Analysis of Operational Amplifier Requirements for Extended-Range Second-Order Incremental ADCs

This paper presents the sensitivity analysis of an extended-range, second-order Incremental ADC (IADC) to the non-idealities of the operational amplifiers (op-amps) used. Different configurations of the extended-range IADCs are compared in terms of required ENOB and op-amp specifications. In all the configurations, a flash ADC with varying resolution is used as extended-range ADC. The ADC clock frequency is considered in all cases equal to 80 MHz. From the analysis it turns out that, in order to achieve a given ENOB, the extended-range IADC requires a significantly lower number of clock cycles than a conventional IADC, but the requirements of the op-amps are much more stringent.