Part Number: TS3L501E
I am using the TS3L501E for multiplexing two ethernet paths to a single PHY chip. The PHY chip used is LAN8710A from Microchip.
I am currently testing one of the paths and I have issues with that.
Before using the TS3L501E we had an RJ45 connector and a magnet after that with its secondary centers tapped to 3.3v, and on the PHY side also the RX/TX signals are pulled up to 3.3v.
Now after placing TS3L501E the device is not discovered in the network.
My doubt is towards a few possible problems please give me advice that which one should be the cause, please note that as we have manufactured the boards I can not change many things all at once so it is crucial for me to know the main cause of the problem.
1- In PHY datasheet it is mentioned that: "LVCMOS Variable I/O voltage range: +1.6V to +3.6V" and in TS3L501E it says: "Differential (LVDS, LVPECL) Signal Switching" is there a problem here?
2- as the center taps of the magnet as well as the input of the PHY (8710 chip) both are pulled up to 3.3v, and the VDD of the TS3l501E is also 3.3v, I thought that some clipping might occur. As in the TS3L501E datasheet the recommended switching voltage is between 0 and VDD=3.3 v.
If the problem is one of these what should I do? Does Ac coupling at input or output of the MUX help?
Hello Mike, There are a series of things that could be causing these issues. Could you share a schematic with us so that we can better evaluate what the problems might be? Could you also provide some scope captures of the output from our switch. To address question 1, our switch has the ability for LVDS (differential signals) but they do not have to be used in that manner. The reason we label this switch as Ethernet LAN switch is because the specs for it matches the applications. However, this switch can also be used in other applications as well.
Another way to set up the switch can be seen in the previous E2E Post below:
Thank you, Louie
In reply to Louie:
Thanks for your reply.
Attached is my handwritten approximate schematics. Please give advice.
In reply to Mike Brown24:
Hello, The above looks reasonable to me, assuming that you are switching between network #2 and whatever is on the side of the magnetics. Louie
Yes, you are right. TS3L501E is not able to guarantee signal performance when the analog input or output signal is higher than VDD.
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