General Description

The MAX864 CMOS, charge-pump, DC-DC voltage converter produces a positive and a negative output from a single positive input, and requires only four capacitors. The charge pump first doubles the input voltage, then inverts the doubled voltage. The input voltage ranges from +1.75V to +6.0V.

The internal oscillator can be pin-programmed from 7kHz to 185kHz, allowing the quiescent current, capacitor size, and switching frequency to be optimized. The 55Ω output impedance permits useful output currents up to 20mA. The MAX864 also has a 1µA logic-controlled shutdown.

The MAX864 comes in a 16-pin QSOP package that uses the same board area as a standard 8-pin SOIC. For more space-sensitive applications, the MAX865 is available in an 8-pin µMAX package, which uses half the board area of the MAX864.

Features

♦ Requires Only Four Capacitors

♦ Dual Outputs (Positive and Negative)

♦ Low Input Voltages: +1.75V to +6.0V

♦ 1µA Logic-Controlled Shutdown

♦ Selectable Frequencies Allow Optimization

   of Capacitor Size and Supply Current

Applications

   Low-Voltage GaAsFET Bias in Wireless Handsets

   VCO and GaAsFET Supply

   Split Supply from 2 to 4 Ni Cells or 1 Li+ Cell

   Low-Cost Split Supply for Low-Voltage Data-Acquisition Systems

   Split Supply for Analog Circuitry

   LCD Panels