A low-voltage, low-power, CMOS programmable Analog Front-End ICfor 3 V digital cellular phone applications is presented. The chip canbe configured either as a classical A/μ law PCM codec or as a 13-bitslinear codec. Its high performance speech interface results in amicrophone preamplifier with about 0.5 mV offset and 1.3 μVrms input-referred noise for the transmit channel, while it iscapable of driving loads up to 27 Ω or 50 nF with 4Vpp, output voltages and -80 dB of THD in the receive path. Atone generator that can also be used for ringing or DTMF signalingpurpose, and a dedicated pulse-width modulated output for a buzzercomplete the chip functions. All programmable functions can be accessedvia a standard four wire control interface. These performances have beenachieved from a 3 V supply with operative and stand-by powerconsumptions of 21 mW and 1.5 μW, respectively. Chip area is 22.7 mm2 in a 0.8 μ CMOS process
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