A fW- and kHz-Class Feedforward Leakage Self-Suppression Logic Requiring No External Sleep Signal to Enter the Leakage Suppression Mode

In this letter, we present a novel logic family for nanowatt and subnanowatt always-on circuits. This logic family achieves the ultralow leakage of 5 fW per gate without requiring external sleep control signals to put the circuits in the leakage suppression mode while addressing the switching speed problem of such ultralow leakage logic families. It achieves the fan-out-of-4 delay of 10.2 μs, marking an improvement of 148× over the state-of-the-art. With the proposed logic family, we prototyped a unite impulse response ulter for physical signal sensing systems, in which sampled signals are often sparse (predominantly constant or slowly changing) and their frequency varies with time in a burst fashion. During the sparse period, the ulter consumes only 109 pW by autonomously suppressing leakage. It can still process signals whose bandwidth can be as high as half of the ulter's maximum operating frequency, 1.03 kHz. The proposed logic improves leakage-delay-product by 200× over the prior art.