Self-biased CMOS current reference based on the ZTC operation condition

A self-biased current reference based on the MOSFET Zero Temperature Coefficient (ZTC) condition is presented. It can be implemented in any CMOS process and it provides a simple alternative to design a reference current suitable for low TC biasing. This topology was designed in a 0.18 μm process to generate 5 μA under a supply voltage from 1.4V to 1.8 V, spending a silicon area around 0.010mm². From circuit simulations, the current reference is estimated to have a temperature coefficient (TC_eff ) of 15 ppm/°C from -40 to +85 °C and a fabrication sensitivity of σ/μ = 4.5%, including average process and local mismatch variability. The power supply sensitivity resulted around 1%V for this new reference.