A bipolar monolithic analog subsystem for a 4½ digit A/D converter

A HIGHLY ACCURATE A/D convcrter has been required in data handling systems for a microprocessor and in digital multimeters. Responding to this recent demand, a CMOS monolithic structure has been widely employed in combination with the dual slope technique’ 7’. The CMOS process, however, places a limitation on the resolution of an A(D converter at 3% digits. In the dual slope technique, on the other hand, a feedback loop is constructed between the analog and the digital subsystems. This arrangement degrades the electrical isolation between the two systems.