Different vias dimensions in the same layout

Layout
1

Hi all
In my 2 layers pcb I have routes caracterized by different widths.
Right now I have only 1 dimension for vias though.

small%20via%20question
small%20via%20question1920Ă—960 84.6 KB

Is it ok?
Do I risk overheating?
How can I add a new via format?
Cheers

2

A quick check confirms that you can edit each via on a one off basis. I don’t know about different sizes during placing.

3

You may select the size of a via before you place it, similar to how you select the width of a track from the drop-down “Track:” menu:

image

The selected via size remains in effect until you change it, or re-start the program.

Of course, there won’t be any choices for via sizes unless you specify them in the “Design Rules” menu beforehand.

Dale

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4

In 5.1.2 serch for it in File|Board Setup…

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5

I am used to see vias as being bigger then track. Do you have so wide tracks or so tiny vias?

6

TI has a wealth of information. This one on page 11 talks about via capacities et al.

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7

I often do two things to increase the capability of vias, I realize these cannot be done for all designs because of space.

  1. Increase the ID of the via. This not only increased the circumference (hence increasing the copper connection) but to small amount increased the via copper thickness due to the ability of plating current more easily reaching the center of the via hole.

  2. Overlap the traces and add additional via or vias.

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8

When setting the default trace width for different netclasses, you can also set the via size. If you setup the netclass with the wide traces with a larger via, then when routing a net assigned to the wider netclass the larger vias will automatically be used.

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9

30 mils and 80 mils tracks.

10

My PCB manufacturer accepts tracks 6 mils, annular ring 8 mils (and 10 mils at internal layers).
As I don’t wont to test his technology borders I use tracks from 8 mils (typically 10 mils) and annular ring 10.
My typical vias are 40/20 (and 36/16 when have less space) so look big compered to tracks.
You have vias 30/15. Annular ring of 7.5 would be to small for me.

11

What do u mean saying 40/20, 30/15, 36/16? What does 20, 15, 16 numbers stand for?
Cheers

12

40/20 via means 20 mils diameter hole with pads of 40 mils diameter.
That gives annular ring of (40-20)/2=10mils.

At picture in your first post I see (top bar) that you use vias 30/15 (annular ring (30-15)/2=7.5mils.

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