---
title: "W5500 not drawing power"
url: "https://maker.wiznet.io/forum/15210"
markdown_url: "https://maker.wiznet.io/forum/15210/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "nstansbury"
created: "2024-05-02T14:03:03+09:00"
last_activity: "2024-05-03T07:07:56+09:00"
language: "en"
views: 91
replies: 3
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 not drawing power

## Question

Asked by nstansbury on 2024-05-02 in Ethernet Chips.

Hi,

I’ve assembled a new prototype board with the W5500 and it appears to never power up. I’ve double checked all the connections and I get 3.3v power where I expect it right up to the decoupling caps and after that nothing, and nothing on the 1.2v rail.

Ethernet cable and switch port is confirmed good, with auto-neg enabled, but the link light on the switch never illuminates.

The LC of my crystal is 18pF so allowing for 5pF Cstray, the crystal caps seem reasonable. Sadly I don’t own a oscilloscope that will measure up to 25Mhz to 100% confirm this.

The schematic was based on the reference design & Adafruit’s Ethernet FeatherWing.

I’ve attached a screenshot of that part of the board layout and schematic. C19 I get a clean 3.3V after that nothing.

Could this be a bad chip or is there something else I can check through first? Any thoughts are much appreciated.

[![Screenshot 2024-05-02 at 15.01.06](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/d/d96e44d9eab0b76a62ef0c17ce7dd847bf241cee.png) Screenshot 2024-05-02 at 15.01.061943×730 15.1 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/d/d96e44d9eab0b76a62ef0c17ce7dd847bf241cee.png)

[![Screenshot 2024-05-02 at 14.40.13](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/2/2da8679c5a71c3b17f6ce92a4e8c51b042106184.png) Screenshot 2024-05-02 at 14.40.131141×1257 182 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/2/2da8679c5a71c3b17f6ce92a4e8c51b042106184.png)

## Replies

### Reply 1 by Eugeny, 2024-05-02

Mistake in connecting RX. What state reset signal is in? And how did you assembled, and at which temperature?

### Reply 2 by nstansbury, 2024-05-02

Hi, what are you seeing about the RXn connections?
Reset is pulled up to 3.3v at power on.
Board was reflowed in a reflow oven and hit the correct solder profile through out. I’m getting continuity on expected circuits.

### Reply 3 by nstansbury, 2024-05-03 (in reply to reply 2)

> Reset is pulled up to 3.3v at power on.

Hmm actually that’s not quite true double checking it. The 3.3v regulator feeds the 3.3vD/VDD power plane via a 22uF decoupling cap and that rail is only at 0.6v, which won’t be enough to be seen high I’d guess. This must be an issue with the 3.3vD power plane.

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Source: https://maker.wiznet.io/forum/15210