A study of SAR ADC and implementation of 10-bit asynchronous design

Successive Approximation Register (SAR) Analog-to-Digital Converters (ADCs) achieve low power consumption due to its simple architecture based on dominant digital content. SAR ADCs do not require an op-amp, so they are advantageous in CMOS technology scaling. The architecture is often the best choice for battery-powered or mobile applications which need medium resolution (8-12 bits), medium speed (10 - 100 MS/s) and require low-power consumption and small form factor. This work studies the architecture in depth, highlighting its main constraints and tradeoffs involving into SAR ADC design. The work researches asynchronous operation of SAR logic and investigates the latest trends for ADC’s analog components – comparator and DAC. 10-bit asynchronous SAR ADC is implemented in CMOS 0.18 µm. Design’s noise and power are presented as a breakdown among components.