A 1-V 2.5-ppm/°C second-order compensated bandgap reference

A new 1-V high precision second-order compensated bandgap voltage reference (BGR) is presented in this paper. It utilizes a conventional first-order current-mode BGR to balance the Complementary to Absolute Temperature (CTAT) voltage component of a forward biased BJT with a Proportional to Absolute Temperature (PTAT) voltage. The residual second-order error is corrected by the difference of two CTAT voltages with different non-linear terms through control of the collector currents of BJTs. All the circuits are designed using a standard 0.18μm CMOS process. The post-simulation results show that the maximum temperature coefficient (TC) of the proposed BGR at 1 V power supply is 2.5 ppm/°C over temperature range of -40°C to 125°C. The line regulation is 0.23 mV/V over supply range of 0.9 V-2 V. The low frequency power supply rejection of the circuit is -53 dB at 1 V power supply.