005

V ID (5:0)

SC 451 Single P hase

IM VP-IV/IM VP-IV+

Pow er Supply

PWM

Contro ller

V ID Logic

and DAC