Low temperature coefficient bandgap voltage reference generator
The maximum achievable performance of almost all mixed-signal and radio frequency systems is dependent on the accuracy of voltage references. The bandgap voltage of silicon at zero Kelvin, VGO is a physical constant with unit Volts. It is independent of process, supply voltage and temperature variations.
This work proposes a strategy for extracting VGO and expressing it at the output of a voltage reference circuit. The concept is implemented in UMC 65nm process and the simulation results indicate that the circuit design can achieve very low temperature coefficients (<1ppm/°C). The proposed concept is validated using measurements and the associated constraints are carefully investigated. The measured output voltage reference of the two tested units record a temperature coefficient of 3.4ppm/°C and 4.57ppm/°C across the industrial temperature range (-40°C to 85°C).