A CMOS large-swing low-distortion three-stage class AB power amplifier

A CMOS power amplifier with a class AB rail-to-rail output stage is presented. By using a three-stage amplifier with double Miller compensation, the harmonic distortion of the output stage is suppressed by the internal feedback loops. This approach is thoroughly investigated, and it is shown that a three-stage amplifier has apparent advantages for DC gain, harmonic distortion, and power-supply rejection ratio (PSRR). A realized prototype for ISDN applications with a gain bandwidth (GBW) of 5 MHz and with -80-dB THD at 10 kHz for an output current of 20 mA in a load of 81 Omega is presented.<
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