Temperature compensated CMOS voltage reference

A fully integrated digitally calibrated voltage reference is presented. This reference is mostly digital, making use of a simple low-pass RC filter as the only analog component. The proposed circuit can be used for single ended as well as differential applications. Temperature tests revealed a temperature coefficient of less than 200 ppm//spl deg/C without calibration, and less than 20 ppm//spl deg/C using calibration. The voltage reference circuit was successfully verified using a prototype IC in a 0.35 /spl mu/m CMOS process.