__________________General Description

The MAX786 is a system-engineered power-supply

controller for notebook computers or similar battery-

powered equipment. It provides two high-performance

step-down (buck) pulse-width modulators (PWMs)

for +3.3V and +5V. Other features include dual,

low-dropout, micropower linear regulators for

CMOS/RTC back-up, and two precision low-battery-

detection comparators.

High efficiency (95% at 2A; greater than 80% at loads

from 5mA to 3A) is achieved through synchronous recti-

fication and PWM operation at heavy loads, and

Idle Mode

physically small components, thanks to high operating

frequencies (300kHz/200kHz) and a new current-mode

PWM architecture that allows for output filter capacitors

as small as 30µF per ampere of load. Line- and load-

transient responses are terrific, with a high 60kHz unity-

gain crossover frequency allowing output transients to

be corrected within four or five clock cycles. Low sys-

tem cost is achieved through a high level of integration

and the use of low-cost, external N-channel MOSFETs.

Other features include low-noise, fixed-frequency PWM

operation at moderate to heavy loads, and a synchro-

nizable oscillator for noise-sensitive applications such

as electromagnetic pen-based systems and communi-

cating computers. The MAX786 is a monolithic,

BiCMOS IC available in fine-pitch, surface-mount

SSOP packages.

___________________________Applications

Notebook Computers

Portable Data Terminals

Communicating Computers

Pen-Entry Systems

________________________________Features

o Dual PWM Buck Controllers (+3.3V and +5V)

o Two Precision Comparators or Level Translators

o 95% Efficiency

o 420µA Quiescent Current, 70µA in Standby

(linear regulators alive)

o 25µA Shutdown Current (+5V linear alive)

o 5.5V to 30V Input Range

o Small SSOP Package

o Fixed Output Voltages:

3.3V (standard)

3.45V (High-Speed Pentium™)

3.6V (PowerPC™)

_________________Ordering Information

Dual-Output Power-Supply

Controller for Notebook Computers

_______________________________________________________________________

Maxim Integrated Products

1

19-0160; Rev 2; 4/97

_____________________Pin Configuration

28

27

26

25

24

23

22

21

1

2

3

4

5

6

7

8

FB3

DH3

LX3

BST3

D1

ON3

SS3

CS3

TOP VIEW

DL3

V+

VL

FB5

Q1

Q2

VH

D2

20

19

18

17

9

10

11

12

PGND

DL5

BST5

LX5

SHDN

SYNC

REF

GND

SSOP

MAX786

16

15

13

14

DH5

CS5

SS5

ON5

Idle Mode is a trademark of Maxim Integrated Products. Pentium is a trademark of Intel Corp. PowerPC is a trademark of IBM Corp.

________Typical Application Diagram

MAX786

5.5V

TO

30V

SHUTDOWN

POWER

SECTION

POWER-GOOD

LOW-BATTERY WARNING

µP

MEMORY

PERIPHERALS

+3.3V

+5V

5V ON/OFF

3.3V ON/OFF

SYNC

SUSPEND POWER

28 SSOP

0°C to +70°C

MAX786RCAI

28 SSOP

0°C to +70°C

MAX786CAI

PIN-PACKAGE

TEMP. RANGE

PART

3.45V

3.3V

Ordering Information continued at end of data sheet.

EVALUATION

KIT

INFORMATION

INCLUDED

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.

For small orders, phone 1-800-835-8769.