Generation of Two Least Significant Bits in a Resistive Digital-To-Analog Converter
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
This article describes how a 10-bit digital-to-analog converter (DAC) may be designed from a 8-bit digital-to-analog resistive converter without accuracy degradation and with a limited additional area on the chip into which the converter is integrated. Fig. 1 shows schematically an 8-bit resistive DAC. It comprises 256 elementary resistors Ro in series with resistors Rx and Ry. The output voltage follower provides the analog output voltage, the value of which depends upon the bits of the word to be converted. The power supplies of the follower limit the input range of the follower. Resistors Rx and Ry allow the resistor bridge to fit the follower input range.