Patent ID: 8643529

Claim:
A method for operating a SAR assisted pipelined ADC, wherein the SAR assisted pipelined ADC comprises a current stage circuit and a next stage circuit, each of the stage circuits comprises a SAR ADC and an MDAC, and each MDAC comprises an operational amplifier, the method comprising: enabling the SAR ADC in the current stage circuit for converting an input analog voltage into a digital code during a first time interval; resetting the operational amplifier of the MDAC of the current stage circuit during the first time interval; maintaining the SAR ADC of the current stage circuit in an enabled state for outputting during a second time interval; enabling the MDAC of the current stage circuit during the second time interval, wherein an output terminal of the MDAC of the current stage circuit is isolated from an input terminal of the next stage circuit; enabling the SAR ADC of the current stage circuit for sampling during a third time interval; and connecting the output terminal of the MDAC of the current stage circuit to the input terminal of the next stage circuit during the third time interval, wherein the first time interval, the second time interval, and the third time interval are continuous and do not overlap each other.