Design of a Second Order CMOS Sigma-Delta A/D Converter with a 150 MHz Clock Rate

A continuous time filter current switching sigma delta converter operating at a frequency of 150 MHz has been developed in 2 μm CMOS technology. The design of the main components of the converter is described including a very high speed comparator, an integrator and a one bit D/A converter. Measurements show a 10 bit dynamic range with 9 bit resolution at an oversampling rate of 128.