A 0.9V 2.7µW small-area 100µs+ analog CMOS tunable-delay circuit utilizing Miller effect

We report a novel analog delay circuit based on Miller effect that features small die area and tunable delay in the order of 100 mus, without using any external component. The delay time can be tuned by varying the biasing current, capacitor sizes, transconductance of the gain-stage transistor and the corresponding output impedances. The turn-on threshold of the delay circuit can also be raised, as required in some applications, by utilizing the body effect of the input transistors. The circuit has a very low startup voltage (ap0.9 V) and consumes a very low power (ap2.7 muW) in a standard 1 mum pure CMOS process with V_tn ap 0.65 V and V_tp ap 0.8 V at 25degC. Circuit operations are elaborated and its function is verified by simulation and silicon measurement.