---
title: "W5500 stop working at -40C"
url: "https://maker.wiznet.io/forum/14960"
markdown_url: "https://maker.wiznet.io/forum/14960/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "rizwankhalid"
created: "2023-07-04T16:08:47+09:00"
last_activity: "2023-07-04T16:33:57+09:00"
language: "en"
views: 297
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 stop working at -40C

## Question

Asked by rizwankhalid on 2023-07-04 in Ethernet Chips.

Hello,
I have encountered an issue with the W5500 ethernet IC. During our environmental testing, we subjected our product to a temperature of -40°C for 4 hours. Afterward, we noticed that the W5500 is not functioning. The microcontroller that is operating W5500 show there is no W5500 IC.
W5500 IC stop working totally.
I have two questions regarding this situation:

1. What could be the reason behind this problem occurring?

2. Could you please provide guidance on how to resolve this issue?

## Replies

### Reply 1 by Eugeny, 2023-07-04

Please share:

- if W5500 does not work even after you increased the temperature to normal 25C;

- what exact procedure you used to freeze the whole device, in particular temperature profile graph and humidity reading, if you had been opening the test chamber when there’s temperature < 0C;

- the full BOM of the parts used on the board which were subjected to -40C - with manufacturer part numbers;

- material PCB is made of;

- general device photo and circuit diagram of the device.

---

Source: https://maker.wiznet.io/forum/14960