A 250Mv, 0.063J/Ghash Bitcoin Mining Engine in 14nm CMOS Featuring Dual-Vcc Sha256 Datapath and 3-Phase Latch Based Clocking

Abstract

A 0.15mm2 Bitcoin mining engine is fabricated in 14nm CMOS with highest-reported energy-efficiency of 0.063J/GHash at 250mV, $25 ^{\circ}\mathrm {C}$. Fully-unrolled SHA256 datapath with Bitcoin-specific look-ahead/deferred digest optimizations and 3-cycle distributed scheduler provide 31/56% digest/scheduler delay reductions, resulting in 10% higher energy-efficiency with dual-Vcc operation. 3-phase latch-based clocking with stretchable non-overlapping clocks eliminates all min-delay paths, reducing total sequential power consumption by 50%. Robust mining operation over a wide supply range of 230–900mV is demonstrated, with 10–760MHash/s throughput measured at $100 ^{\circ}\mathrm {C}$.