Subthreshold-leakage suppressed switched capacitor circuit based on super cut-off CMOS (SCCMOS)

A subthreshold-leakage suppressed switched capacitor (SC) circuit based on a super cut-off CMOS (SCCMOS) scheme is introduced. This scheme realizes low-voltage SC circuits using low threshold voltage (V_TH) transistors which are superior in drivability and are compatible with digital circuits. The SC circuit cannot be operated under 0.5 V with high-V_TH devices, but, on the other hand, SC circuits with low-V_TH transistors suffer from charge loss, even in analog operations. A 0.5-V sigma-delta modulator with the proposed scheme is successfully manufactured and measured by using a 0.15-μm FD-SOI process with 0.1-V V_THN transistors.