CLASS-AB HIGH-SWING CMOS POWER-AMPLIFIER

For power amplifiers there is a need to combine small area and low quiescent power consumption with large peak currents and high output voltage swing. For a single 5-V supply, drain-coupled near class-A output stages are the best solution to this. These stages, however, suffer from large quiescent current variations and/or crossover distortion. A power amplifier for a loudspeaker and, in a smaller version, for the earpiece of a telephone are presented, where new solutions have been implemented to solve these problems. The amplifier has 1.2-mA quiescent current, 64-mA peak current, and >60 dB S/THD with 3.2-V output swing into a 25-OMEGA load.