1 Features

1• Inverts or Doubles Input Supply Voltage

• Narrow SO-8 Package

• 6.5-Ω Typical Output Resistance

• 88% Typical Conversion Efficiency at 100 mA

• Selectable Oscillator Frequency: 10 kHz/80 kHz

2 Applications

• Laptop Computers

• Cellular Phones

• Medical Instruments

• Operational Amplifier Power Supplies

• Interface Power Supplies

• Handheld Instruments

3 Description

The MAX660 CMOS charge-pump voltage converter

is a versatile unregulated switched-capacitor inverter

or doubler. Operating from a wide 1.5-V to 5.5-V

supply voltage, the MAX660 uses two low-cost

capacitors to provide 100 mA of output current

without the cost, size and EMI related to inductorbased

converters. With an operating current of only

120 μA and operating efficiency greater than 90% at

most loads, the MAX660 provides ideal performance

for battery-powered systems. MAX660 devices can

be operated directly in parallel to lower output

impedance, thus providing more current at a given

voltage.

The FC (frequency control) pin selects between a

nominal 10-kHz or 80-kHz oscillator frequency. The

oscillator frequency can be lowered by adding an

external capacitor to the OSC pin. Also, the OSC pin

may be used to drive the MAX660 with an external

clock up to 150 kHz. Through these methods, output

ripple frequency and harmonics may be controlled.

Additionally, the MAX660 may be configured to divide

a positive input voltage precisely in half. In this mode,

input voltages as high as 11 V may be used.