Abstract: Based on a physical understanding of nonlinearity and mismatch,a novel offset-cancellation technique for low voltage CMOS differential amplifiers is proposed.The technique transfers the offset voltage from the output to other parts of the differential amplifier and can greatly reduce the input-referred offset voltage without extra power consumption.A 1.8V CMOS differential amplifier is implemented in 0.18μm CMOS process using the proposed technique.The simulation results show that the technique could reduce the input-referred offset voltage of the amplifier by 40% with a 20% load transistor mismatch and a 10% input differential transistor mismatch.Moreover,the proposed technique consumes the least power and achieves the highest integration among various offset-cancellation techniques.

Key words: CMOS, input-referred offset voltage, offset voltage calibration, low offset voltage