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.