Digital-to-analog converter

摘要

The present invention provides a high-accuracy and multi-bit D/A converter which can be produced using a CMOS process. A resistor string is formed of a plurality of resistors connected in series. A switch matrix has switch strings each formed of switches each having one end thereof connected to a corresponding one of junctions of the resistors and having respective other ends commonly connected to one of common junctions. A decoder turns on and off the switches of the switch strings according to more significant bits of data for conversion. A less significant bits-conversion circuit generates a voltage corresponding to less significant bits of the data for conversion and outputs the voltage. An operational amplifier carries out addition or subtraction of a voltage at each of the common junctions and an output from the less significant bits-conversion circuit.