A 16-bit low-voltage CMOS A/D converter

A/D converters used in telemetry, instrumentation, and measurements require high accuracy, excellent linearity, and negligible DC offset, but need not be fast. A simple and robust instrumentation A/D converter, fabricated in a low-voltage 4-μm CMOS technology, is described. The measured overall accuracy was 16 bits. Using a digital compensation for parasitic effects, both offset and nonlinearity were below 12 μV. With analog compensation, the offset was 60 μV and the nonlinearity below 15 μV. These results indicate that even higher accuracy can be achieved using higher voltage technology.