A process and temperature invariant on-chip resistor and its application

This paper presents a novel bias circuit for achieving process and temperature invariant resistor using a MOSFET operating in triode region. The proposed circuit comprises of an enhanced process tracking circuit and complementary to absolute temperature (CTAT) voltage generators. The proposed circuit has been designed and optimized in 180nm mixed-mode CMOS technology. Exhaustive Montecarlo simulations show that the ON resistance of the MOSFET (R_ON) varies only by ± 7.6% with process and ± 1.2% with temperature ranging from 0°C to 100°C. The proposed bias circuit reduces variation in R_ON by a factor of 3.4 as compared to a fixed bias MOSFET. The proposed circuit consumes 130μW power.