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SC450

Portable IMVP-IV™ and IMVP4+™

Dual Phase Power Supply Controller

POWER MANAGEMENT

Revision: May 21, 2004

Description

Features

Applications

Typical Application Circuit

solution

On chip CLK_ENABLE# and IMVP4_PWRGD outputs

Backward compatible with SC1476

High speed hysteretic controller

6 bit VID programmable output

Integrated drivers with soft high side turn-on

Programmable softstart

Programmable boot voltage

Programmable DeeperSleep voltage

Dynamic phase current matching

Under-voltage lockout 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

Slew rate limited DAC

TSSOP-38 package

The SC450 PowerStep IV™ IC is a single chip high-per-

formance Hysteretic PWM controller. With its integrated

SmartDriver™, it powers advanced IMVP-IV™ and

IMVP4+™ processors. The SC450 features extended Intel

Mobile Voltage Positioning (IMVP™) to increase battery

life by reducing the voltage at the processor when it is

heavily loaded. It directly supports Intel’s SpeedStep®

processors for even longer battery life. The SC450 fully

supports the Intel® Geyserville-III core voltage specifi-

cation. It provides direct “deeper sleep” mode and boot

voltage support. Automatic “power-save” 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

provides the fastest possible transient response, while

avoiding the stability issues inherent to classical PWM

controllers. The DAC is externally slew rate limited to mini-

mize transient currents and audible noise.

The SC450 operates from 3.3V and 5V. It also features

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

blanking, and an enable input. Programmable current

limiting shuts down the SC450 after 32 current limit

pulses. In addition, it comes in a space-saving TSSOP-

38 package.

SC1 474

D ualP hase

E x te nde d IMV P

CONT RO LLER

VID [4 :0 ]

Lo

+ V CORE

+V _IN

+V _ 5

0.600V -1 .75V

U p to 4 0 A

Exte nded

IMV P

Logic

PW M

Co ntro ller

Po w e r

C ontro l

Signa ls

Sm a rt

Drive r

VID

Mu ltiplexe r

Lo

Co

Sm a rt

Drive r

Rc s

Rc s

+V _ 3

+V _ V ID

VID

R egulator

Co ntro ller

SC1 474

D ualP hase

E x te nde d IMV P

CONT RO LLER

VID [4 :0 ]

Lo

+ V CORE

+V _IN

+V _ 5

0.600V -1 .75V

U p to 4 0 A

Exte nded

IMV P

Logic

PW M

Co ntro ller

Po w e r

C ontro l

Signa ls

Sm a rt

Drive r

VID

Mu ltiplexe r

Lo

Co

Sm a rt

Drive r

Rc s

Rc s

+V _ 3

+V _ V ID

VID

R egulator

Co ntro ller

VID[5:0]

VID[5:0]

VID[5:0]

VID[5:0]

VID[5:0]

Notebook and Laptop computers

Embedded applications

PowerStep IV™ and SmartDriver™ are trademarks of

Semtech Corporation.

Other trademarks or registered trademarks may be claimed

as the property of others.