We have some 15V digital outputs that are pretty fast. They are connected to other modules by means of a cable and the worry is that somehow a cable can be misplaced, so that we could feed 30VDC into the15V output.
Right now we use a resistor, but due to the low output impedance requirements, the power dissipation when shorting to 30VDC is very large (4W).
So, do any of you guys know of either an IC or a simple circuit solution to feed through the signal with low impedance and also protect the output from shorts to ground and 30VDC?
(I thought about something crazy like a resettable fuse, or using protection diodes on the output to the supply rails and a precision clamp on the rails to quinch the rising rail voltage in case of an errer)