Voltage reference based on CMOS threshold voltage

Abstract

A novel low temperature coefficient voltage referece without resistors is presented in this brief, which is compatible with standard TSMC 0.18 µm CMOS technology. Threshold voltage (Vth) and proportional to absolute temperature voltage (VPTAT) form the basic linear temperature components. By weighting the sum of the two through asymmetric differential operational amplifier, the nonlinearity in the voltage reference is cancled and the precision of the output voltage is improved. The Vth is achieved by resistorless circuit and the VPTAT is achieved by asymmetric differential operational amplifier. The experimental results show that in the temperature range of -55 ℃ to 125 ℃, the voltage reference is 1.23 V with a temperature coefficient of 4.5 ppm/℃, and the power supply rejection ratio is lower than -93 dB while without filtering capacitor.

Keywords

• voltage reference
• threshold voltage
• temperature coefficient
• psrr