A 1-V, 16.9 ppm/degrees C, 250 nA Switched-Capacitor CMOS Voltage Reference

Abstract

An ultra low-power, precise voltage reference using a switched-capacitor technique in 0.35-mu m CMOS is presented in this paper. The temperature dependence of the carrier mobility and channel length modulation effect can be effectively minimized by using 3.3 and 5V N-type transistors to operate in the saturation and subthreshold regions, respectively. In place of resistors, a precise reference voltage with flexible trimming capability is achieved by using capacitors. When the supply voltage is 1 V and the temperature is 80 degrees C, the supply current is 250 nA. The line sensitivity is 0.76%/V; the PSRR is -41 dB at 100 Hz and -17 dB at 10 MHz. Moreover, the occupied die area is 0.049 mm(2).