Patent ID: 6710731
Filing Date: 2004-03-23
Classification: H03M

Abstract:
A digital-to-analog converter comprising:a first stage comprising an n-bit resistor string converter for receiving an input digital signal; a second stage comprising an m-bit resistor string converter for generating an output analog signal, wherein a unity-gain operational amplifier couples the first and second stages, the converted signal having effectively guaranteed monotonicity; the first stage comprises a 1-bit resistor string-converter having a first end at a reference high voltage and a second end at a reference low voltage, and the second stage comprises a multi-bit resistor string converter; and a buffer amplifier input couples between a plurality of resistors of the 1-bit resistor string converter, and the output signal is coupled to one end of the multi-bit resistor string; wherein the buffer amplifier offset-voltage is variable for compensating a resistor mismatch.