Design of a All-CMOS Second-Order Temperature Compensated Bandgap Reference

In this paper, a second-order temperature compensated bandgap voltage source based on 0.18 mu m standard COMS process with low temperature coefficient (TC) and high power supply rejection ratio (PSRR) was presented. The core structure of the circuit was the improvement of the traditional bandgap reference. The cascade structure was adopted to improve the PSRR and the line sensitivity, and the square of the proportional to absolute temperature current I-PTAT2 was utilized to compensate the first order circuit. This circuit constitutes of all-CMOS transistors in order to save the power consumption. The simulation results show that TC of the bandgap reference source in the -25 degrees C-125 degrees C temperature range, is 4.5 ppm/degrees C. At low frequency, the PSRR reaches -45.63 dB@100 Hz, and the power consumption is only 287.2 mu W.