General Description
The MAX768 low-noise, dual-output, regulated charge pump provides a negative output for biasing GaAsFET power amplifiers, and a positive output for powering voltage-controlled oscillators (VCOs) in wireless handsets. The outputs can also be used to power LCDs. Output ripple is less than 2mVp-p. The MAX768 is intended for use in low-voltage systems where a simple charge-pump inverter is inadequate, or where the VCO needs more range to improve its signal-to-noise ratio. The input range is 2.5V to 5.5V, enabling direct power from 1Li+ and 3-cell NiMH/NiCd batteries.

Features
♦ Dual Positive/Negative Regulated Outputs: ±5VOUT from 3VIN
♦ Output-Ready Indicator to Protect GaAsFET PAs
♦ 2.5V to 5.5V Input Voltage Range
♦ Low-Noise Output Ripple: < 2mVp-p
♦ Synchronizable Switching Frequency
♦ Uses Only Small, Low-Cost Capacitors
♦ 0.1µA Independent Shutdown Controls
♦ Adjustable Output Voltages
♦ Small 16-Pin QSOP Package

Applications
    GaAsFET Power Amp Bias
    Voltage-Controlled Oscillator (VCO) Supply
    Tuner Diode Power Supply
    Positive and Negative LCD Supply
    Cellular Phone
    PCS and Cordless Phone
    Wireless Handsets
    Wireless Handheld Computers
    Wireless PCMCIA Cards
    Modems