Abstract: A pseudo-random signal generator circuit for auto-zero operational amplifiers is proposed. The circuit combines linear feedback shift register and multi-stage counter to realize the function of random change of output signal frequency within a certain range. The multi-stage counter is set by using the 7-bit pseudo-random code generated by the 7-stage linear feedback shift register, and the counter starts to count in the set state. When the counter is full, the output signal transitions once. At the same time, the linear feedback shift register generates a new pseudo-random code to reset the counter circuit, and the counter counts again. Finally, an output signal whose frequency varies randomly within a certain range is generated. The output signal is used as the switching timing signal of the auto-zero amplifier offset calibration circuit, so that the switching action of the auto-zero op amp's offset voltage calibration circuit (switched capacitor structure) has randomization characteristics, and the generated switching glitch is similar to random noise, which improves the Calibration effect of auto-zero amplifier offset voltage. The pseudo-random signal generator circuit is realized by 0.5 μm CMOS process. The simulation results show that the frequency of the output signal generated by the signal generator circuit varies randomly in the range of 2 kHz to 4 kHz. Using it for offset voltage calibration of auto-zero op amps, the harmonics in the auto-zero op amp output signal are significantly reduced.