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For small orders, phone 408-737-7600 ext. 3468.

General Description

The MAX868 inverting charge pump provides a low-cost

and compact means of generating a regulated negative

between 1.8V and 5.5V. It uses a pulse-frequency-

modulation (PFM) control scheme to generate the regulat-

ed negative output voltage. PFM operation is obtained

by gating the internal 450kHz oscillator on and off as

needed to maintain output voltage regulation. This

unique on-demand switching scheme gives the MAX868

excellent light-load efficiency without degrading its full-

load operation (up to 30mA), permitting smaller capaci-

tors to take advantage of the oscillator’s high switching

frequency.

The MAX868 requires no inductors; only four capacitors

are required to build a complete DC-DC converter.

Output voltage regulation is achieved by adding just two

resistors. The MAX868 comes in a 10-pin µMAX pack-

age, which is only 1.11mm high and occupies just half

the board area of a standard 8-pin SO.

________________________Applications

Small LCD Panels

Cell Phones

Cordless Phones

Camcorders

Handy-Terminals, PDAs

Medical Instruments

Battery-Operated Equipment

____________________________Features

o Regulated Negative Output Voltage

o Ultra-Small, 10-Pin µMAX Package

o On-Demand Switching at up to 450kHz

o 30µA Quiescent Supply Current

o Requires Only Four Small External Capacitors

o 1.8V to 5.5V Input Voltage Range

o 0.1µA Logic-Controlled Shutdown

o Up to 30mA Output Current

Regulated, Adjustable -2x

Inverting Charge Pump

________________________________________________________________

Maxim Integrated Products

1

1

2

3

4

5

10

9

8

7

6

FB

SHDN

C2+

IN

PGND

C1-

OUT

GND

MAX868

µMAX

TOP VIEW

C2-

C1+

Configuration

MAX868

C1+

IN

PGND

SHDN

GND

FB

OUT

0.1

µF

1

µF

2.2

µF

0.1

µF

C1-

C2+

C2-

Typical Operating Circuit

19-1290; Rev 1; 2/98

PART

MAX868C/D

MAX868EUB

-40°C to +85°C

0°C to +70°C

TEMP. RANGE

PIN-PACKAGE

Dice*

10 µMAX

Ordering Information

*