MAX660

Switched Capacitor Voltage Converter

General Description

The MAX660 CMOS charge-pump voltage converter inverts

a positive voltage in the range of 1.5V to 5.5V to the corre-

sponding negative voltage. The MAX660 uses two low cost

capacitors to provide 100 mA of output current without the

cost, size, and EMI related to inductor based converters.

With an operating current of only 120 µA and operating effi-

ciency greater than 90% at most loads, the MAX660 pro-

vides ideal performance for battery powered systems. The

MAX660 may also be used as a positive voltage doubler.

The oscillator frequency can be lowered by adding an exter-

nal capacitor to the OSC pin. Also, the OSC pin may be used

to drive the MAX660 with an external clock. A frequency con-

trol (FC) pin selects the oscillator frequency of 10 kHz or 80

kHz.

Features

n Inverts or doubles input supply voltage

n Narrow SO-8 Package

n 6.5

Ω typical output resistance

n 88% typical conversion efficiency at 100 mA

n Selectable oscillator frequency: 10 kHz/80 kHz

Applications

n Laptop computers

n Cellular phones

n Medical instruments

n Operational amplifier power supplies

n Interface power supplies

n Handheld instruments

Typical Application Circuits

Connection Diagram

Ordering Information

Order Number

Top Mark

Package

Supplied as

MAX660M

Date Code

MAX660M

M08A

Rail (95 units/rail)

MAX660MX

Date Code

MAX660M

M08A

Tape and Reel (2500 units/rail)

Voltage Inverter

DS100898-1

Positive Voltage Doubler

DS100898-2

8-Lead SO

DS100898-5

Top View

November 1999

© 1999 National Semiconductor Corporation

DS100898

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