Tunable Voltage Reference circuit in a standard 65nm CMOS technology

This paper presents tunable voltage reference (TVR) designed in a standard general purpose 65nm CMOS technology. Designed circuit is based on two-transistor (2T) voltage reference (VR) with digitally controlled operational amplifier (OPAMP). Developed TVR provides stable output voltage from 0.38 V to 1.1 V with non-linear tuning step under 0.5% of the output voltage (from 1.9 mV to 2.9 mV). The supply voltage in the range from 0.91 V to 1.5 V is used. The circuit offers parameter PSRR = -53.59 dB (at 1 kHz) and line regulation (LNR) of 0.35% in the worst case. The required area is 0.0185 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. The proposed TVR was used to precise frequency tuning of oscillator. Provided results are obtained from both simulations and measurement of the manufactured ASIC prototype.