A 90-nm CMOS resistor-free compact trimmable voltage reference for ultra-low power low cost applications

A low power voltage reference generator operating with a supply voltage ranging from 1.6V to 3.6V has been implemented in a 90-nm standard CMOS process. The reference is based on MOSFETs that are biased in the weak inversion region to consume nanowatts of power and uses no resistors. The maximum supply current at 3.6V and at 125°C is 173nA. It provides an 771mV voltage reference. A temperature coefficient of 7.5ppm/°C is achieved at best and 39.5ppm/°C on average, in a range from −40 to 125°C, as the combined effect of a suppression of the temperature dependence of mobility and the compensation of the threshold voltage temperature variation. The total block area is 0.03mm2.