REFERENCE PRECHARGE TECHNIQUES FOR ANALOG-TO-DIGITAL CONVERTERS

Systems and methods to reduce the amount of reference current drawn by a SAR ADC by including an auxiliary or precharge reference source. The ADC can connect the bit trial capacitors of a main digital-to-analog converter (DAC) to an auxiliary or precharge reference source during the loading of the bit trials, and then the ADC can switch to a main reference buffer. After allowing enough time for both phases, the main DAC can proceed with the bit trials to resolve the remaining bits. The rest of the bit trials can be performed directly using the main reference buffer.