1

®

FN9059.2

ISL6557

Multi-Phase PWM Controller for

Core-Voltage Regulation

The ISL6557 provides core-voltage regulation by driving up

to four interleaved synchronous-rectified buck-converter

channels in parallel. Intersil multi-phase controllers together

with Intersil MOSFET drivers form the basis for the most

reliable power-supply solutions available to power the latest

industry-leading microprocessors. Multi-phase buck-

converter architecture uses interleaved timing to multiply

ripple frequency and reduce input and output ripple currents.

Lower ripple results in lower total component cost, reduced

dissipation, and smaller implementation area. Pre-

configured for 4-phase operation, the ISL6557 offers the

flexibility of selectable 2- or 3-phase operation. Simply

connect the unused PWM pins to VCC. The channel

switching frequency is adjustable in the range of 50kHz to

1.5MHz giving the designer the ultimate flexibility in

managing the balance between high-speed response and

good thermal management.

New features on the ISL6557 include Dynamic-VID™

technology allowing seamless on-the-fly VID changes with

no need for any additional external components. When the

ISL6557 receives a new VID code, it incrementally steps the

output voltage to the new level. Dynamic VID changes are

fast and reliable with no output voltage overshoot or

undershoot. The RGND and VSEN pins provide inputs for

differential remote voltage sensing to improve regulation and

protection accuracy. A threshold-sensitive enable pin (EN)

can be used with an external resistor divider to optionally set

the power-on voltage level. This allows optional start-up

coordination with Intersil MOSFET drivers or any other

devices powered from a separate supply.

Like other Intersil multiphase controllers, the ISL6557 uses

cost and space-saving

balance, dynamic voltage positioning, and overcurrent

protection. Channel current balancing is automatic and

accurate with the integrated current-balance control system.

Overcurrent protection can be tailored to any application with

no need for additional parts. The IOUT pin carries a signal

proportional to load current and can be optionally connected

to FB for accurate load-line regulation.

An integrated DAC decodes the 5-bit logic signal present at

VID4-VID0 and provides an accurate reference for precision

voltage regulation. The high-bandwidth error amplifier,

differential remote-sensing amplifier, and accurate voltage

reference all work together to provide better than 0.8% total

system accuracy, and to enable the fastest transient

response available.

Features

• Multi-Phase Power Conversion

• Active Channel Current Balancing

• Precision

-Low Cost

- Lossless

• Precision CORE Voltage Regulation

- Differential Remote Voltage Sensing

-

±0.8% System Accuracy

• Microprocessor Voltage Identification Input

- Dynamic VID technology

- 5-Bit VID Input

- 1.100V to 1.850V in 25mV Steps

• Programmable Power-On Bias Level

• Programmable Droop Voltage

• Fast Transient Recovery Time

• Precision Enable Threshold

• Overcurrent Protection

• 2-, 3-, or 4-Phase Operation

• High Ripple Frequency. Channel Frequency Times

Number Channels (100kHz to 6MHz)

Pinout

ISL6557 24 PIN (SOIC)

TOP VIEW

Ordering Information

PART NUMBER

PACKAGE

PKG. DWG. #

ISL6557CB

0 to 70

24-Ld SOIC

M24.3

ISL6557CB-T

24-Ld SOIC Tape and Reel

VID4

VID3

VID2

VID1

VID0

IOUT

PWM2

PGOOD

PWM3

ISEN4

ISEN1

VDIFF

ISEN3

FB

PWM4

VSEN

COMP

PWM1

ISEN2

RGND

GND

FS

EN

VCC

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

Data Sheet

August 2003

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 321-724-7143

Copyright © Intersil Americas Inc. 2003. All Rights Reserved.

All other trademarks mentioned are the property of their respective owners. Dynamic VID™ is a trademark of Intersil Americas Inc.