One RJ45 or Two RJ45?

If our product requires either LAN or IMP depending on the country, could Imp share PHY / RJ45 with other LAN controller, so our product could have only one RJ45 connector? CPU would mux the MAC data to PHY on boot-up, so only one MAC (either Imp or LAN chip) will be connected to the PHY / RJ45.

Is this imp005? The imp005 uses the standard RMII interface to communicate between (internal) MAC and external PHY. So if you can switch RMII signals (they’re fairly fast), you can switch between imp005 and an alternative LAN chip. However, that seems a pretty unusual thing to want to do. Could you go into more details of the problem you’re trying to solve?


The other way of doing this is to put a switch chip in your design, eg:

This way, you connect both RMII interfaces directly to the switch, and use one of the PHYs on the switch to go to your magjack. Both can be active at the same time.