Seven subthreshold flip-flop cells

For ultra-low-power applications, operating the transistors in their subthreshold region is an effective way of reducing the power dissipation of a circuit. This paper presents a comparative study of the performance of seven D-flip-flop cells operating in the subthreshold region, based on simulations in a 90 nm CMOS technology. Simulations have been performed with a supply voltage ranging from 150mV to 350mV. The best PDP and EDP numbers at 175mV is 13 aJ and 10 yJs, respectively.