Design of a TID-tolerant low-level offset operational amplifier

An auto-zero operational amplifier dedicated to space applications is proposed. Its operation principle is based on a continuous-time auto-zeroed amplifier topology to provide a low-level offset. The circuit was implemented in a standard 130 nm CMOS technology. Simulations show that the residual offset is reduced to a few microvolts. The gain bandwidth product is estimated at 10 MHz, and the slew-rate at 7 V/μs for a load capacitor of 10 pF. The current supply is about 300 μA.