Abstract: A high precision bandgap voltage reference with chopped modulator is presented in this paper.The chopper modulator is used to compensate the Random error caused by the offset of the opamp and improve the accuracy of the bandgap refrence.In the 0.25 μm BiCMOS models,Resultsfrom simulation showed that,Considering ±2% mismatch of input pairs respectively,the peak-to-peak value of the output ripple is 0.38 mV.The relative accuracy is increased by 113 times compared with the traditional bandgap voltage reference.With supply voltage range from 2.5 V to 6.0 V,the variation of the output is approximately 0.085 mV.In the temperature range from -40℃ to 125℃,the bandgap voltage reference had a temperature coefficient of 19 ppm/℃.