Miro Oljaca and Bonnie Baker
Texas Instruments

This article is Part 2 of a three-part series that investigates the design and performance of a voltage-reference system for a successive-approximation register (SAR) analog-todigital converter (ADC). When a design uses an ADC in this system, it is critical to understand the voltage-reference path to the converter. Part 1 examined the fundamental operation of an ADC independent of the voltage reference, and then analyzed the performance characteristics that have an impact on the accuracy and repeatability of the system. Part 2 looks at the key characteristics of the voltage-reference block and the reference's possible impact on the ADC's performance.