A 2 V, 10 b, 20 Msample/s, mixed-mode subranging CMOS A/D converter

We have developed a 2 V, 10 b, 20 MS/s, mixed-mode (voltage-mode and current-mode) subranging CMOS A/D Converter (ADC) suitable for video-signal processing systems. Its 2 V supply voltage and 20 mW power consumption are lower than those of any other video-rate ADC reported to date. This ADC employs voltage-mode circuitry for coarse 5 b A/D conversion and current-mode circuitry for fine 6 b A/D conversion. In addition to this mixed-mode subranging architecture, a newly developed differential comparator and a new current-tree A/D conversion architecture also contribute to the achievement of high speed at low supply voltage.