1

www.semtech.com

POWER MANAGEMENT

SC2647

Multi-Platform

Multi-Phase PWM Controller

July, 12, 2006

Description

Applications

The SC2647 provides microprocessor core voltage

regulation solution up to 4 paralleled PWM channels. The

solution can also be configured as 2, 3, or 4-phase form.

Multi-phase buck regulator utilizes the phase-shift tim-

ing control to allow interleaved switching of the power

switches. This architecture minimizes the core voltage

ripple and the input current ripple, which leads to opti-

mized voltage regulator design for power density, tran-

sient responses, and the thermal performances.

To satisfy the highly dynamic nature of the modern

microprocessors, the SC2647 adopts peak current mode

control topology which ensures wide control loop

bandwidth and fast transient responses. The current

mode control provides intrinsic phase current matching.

The maximum ripple frequency is greater than 1MHz.

One of the outstanding features of the SC2647 is its

voltage regulation accuracy. Not only it provides better

than 0.5% set point accuracy, but also the accuracy to

fully complaint with the stringent load line slope

specifications mandated by the modern microprocessors.

Lossless output current sensing ensures the regulator

output voltage is accurately positioned according to the

load current condition, and an internal temperature

compensation technology further enhances the perfor-

mance of voltage accuracy.

SC2647. The MOSFET R

winding resistance is used to generate the phase cur-

driver plus the SC2647 enables the complete solution.

The SC2647 is a multi-platform controller. It conforms

VID specifications. With very minor changes of the sche-

matic and the layout, the SC2647 based solution can be

ported form one platform to another. This greatly ben-

efits the system manufactures for reductions of design

cycle and minimize the inventory management.

VRD/VRM10.0, VRM9.X, and K-8 compliant

Core Voltage Set Point Accuracy 0.5%

Intrinsic Phase Current Matching

Fast Transient Responses

Active Droop with Temperature Compensation to

Meet Load Line Slope

Support VID-on-Fly with 5 or 6 bit VID

Enable Function for Power Sequencing

Cycle-by-Cycle Peak Current Limit

Intelligent Over Current Shut Down

Over Voltage Protection When Using Semtech

Under Voltage Protection Built in

External programmable Soft-Start

Externally programmable switching frequency.

2, 3, or 4-Phase Configurations

24-Pin SOIC or TSSOP Packages

This device is fully WEEE and RoHS Compliant

Voltage Regulator VRD/VRM10.0

Voltage Regulator VRM9.X

Voltage Regulator K-8

High Current, Low Voltage Step Down DC/DC

Converters

Features

The VID structure of the SC2647 supports VID-on-Fly ap-

plications for any platform. The cycle-by-cycle current

limit plus the intelligent over current shut down provide

the maximum versatility of the system without false

tripping under all possible changes of VID and load

conditions. The differential voltage feedback sense

eliminates the error caused by high load current on the

ground plane. External offset is easy to achieve for any

platforms and the VID settings. The enable function is

also provided to interface with the corresponding sys-

tem signal for correct start up timing and shut down

timing.

(Multiple Patents Pending)

(Multiple Patents Pending)

(Multiple Patents Pending)

(Multiple Patents Pending)

(Multiple Patents Pending)