Telefonaktiebolaget LM Ericsson (publ)
Successive-approximation analog-to-digital converter

Abstract:

Disclosed is a SAR ADC (Ai) having an input for receiving an input voltage, a comparator, a first switch network configured to be controlled by the SAR state machine and connected to the input of the SAR ADC and to reference voltage nodes, and a first capacitor network. The first capacitor network has a first node connected to an input of the comparator, a second node, and a bridge capacitor (Cb) connected between the first node and the second node. Furthermore, the first capacitor network comprises a first set of capacitors having a first and a second terminal, wherein the first terminal of each capacitor in the first set is connected to the first node and the second terminal of each capacitor in the first set is connected to the switch network. Moreover, the first capacitor network comprises a second set of capacitors having a first and a second terminal, wherein the first terminal of each capacitor in the second set is connected to the second node and the second terminal of each capacitor in the first set is connected to the switch network. The SAR ADC further comprises a second capacitor network configured to control a gain of the SAR ADC.