A CMOS bandgap reference with correction for device-to-device variation

A circuit technique for compensating the device-to-device variation in bandgap voltage references is presented. The circuit senses the variation of V/sub be/ of the transistor with process and pumps into the emitter a PTAT current in direction opposite to the variation to bring it back to the right value. It also exploits the temperature coeff. of MOS V/sub t/ to compensate for higher order temperature variations. Silicon results show a variation of 60 mV across different lots and less than 50 PPM across temperature (-40/spl deg/ to 130/spl deg/C). The prototype was built in a 0.18u CMOS digital process with low /spl beta/ PNP transistors.