A single chip BiMOS telephone set

Abstract

A single-chip telephone set in BCD (bipolar, CMOS and DMOS) technology is described. It integrates all of the functions usually found in a telephone set: reception, transmission, power supply generation, ringer, loudspeaker, and bistandard dialing (loop disconnect and dual-tone multifrequency). A 30-V bipolar technology is used to treat analog signals, 12-V CMOS for control and generation of the pulses/tones for dialing, and 60-V DMOS for ringer high-voltage driver. The block diagrams of the analog and digital parts are shown. The single chip has proved that a telephone set combining mixed features like high voltage, high power, low noise, and intelligibility can be integrated using a mixed BCD bipolar CMOS and process. The availability of differing components on the same substrate makes possible the solution of problems in the analog domain without compromise.<>