---
title: "Ethernet Jack with magnet choice"
url: "https://maker.wiznet.io/forum/15055"
markdown_url: "https://maker.wiznet.io/forum/15055/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "inx onlya"
created: "2023-10-30T12:46:58+09:00"
last_activity: "2023-10-30T17:09:30+09:00"
language: "en"
views: 267
replies: 5
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Ethernet Jack with magnet choice

## Question

Asked by inx onlya on 2023-10-30 in Ethernet Chips.

Hello, I am designing a circuit with W5500 and an Ethernet jack with integrated magnets.
My choices are limited to vertical SMD ones. After a thorough search, I have found one as shown below. However, the internal transformer windings are slightly different from the datasheet recommendations.
Would you think that this is still suitable? Or I have to go with the discrete transformer solution.
![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/9/9d33fbe5e0b738bf7ddaa834b35a39a46beba017.png)

## Replies

### Reply 1 by Eugeny, 2023-10-30

Use the ones with the internal circuit as shown in the datasheet. IMHO this one on the pic is not the best one for W5500 *at least* because it has common RCT/TCT pin.

### Reply 2 by inx onlya, 2023-10-30 (in reply to reply 1)

There is a section in the reference design: [Reference Schematic | WIZnet Document System](https://docs.wiznet.io/Product/iEthernet/W5500/ref-schematic#rj45-with-integrated-transformer-and-connected-ct).
That states that two additional capacitors are needed for the isolation.
Is there any disadvantages of doing this with instructions in this section compared to the modular jack with a discrete transformer?

### Reply 3 by inx onlya, 2023-10-30

My current situation is that I might have to place the Ethernet connector and the W5500 on different boards with pin headers.
Would you think that the Ethernet signal propagation would be at least reasonable via the pin headers?

### Reply 4 by Eugeny, 2023-10-30 (in reply to reply 3)

inx_onlya:

> via the pin headers

I did it in my design and it works properly, but the cumulative trace length is very short and I use high density headers soldered into the board.

inx_onlya:

> Is there any disadvantages of doing this

If there’s a circuit and you make your design according to it then it is supported configuration, and you must expect it to work (if you’ll not make mistakes in adjacent areas of design like routing and component selection).

### Reply 5 by inx onlya, 2023-10-30

Thanks for your help!

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Source: https://maker.wiznet.io/forum/15055