A bit-stream digital-to-analog converter with 18-b resolution

摘要

A two-channel differential 18-b bit-stream digital-to-analog converter implemented in a 2.5- mu m BiCMOS process with 7.3-mm/sup 2/ chip area is described. The circuit contains two identical 1-b D-to-A conversion channels on one single chip. Each channel consists of a digital input part, a switched-capacitor D-to-A network, and two high-performance operational amplifiers. Total harmonic distortion plus noise is better than -102 dB. The dynamic range is more than 108 dB, giving a true 18-b resolution. Output operational-amplifier distortion is below 120 dB at full-scale signal. System design considerations, implementation, and measured results of the IC are discussed.