Ultra low power A/D converters using an enhanced differential charge-transfer amplifier

An enhanced differential charge-transfer amplifier (DCTA) is first reported for use in ultra low power A/D Converters (ADCs) with particular application in highly integrated mobile or biomedical systems on a chip (SOCs). The DCTA features a new dynamic differential charge-transfer mechanism which greatly improves performance while actually reducing the number of transfer capacitors. An experimental ADC demonstrates the potential for more than an order of magnitude in power reduction over recent converters with comparable performance. The 0.6µm CMOS ADC consumes just 1.4µW/MS/s per comparator from a 2.1V supply and exceeds 30MS/s.