Design of a tunable temperature coefficient voltage reference with low-dropout voltage regulator in 180-nm CMOS technology

This paper presents a voltage reference having a tunable temperature coefficient and a low-dropout voltage supply. The circuit has been designed using the Cadence Virtuoso software package and afterwards processed and measured. It is possible to arbitrarily set the first-order temperature coefficient to achieve compensation of the oscillator resultant temperature coefficient. The low-dropout voltage regulator provides a nominal output voltage of 1.2 V with a maximum output current of 2 mu A. It requires a 600-mV voltage reference and 50-nA current reference for proper operation. As a result of the analysis, it is concluded that the voltage reference has a default temperature coefficient of -37.7 ppm/degrees C. The voltage reference is buffered and additionally compensated using the tunable temperature coefficient resistor with the step of 20 ppm/degrees C controlled by a 4-bit input vector and temperature coefficient range of +/- 150 ppm/degrees C.