Abstract: This article shows an example of implementing a 4-20mA or 0-20mA current-loop output using a voltage output digital-to-analog converter (DAC) and a V to I converter. Maxim > App Notes > A/D and D/A CONVERSION/SAMPLING CIRCUITS AMPLIFIER AND COMPARATOR CIRCUITS SWITCHES AND MULTIPLEXERS Keywords: 4-20mA, 0-20mA, current loop, current loop transmission, DAC, V/I, V to I, converter, digital to May 31, 2002 analog converter APPLICATION NOTE 1085 Selectable-Range Current Loop Abstract: This article shows an example of implementing a 4-20mA or 0-20mA current-loop output using a voltage output digital-to-analog converter (DAC) and a V to I converter. Current-loop signals, as opposed to voltage signals, are commonly used in industrial systems because they are much less subject to noise and relatively indifferent to line length (because the current is unaffected by line resistance). The circuit of Figure 1 allows digital selection between the two standa……