Patent ID: 7884747

Claim:
A digital to analog converter (DAC), comprising: a pair of operational amplifiers, each having a first input to couple to a respective source voltage; and a plurality of switch-controlled cells, each cell comprising: a resistor, a first force/sense pair of switches coupled to each other in series and rendered conductive in response to a first state of a control signal, an intermediate node of the first pair of switches coupled to the resistor, a force switch of the first pair coupled to an output of the first amplifier, and a sense switch of the first pair coupled to a second input of the first operational amplifier, and a second force/sense pair of switches coupled to each other in series and rendered conductive in response to a second state of a control signal, an intermediate node of the second pair of switches coupled to the intermediate node of the first pair of switches, a force switch of the second pair coupled to an output of the second amplifier, and a sense switch of the second pair coupled to a second input of the second operational amplifier.