General Description

The MAX1937/MAX1938/MAX1939 comprise a family of

synchronous, two-phase, step-down controllers capable

of delivering load currents up to 60A. The controllers uti-

lize Quick-PWM™ control architecture in conjunction with

active load-current voltage positioning. Quick-PWM con-

trol provides instantaneous load-step response, while

programmable voltage positioning allows the converter

to utilize full transient regulation limits, reducing the out-

put capacitance requirement. The two phases operate

180° out-of-phase with an effective 500kHz switching fre-

quency, thus reducing input and output current ripple, as

well as reducing input filter capacitor requirements.

The MAX1937/MAX1938/MAX1939 are compliant with

AMD Hammer, Intel

‚ Voltage-Regulator Module (VRM)

9.0/9.1, and AMD Athlon™ Mobile VID code specifica-

tions (see Table 1 for VID codes). The internal DAC pro-

vides ultra-high accuracy of ±0.75%. A controlled VID

voltage transition is implemented to minimize both

undervoltage and overvoltage overshoot during VID

input change.

Remote sensing is available for high output-voltage

accuracy. The MOSFET switches are driven by a 6V

gate-drive circuit to minimize switching and crossover

conduction losses to achieve efficiency as high as

90%. The MAX1937/MAX1938/MAX1939 feature cycle-

by-cycle current limit to ensure that the current limit is

not exceeded. Crowbar protection is available to pro-

tect against output overvoltage.

Applications

Notebook and Desktop Computers

Servers and Workstations

Blade Servers

High-End Switches

High-End Routers

Macro Base Stations

Features

o ±0.75% Output Voltage Accuracy

o Instant Load-Transient Response

o Up to 90% Efficiency Eliminates Heatsinks

o Up to 60A Output Current

o 8V to 24V Input Range

o User-Programmable Voltage Positioning

o Controlled VID Voltage Transition

o 500kHz Effective Switching Frequency

o MAX1937: AMD Hammer Compatible

o MAX1938: Intel VRM 9.0/9.1 Compatible

o MAX1939: AMD Athlon Mobile Compatible

o Soft-Start

o Power-Good (PWRGD) Output

o Cycle-by-Cycle Current Limit

o Output Overvoltage Protection (OVP)

o Remote Voltage Sensing

o 28-Pin QSOP Package

Two-Phase Desktop CPU Core Supply Controllers

with Controlled VID Change

________________________________________________________________ Maxim Integrated Products

1

28

27

26

25

24

23

22

21

20

19

18

17

16

15

1

2

3

4

5

6

7

8

9

10

11

12

13

14

BST1

DH1

LX1

CS1

DL1

PWRGD

VLG

PGND

DL2

CS2

LX2

DH2

BST2

FB

EN

REF

GNDS

GND

ILIM

VPOS

VID4

VID3

VID2

TIME

VID1

VID0

QSOP

TOP VIEW

MAX1937

MAX1938

MAX1939

Pin Configuration

Ordering Information

19-2498; Rev 1; 10/02

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

PART

TEMP RANGE

PIN-PACKAGE

MAX1937EEI

-40

°C to +85°C

28 QSOP

MAX1938EEI

-40

°C to +85°C

28 QSOP

MAX1939EEI

-40

°C to +85°C

28 QSOP

Quick-PWM is a trademark of Maxim Integrated Products, Inc.

Athlon is a trademark of Advanced Micro Devices, Inc.

Intel is a registered trademark of Intel Corp.

Typical Application Circuits and Functional Diagram appear

at end of data sheet.