Abstract: A novel low-offset dynamic comparator for high-speed low-voltage analog-to-digital converters (ADCs) has been proposed. In the proposed comparator, a CMOS switch takes the place of the dynamic current sources in the differential comparator, which allows the differential input transistors still to operate in the saturation region at the comparing time. This gives the proposed comparator a low offset as the differential comparator while tolerating a sub-1-V supply voltage. Additionally, it also features a larger input swing, less sensitivity to common mode voltage, and a simple relationship between the input and reference voltage. This proposed comparator with two traditional comparators has been realized by SMIC 0.13 μm CMOS technology. The contrast experimental results verify these advantages over conventional comparators. It has been used in a 12-bit 100-MS/s pipeline ADC.

Key words: comparator