LMV1022

LMV1022/LMV1023 PDM Output Preamp for Electret Microphones LMV1022/LMV1023 OBSOLETE July 8, 2011 PDM Output Pre-Amplifier for Electret Microphones General Description The LMV1022 and LMV1023 integrate a pre-amplifier and ADC that can be mounted inside an electret condenser microphone (ECM). The digital output signal is a pulse density modulation (PDM) bitstream that alows the microphone to connect directly to the DSP or baseband processor. Part of National Semiconductor’s Powerwise™ family of products, the LMV1022/LMV1023 consume 900µW of power during operation, offering significant power savings over an analog microphone with an external ADC. The LMV1022 outputs its data on the rising clock edge. The LMV1023 outputs its data on the falling clock edge. Both devices can share the same clock and data lines to create a 4-wire stereo solution. The external clock frequency sets the audio pass band frequency. An 800kHz clock sets the pass band to 7kHz. A 2.4MHz clock sets the pass b...