Hmmm. The API 4300G is for use in industrial cabinets. Is that what you are after?
Is this a digital signal, ie: 0 mA = Logic 0, 100mA = Logic 1, or is it an analogue signal where you have to scale down a constantly variable signal from 0-100 mA down to 0 - 20 mA ?
The first you need convert 0-50mA to voltage, then design a constant current circuit using OPAMP, so the voltage can cotrol the output current , and you need set the ratio equal to 40%. I have ever used this method.But I don't know if there is a better way.
