General Description
The MAX9810 microphone preamplifier is intended for use inside electret condenser microphone (ECM) cartridges. Current solutions use a FET as an impedance converter. FETs have limited gain, are susceptible to noise and require additional components external to the ECM cartridge for biasing and amplification. The MAX9810 replaces the FET with a high-gain, high-noise rejection, low-output-impedance amplifier. Designed to be integrated inside the ECM cartridge, the MAX9810 offers a flat frequency response, tightly controlled gain, increased sensitivity, and high-noise rejection greatly simplifying system design. Target applications include ECM cartridges in cell phones, PDAs, notebooks, and other portable audio devices.

Features
♦ Replaces FET in Electret Condenser Microphone
♦ 2.3V to 5.5V Single-Supply Operation
♦ Low-Impedance Output (<0.4Ω)
♦ High PSRR: 82dB
♦ Three High-Gain Options:
    MAX9810A: 24dB
    MAX9810B: 27dB
    MAX9810C: 30dB
♦ Internal Bias Voltage
♦ Low Supply Current (670µA)
♦ Rail-to-Rail® Output
♦ No Output Phase Reversal During Overload Conditions
♦ Available in a Tiny 4-Bump UCSP

Applications
    Electret Condenser Microphone Cartridges In:
        Cell Phones
        Notebooks
        PDAs
        Portable Audio