Patent ID: 7129878

Claim:
A digital to analog converter to convert a digital input signal into an analog output signal, comprising: a digital input having a plurality of digital input terminals for receiving said digital input signal; a switching circuitry comprising a plurality of switches, each switch comprising: an output terminal; a first input terminal electrically connected with a second voltage source in which said second voltage source provides a second reference DC voltage; a second input terminal electrically connected with a first voltage source in which said first voltage source provides a first reference DC voltage; and a control terminal electrically connected with said corresponding digital input terminal for selectively coupling one of said first input terminal and said second input terminal to said output terminal such that one of said first reference DC voltage and said second reference DC voltage outputted to said output terminal is determined by said digital input signal; and a resistance network with a resistance compensatory circuitry comprising: a set of series resistors; a plurality of CMOS compensatory circuitries electrically connected between two of said series resistors; and a set of shunt resistors each electrically connected to a plurality of common nodes of said series resistors and said CMOS compensatory circuitries respectively, wherein said CMOS compensatory circuitries are adapted to adjust the conversion from said digital input signal into said analog output signal.