WIZnet Developer Forum

W5500 circuit - are these resistors needed?

I am working on integrating the W5500 on a circuit. I am using this schematic (w external transformer) http://wizwiki.net/wiki/lib/exe/fetch.php?cache=&media=products:w5500:w5500_sch_v110_use_trans_.png

I am wondering why we need resistors: R13, R14, R15, and R18, R19, R20. They are connected to NC pins.

Can these be left out?

Hi.

We provide to minimum schematic for operation.

R13, 14, 15, 18, 19, 20 is not using. It is fine.

It is not left out

Thank you

So I don’t need them in my circuit, correct?

This reference circuit diagram you used is for separate transformer and RJ-45 jack. Pins 4, 5, 7 and 8 may be used for either additional data transmission or PoE (power over ethernet). You will NOT need these pins if you do not use any of these features. And you will not need those related resistor (for termination) if your network does not use these capabilities. BUT - if you are unsure, leave soldering places for these components on the board when designing it. Again - if you are going to use separate transformer and jack.
Refer here: http://wizwiki.net/wiki/lib/exe/fetch.php?cache=&media=products:w5500:w5500_sch_v110_use_mag_.png

1 Like

thank you for being here.
I have read all topics related to the W5500 PHY. IC in the forum, but i’m still stuck here with this question related to the R13&R14&R15&R18&R19&R20.
I will use the spare pairs(4,5&7,8) as the POE supply terminals, so i was wondering should i use those termination resistors or not ?
even if i will not use those pairs at all what is the theory behind terminate them?

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