An 8-bit 3MS/s CMOS two-step flash converter for low voltage mixed signal CMOS integration

Many large, mainly digital system ICs require on-chip A/D conversion for their input interface, and the task of incorporating this function into a hostile environment is not trivial. As power supplies for these digital systems are reduced, the analogue functions must follow suit. In this paper we describe a two-step flash converter capable of operating at 3MS/s with a supply voltage of just 3V. The circuit uses a novel offset cancelling comparator particularly suited to these applications. The circuit has been fabricated in 0.8 μ CMOS, and has been incorporated into large system ICs