Characterization of On-chip Interconnections and Capacitive Coupling Effect on CMOS Operational Amplifier

The operational amplifier is one of the most important circuits to compose ADCs, DACs and active filters. Now, there are many papers which deal with noise characters of op amps. Most of them are focused on the input signal noises which flow into circuits without account about noise source. Capacitive coupling is one of the most frequent sources of signal noise. The capacitive coupling is inevitable because of high integration. This paper investigates mechanism of input noises flowing into the op amp and effects of capacitive coupling on the op amp as on-chip interconnection modeling and analytical model of the DC output offset voltage of the OPamp are proposed. Furthermore, the models are verified by experimental measurement.