I want to make a test device which can route network inputs to one output. For example it could sit between two computers and a network switch. The TS3L301 looks promising, but I am unclear about the differential signal pairs and this device.

The drawing in the datasheet only shows it attaching to a phy, I want it to be between devices. Can I get away without using magnetics here? What about with a POE signal device?


              |                 |<------+Input 1
Output<-------+     TS3L301     |        (7..0)
(7..0)        |                 |<------+Input 2
              +-----------------+        (7..0)

This is just standard ethernet. Each pair should be a LVDS signal, though when using POE the differential pairs would be at different relative voltages. How does this work when the signals aren't actually referenced to anything in my circuit? Does that happen internally?

The datasheet for the TS3L501E says "This device can be used to replace mechanical relays in LAN applications" which would make me assume this would work. The TS3L301 datasheet doesn't say this. Are there major differences between the two devices? I prefer the package of the TS3L301.

  • \$\begingroup\$ There are no reference drawings in either schematic that I could find, You will likely not be able to inject a powered POE signal directly into an analog mux. \$\endgroup\$
    – crasic
    Nov 18, 2015 at 0:25

1 Answer 1


You'll probably need to use transformer isolation with this. And there is no way that it would work with POE unless you use transformers to extract it and re-inject it.


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