---
title: "Pin capacitance"
url: "https://maker.wiznet.io/forum/11171"
markdown_url: "https://maker.wiznet.io/forum/11171/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "barrey"
created: "2015-07-10T07:19:52+09:00"
last_activity: "2017-05-04T08:36:22+09:00"
language: "en"
views: 631
replies: 2
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Pin capacitance

## Question

Asked by barrey on 2015-07-10 in Ethernet Chips.

Hello,

There is no information in datasheet about the pin capacitance (in pF) (for the W5300 host bus bus). Is there additional documentation with this kind of information ?

Thank you

M. Barrey

## Replies

### Reply 1 by lawrence, 2015-07-12

Hello, barrey.

There is no details in datasheet.

We handle it with reference Schematic in our web site.

[url][http://www.wiznet.co.kr/product-item/w5300/\[/url\]](http://www.wiznet.co.kr/product-item/w5300/%5B/url%5D)

here’s URL. you can find that zip file on right side var, under the datasheet.

I hope it is what you are looking for.

If any questions or want more information, feel free to ask.

Thank you

Lawrence.

### Reply 2 by barrey, 2015-07-15

Hi,
Thank you Lawrence for your reply, but I already looked at this document, and it’s doesn’t answer my question.
In fact, I have several devices connected to my host processor (the W5300 is one of them), and I had 2 questions :

- check if there are not too much devices connected on the bus, (too much capacitance that would slow down the signal, and too much capacitance compare with the processor capability)

- how to adjust the drive strength of the processor pads (there is a setting on that processor).

Since several devices don’t have any information about their pin capacitance (the W300 is one of them), I simply check with an oscilloscope (I take into account that the oscilloscope probe have his capacitance too ![:wink:](https://emoji.discourse-cdn.com/twitter/wink.png?v=12) ), and I adjust the drive strength. Hopefully, it’s seems that I far from having too much capacitance… ![:stuck_out_tongue:](https://emoji.discourse-cdn.com/twitter/stuck_out_tongue.png?v=12)

By the way, that would be great to have that kind of information in datasheet: we could check this before making a prototype…

Guillaume Barrey

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Source: https://maker.wiznet.io/forum/11171