Patent ID: 7088274

Claim:
A digital-to-analog converter, comprising: (a) a difference amplifier with a non-inverting input, an inverting input, and an output; (b) a first resistor connected between said non-inverting input and a first reference potential; (c) a second resistor connected between said non-inverting input and a second reference potential; (d) a third resistor connected between said output and said inverting input; and (e) an R-2R resistor ladder network connected to said inverting input and with each 2R resistor having a switched connection to either said first or second reference potential, said switched connections set by an input digital word; (f) wherein said first resistor, said second resistor, and said third resistor all have resistance equal to R; (g) whereby a digital word used to set said switched connections is converted into an analog signal at said output.