Patent ID: 7755421

Claim:
An apparatus comprising: an amplifier (e.g., 110 ) having a pair of differential input nodes (e.g., INP, INN) and a pair of differential output nodes (e.g., V ON , V OP ); first and second biasing circuits (e.g., R bias , R cm , i bias ) coupled to first and second input nodes of the pair of differential input nodes, respectively; and a first group of two or more selectable current sources (e.g., 116 ) coupled to the first input node, wherein the first group selectably adjusts DC voltage at the first input node to compensate for DC offset between the pair of differential output nodes; and a second group of one or more selectable current sources (e.g., 116 ), different from the first group, coupled to the second input node, wherein the second group selectably adjusts DC voltage at the second input node to compensate for the DC offset between the pair of differential output nodes.