An Accurate All CMOS Bandgap Reference Voltage with Integrated Temperature Sensor for IoT Applications

Abstract

An accurate, robust CMOS voltage reference biased in subthreshold region with integrated temperature sensor circuit has been proposed in 180nm technology node using UMC RF process for IoT and low cost SoC applications. In UMC 180nm node the proposed reference voltage has an accuracy of 65 ppm/°C over 3σ variation in process and ±10% variation in supply, in the temperature range -40°C to 100°C. The proposed design achieves an accurate reference voltage and proportional to absolute temperature (PTAT) voltage at reduced process corner dependence, using a process invariant circuit in conjunction with a supply independent biasing circuit. The supply sensitivity of the output voltage is 4000 ppm/V at UMC 180nm. The proposed reference voltage in UMC 180nm technology consumes 12μW of power and is used for low power applications. The output voltage is 266mV at room temperature (27°C) in typical corner. The proposed reference voltage has been adjusted for process variation in MOSFETs and Resistors using a resistor trimming circuit. Noise analysis and supply sensitivity have been analyzed to prove the robustness of the proposed reference voltage design.