General Description

The MAX8664 dual-output PWM controller is a low-cost,

high-performance solution for systems requiring dual

power supplies. It provides two individual outputs that

operate 180° out-of-phase to minimize input current

ripple, and therefore, capacitance requirements. Built-in

drivers are capable of driving external MOSFETs to

deliver up to 25A output current from each channel.

The MAX8664 operates from a 4.5V to 28V input volt-

age source and generates output voltages from 0.6V

up to 90% of the input voltage on each channel. Total

output regulation error is less than ±0.8% over load,

line, and temperature.

The MAX8664 operates with a constant switching fre-

quency adjustable from 100kHz to 1MHz. Built-in boost

diodes reduce external component count. Digital soft-

start eliminates input inrush current during startup. The

second output has an optional external REFIN2, facili-

tating tracking supply applications. Each output is

capable of sourcing and sinking current, making the

device a great solution for DDR applications.

The MAX8664 employs Maxim’s proprietary peak volt-

age-mode control architecture that provides superior

transient response during either load or line transients.

This architecture is easily stabilized using two resistors

and one capacitor for any type of output capacitors. Fast

transient response requires less output capacitance,

consequently reducing total system cost. The MAX8664B

latches off both controllers during a fault condition, while

the MAX8664A allows one controller to continue to func-

tion when there is a fault in the other controller.

Applications

Desktop and Notebook PCs

Graphic Cards

ASIC/CPU/DSP Power Supplies

Set-Top Box Power Supply

Printer Power Supply

Network Power Supply

POL Power Supply

Features

o ±0.8% Output Accuracy Over Load and Line

o Operates from a Single 4.5V to 28V Supply

o Simple Compensation for Any Type of Output

Capacitor

o Internal 6.5V Regulator for Gate Drive

o Integrated Boost Diodes

o Digital Soft-Start Reduces Inrush Current

o 100kHz to 1MHz Adjustable Switching

o 180° Out-of-Phase Operation Reduces Input

Ripple Current

o Overcurrent and Overvoltage Protection

o External Reference Input for Second Controller

o Prebiased Startup Operation

Low-Cost, Dual-Output, Step-Down

Controller with Fast Transient Response

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Maxim Integrated Products

1

Ordering Information

19-0796; Rev 0; 4/07

For pricing delivery, and ordering information please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

Note: This device operates over the -40°C to +85°C operating

temperature range.

+

Denotes lead-free package.

Pin Configuration appears at end of data sheet.

PART

PIN-

PACKAGE

PKG

CODE

FAULT

ACTION

MAX8664AEEP+

20 QSOP

E20-1

Independent

MAX8664BEEP+

20 QSOP

E20-1

Joint

DH1

BST1

DL1

BST2

FB2

FB1

LX1

PGND

DH2

LX2

DL2

GND

IN1

OUT2

IN2

OSC/EN12

ILIM2

PWRGD

REFIN2

IN

ILIM1

VL

MAX8664

OUT1

Typical Operating Circuit