_______________General Description

The MAX863 dual-output DC-DC converter contains

two independent step-up controllers in a single com-

pact package. This monolithic bi-CMOS design draws

only 85µA when both controllers are on. The input

range extends down to 1.5V, permitting use in organiz-

ers, translators, and other low-power hand-held prod-

ucts. The MAX863 provides 90% efficiency at output

loads from 20mA to over 1A. This space-saving device

is supplied in a 16-pin QSOP package that fits in the

same area as an 8-pin SOIC.

The device uses a current-limited, pulse-frequency-

modulated (PFM) control architecture that reduces start-

up surge currents and maintains low quiescent currents

for excellent low-current efficiency. Each controller

drives a low-cost, external, N-channel MOSFET switch,

whose size can be optimized for any output current or

voltage.

In larger systems, two MAX863s can be used to gener-

ate 5V, 3.3V, 12V, and 28V from just two or three bat-

tery cells. An evaluation kit (MAX863EVKIT) is available

to speed designs. For a single-output controller, refer to

the MAX608 and MAX1771 data sheets.

________________________Applications

2- and 3-Cell Portable Equipment

Organizers

Translators

Hand-Held Instruments

Palmtop Computers

Personal Digital Assistants (PDAs)

Dual Supply (Logic and LCD)

____________________________Features

o Smallest Dual Step-Up Converter: 16-Pin QSOP

o 90% Efficiency

o 1.5V Start-Up Voltage

o 85µA Max Total Quiescent Supply Current

o 1µA Shutdown Mode

o Independent Shutdown Inputs

o Drives Surface-Mount, Dual N-Channel MOSFETs

o Low-Battery Input/Output Comparator

o Step-Up/Down Configurable

Dual, High-Efficiency, PFM, Step-Up

DC-DC Controller

________________________________________________________________

Maxim Integrated Products

1

MAX863

EXT2

CS2

OUT2

OUT1

N

N

ON/OFF

FB2

SHDN1

EXT1

CS1

LBO

LOW-BATTERY

DETECTOR OUTPUT

LBI

PGND

BOOT

GND

FB1

SHDN2

REF

__________________Pin Configuration

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

SENSE1

REF

SHDN2

LBI

LBO

FB2

SHDN1

CS2

EXT2

TOP VIEW

MAX863

QSOP

FB1

EXT1

BOOT

CS1

GND

PGND

__________Typical Operating Circuit

19-1218; Rev 1; 6/97

PART

MAX863C/D

MAX863EEE

-40°C to +85°C

0°C to +70°C

TEMP. RANGE

PIN-PACKAGE

Dice*

16 QSOP

EVALUATION

KIT MANUAL

AVAILABLE

______________Ordering Information

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

*