Disruptive ultra-low-leakage design techniques for ultra-low-power mixed-signal microsystems

In this paper, we describe applications of a disruptive ultra-low-leakage design technique for drastically reducing the off current in CMOS mixed analog-digital microsystems without compromising the functional performance. The technique is based on a pair of source-connected n- and p-MOS transistors, automatically biasing the stand-by gate-to-source voltage of the nMOSFET at a negative voltage and that of the pMOSFET at a positive level, thereby pushing the off current towards its physical limits. Playing with gate and drain connections, we have created a family of ULP basic blocks: a 2-terminal diode, a 3-terminal transistor and a voltage follower. Using these blocks, we have developed a 7-transistor SRAM cell and an MTCMOS latch with record low stand-by leakage but still high speed performance, highly-efficient power-management units for RF and PV energy harvesting and a microwatt interface for implanted capacitive sensors.