---
title: "External Magnetic Routing Review"
url: "https://maker.wiznet.io/forum/14879"
markdown_url: "https://maker.wiznet.io/forum/14879/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "Vien Huy Nguyen"
created: "2023-04-20T01:33:27+09:00"
last_activity: "2023-04-24T06:32:47+09:00"
language: "en"
views: 382
replies: 6
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# External Magnetic Routing Review

## Question

Asked by Vien Huy Nguyen on 2023-04-20 in Ethernet Chips.

Hi,

Could you please let me know if my routing is good, or how can I improve it?

I have to use M12 connector for Ethernet connection, can’t find any reference layout for it. Two big extra holes are for plastic inserts for mechanical support.

Trace thickness: 10 mil
Distance between traces in the same pair: 8 mil
Length:
TX+: 855.669
TX-: 812.868
RX+: 431.944
RX-: 417.408

[![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/1/1c7b62fb04dae86e2d0731ed8984d4fe1888e482.png) image1269×889 65.7 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/1/1c7b62fb04dae86e2d0731ed8984d4fe1888e482.png)

## Replies

### Reply 1 by jaden, 2023-04-21

Hi!
Could you show me your whole schematic of W5500?

### Reply 2 by Vien Huy Nguyen, 2023-04-21 (in reply to reply 1)

Hi Jaden,

Thank you for the reply. Here is the schematic
[W5500.pdf](https://maker.wiznet.io/forum/legacyFile.asp?path=rDCgOqxbns4mlDlJF4I9PoG3tGG.pdf) (300.0 KB)

The screenshot is the part where four wires coming to the magnetic as shown in the pdf file.

The pinout of the connector is here:

[![900001136-5](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/1/175c4c89e8f1cd1c12106839791a94b6033034f1.jpeg) 900001136-5837×462 73.8 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/1/175c4c89e8f1cd1c12106839791a94b6033034f1.jpeg)

### Reply 3 by jaden, 2023-04-24

Hi there!
I saw the schematic and have a few questions.
L1 (33uH) is a power inductor. I recommend using a bead to isolate 3V3D and 3V3A. Is there a reason why you used a power inductor?

And case of M12 connector, you can design with any connector, but we can only guarantee optimal performance when using RJ45 jacks and cannot provide technical support otherwise.

### Reply 4 by jaden, 2023-04-24

Also I recommend connecting the Link (pin 25) and ACT (pin 27) of the w5500 for debugging and status checks.

### Reply 5 by Vien Huy Nguyen, 2023-04-24

Hi Jaden,

I will change L1 to a ferrite bead, and connect LEDs to pin 25 and pin 27.

I am facing a difficulty in routing from the magnetic to W5500. The TX pair is crossing the RX pair. It is recommended not to use vias for differential pairs, so I run TX under the magnetic; but now the two TX traces in the TX pair cross and I cannot connect the other trace to R8. Please see attached screenshot.

[![Capture](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/0/0d84eae05f5366bd4070cea58e3661b7620916e8.png) Capture1346×890 27.2 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/0/0d84eae05f5366bd4070cea58e3661b7620916e8.png)

### Reply 6 by jaden, 2023-04-24

If the issue is not solved through component replacement, route with minimal use of via and shield the via to GND.

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Source: https://maker.wiznet.io/forum/14879