Datasheet

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 6.5Ω 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
MAX660 Switched Capacitor Voltage Converter
© 1999 National Semiconductor Corporation DS100898 www.national.com