A Low-power, Small-area and Programmable Bandgap Reference

In this paper, we present a low-power, small-area and programmable bandgap reference, based on the reverse bandgap reference concept. It is implemented in a 65nm digital CMOS process with 1.2V power supply. It employs two switched capacitor amplifiers to weight temperature dependent voltages with opposite polarity. Programmability is achieved by adjusting a closed-loop gain of these two amplifiers. The implemented BGR generates three reference voltages, such as 0.591V (V-REF1), 0.872V (V-REF2) and 1.189V (V-REF3). In simulation, with +/-10% supply voltage variation, the temperature coefficient (TC) of V-REF1, V-REF2 and V-REF3 is less than 43ppm/degrees C, 28ppm/degrees C and 33ppm/degrees C, respectivley, in the temperature range from -40 degrees C to 100 degrees C. The average power consumption is less than 40 mu W for V-REF1, 60 mu W for V-REF2 and 110 mu W for V-REF3. The layout area (excluding bonding pads) is 200 mu m by 190 mu m.