A volume and tone control IC for Hi-Fi audio

A monolithic IC which contains dual-channel volume control circuits, tone control circuits, and function switches is discussed. The IC has excellent characteristics, such as total harmonic distortion of less than 0.002 percent (at 1 kHz, 300 mV rms input signal) and a signal-to-noise ratio of more than 100 dB (at 300 mV rms input signal, A weighting). SIPOS-gate MOSFET's and polysilicon ion implanted resistors are employed, yielding good signal level accuracy and low distortion.