A CMOS band-gap voltage reference with low offset

A CMOS band-gap voltage reference with the characteristics of low offset and low supply voltage is presented in this paper. In order to reduce the effect of offset of operational amplifier, two feedback loops are introduced, so as to the factor of ¿V _BE is maximized meanwhile the factor of offset could be minimized. The area of layout is 1.5×1.3 mm ² with a 0.5 um CMOS process. Post-simulation results show that the temperature coefficients of output is 9 ppm/°C over the range from -50°C to 85°C, and PSRR of the circuit at low frequency is -90 dB.