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

The author describes a 1-Ms/s. 16-bit analog-to-digital converter (ADC) that uses a subranging conversion technique. High accuracy at 1-MHz conversion rate is obtained with novel circuits developed for a track-and-hold (T/H), a residue amplifier, and a digital-to-analog converter (DAC). Design aspects of these key functional circuits are presented. A prototype ADC was fabricated on a PC board and tested. The results of curve fit tests show that, up to 100 kHz, effective bits are better than 16. However, signal bandwidth is commonly restricted in spectrum analysis; therefore, a dynamic range of over 96 dB can be obtained