We start by establishing our overall system-performance requirements. Each component in the system will have an associated error; the goal is to keep the total error below a certain limit. Often the ADC is the key component in the signal path, so we must be careful to select a suitable device. For the ADC, let's assume that the conversion-rate, interface, power-supply, power-dissipation, input-range, and channel-count requirements are acceptable before we begin our evaluation of the overall system performance. Accuracy of the ADC is dependent on several key specs, which include integral nonlinearity error (INL), offset and gain errors, and the accuracy of the voltage reference, temperature effects, and AC performance. It is usually wise to begin the ADC analysis by reviewing the DC performance, because ADCs use a plethora of non-standardized test conditions for the AC performance, making it easier to compare two ICs based on DC specifications. The DC performance will in general be better than the AC performance.