A low-current DC-coupled compander

A compander that uses DC-coupling, a fixed 1.5-V reference, a class-B variable-gain stage, and a class-AB amplifier output stage capable of swinging within a saturation voltage of supply and ground is described. Implementation of the design on a standard 20-V bipolar process yields channel separation of -64 dB for the compressor and -80 dB for the expander, a power supply rejection of -46 dB, and a drain current of 1.2 mA. The application requires six 1 mu F surface-mount capacitors and takes advantage of thin-film resistor technology for critical matching requirements.<>