The workhorses in the mixed-signal world, or the link between the digital processing world and the analog real world, are the analog-to-digital converter (ADC) and digital-to-analog converter (DAC) ICs, which generally are grouped as the data converters. In general, a designer has to select the type of converter based on many specifications and design constraints such as cost, packaging, and power consumption. To specify intelligently the ADC portion of the system, one must first understand the fundamental concepts of sampling and quantization and their effects on the signal. The most common ADC architectures in monolithic form are successive approximation, flash, integrating, pipeline, half-flash (or subranging), two-step, interpolative and folding, and sigma-delta. The successive approximation register (SAR) ADC architecture is a popular and cost-effective form of converter for sampling frequencies up to a few megasamples per second (MSPS).