A 1 Ms/s 16-bit analog-to-digital converter

The author describes a 1-megasamples/s 16-bit analog-to-digital converter (ADC) that uses a subranging conversion technique. High accuracy at a 1-MHz conversion rate is obtained with novel circuits developed for a track-and-hold device, a residue amplifier, and a digital-to-analog converter. Design aspects of these key functional circuits are presented. A prototype ADC was fabricated on a printed-circuit board and tested. Curve-fit test results show that up to 100 kHz, the effective bits decrease to 14 bits due to wideband noise. However, signal bandwidth is commonly restricted in spectrum analysis, so a dynamic range of over 96 dB can be obtained