Dynamic Threshold Pass-Transistor Logic for Improved Delay at Lower Power Supply Voltages - Solid-State Circuits, IEEE Journal of

We have investigated circuit options to surpass the 1-V power-supply limitation predicted by traditional scaling guidelines. By modulating the body bias, we can dynamically adjust the threshold voltage to have different onand off-state values. Several dynamic threshold voltage MOSFET (DTMOS) logic styles were analyzed for ultralow-power use—from 1.5 down to 0.5 V. Since ordinary pass-transistor logic degrades as the voltages are reduced, we investigated the effects that a dynamic threshold has on various styles of pass-transistor logic. Three different pass-transistor restoration schemes were simulated with the various DTMOS techniques. Results indicate that controlling the body bias can provide a substantial speed increase and that such techniques are useful over a large range of supply voltages. Process complexity and other tradeoffs associated with DTMOS logic variations are also discussed.