Our new product uses a SN65LVDS047 transmitter and SN65LVDS3486 receiver to communicate between 2 boards over a a short (12") distance using a standard unshielded ethernet cable. Our production tech accidentally connected the transmitter to the transmitter on the second board. During debug, he found that both transmitter IC's were damaged and had to be replaced. Correctly connecting the cables after set everything right.
I'm wondering what caused the IC's to fail? Driving one transmitter into the other, I wouldn't think would cause both IC's to fail at all (looking at the output stage driver in the datasheet) since it is low voltage and there are 50 ohm series resistors in the path internally. The 2 boards are powered by the same supply (and have the same ground point at the power supply).
Any suggestions also as to what we can do to protect this path if we respin this board?
Thanks!
Ron