A sub-1-V, high precision, ultra low-power, process trimmable, resistorless voltage reference with low cost 90-nm standard CMOS technology

A low power voltage reference generator operating with a supply voltage ranging from 1.6 to 3.6 V has been implemented in a 90-nm standard CMOS technology. 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 3.6 V and at 125 C is 173 nA. It provides a 771 mV voltage reference. A temperature coefficient of 7.5 ppm/ C is achieved at best and 39.5 ppm/ 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. Several process parameters affect the performance of the proposed voltage reference circuit, so a process adjustment aimed at correcting errors in the reference voltage caused by these variations is dealt with. The total block area is 0.03 mm.