Design and Analysis of PVT Invariant Current Reference in 65-nm CMOS

In this paper, a CMOS current reference circuit has been proposed for achieving a PVT compensated current. The design is based on a modified version of the beta multiplier circuit with an on-chip resistor implemented using transistor in the deep triode region. Compensation of process corner variation is done by using a process tracking circuit (PTC). Temperature variation compensation is achieved by cancelling the PTAT variation of the beta multiplier circuit with the CTAT gate voltage of the on-chip transistor based resistor. The design has been implemented in 65 nm CMOS technology and simulated in Cadence specter. The current reference achieves a process variation of 1.4% and it has a temperature coefficient of 276.8 ppm/degrees C over a temperature range of 0 degrees C to 100 degrees C. The reference current generated in this design is 8.8 mu A with a supply voltage of 1.2 V, giving a net power consumption 126.56 mu W.