A Dual Low Voltage Chopper Offset-Stabilized Operational Amplifier

The paper presents a dual low voltage chopper offset-stabilized operational amplifier with symmetrical RC notch filters, having a 1.6-5.5 V supply range, and being fabricated in a 0.25 µm CMOS process. The chopping frequency is 100 kHz. A new constant-gm technique is implemented within the input stage of main amp, improving most electrical performances. The amplifier has a typical offset voltage of 1 µV, a minimum PSRR of 128 dB, a minimum CMRR of 120 dB, a noise PSD of 42 nV/√Hz, 1.5 MHz unity gain bandwidth, and THD + noise of 0.001 % at 1 kHz, while consuming 70 µA per channel.