DIGITAL-TO-ANALOG CONVERTER

摘要

A resistor string D/A converter for converting input data to multiple-bit data without increasing the number of resistors. The higher four bits of input data to be converted are supplied to a decoder (1) while the lower four bits are applied to a decoder (3) through an inverter (2). The decoder (1) decodes the higher four bits and turns on one of FETs (F0-F15) based on the decoded result. As a result, one of the voltages at the nodes between series resistors (r0-r15) is selected and applied to an operational amplifier (6). Similarly, the voltage corresponding to the lower four bits of the data is applied to an operational amplifier (7). The output from the operational amplifier (7) is divided by 16 through resistors (ra, rb), and the resulting voltage is combined with the voltage applied to the operational amplifier (6) to produce an analog voltage corresponding to the input data.