Need refernces on standard via sizes

what is the min via size can be used?

Hi Folks,

Can anyone refer some links r send some pdf's realted to standard via sizes used.


Rerads
RAME

Re: Min Via Size

Hi Rame,

Who realizez the circuit to yuo declares that the holes can be realized until a 0,3mm. The pad it must be increased the 24mils respect to hole. generally I use holes from 0,6mm and pad from 0.7mm

Re: Min Via Size

Hello

Generally you should try to use vias bigger than minimum size. However for most manufacturers you may use vias as small as 1/5th of board thickness in diameter. As such I'm not sure there are standards for the sizes...

I hope that was helpful.

Re: Min Via Size

The size of a via is driven by several different engineering concerns. There is no such thing as "standard size vias".

For very high frequency circuits, you want to keep the inductance of your vias as small as possible. This translates into small diameter vias. On the other end of the spectrum is a via used for power - it may have to be large diameter to provide enough copper to carry high current without excessive heating.

How small the via can be is determined by how thick the circuit board will be when you are done. Board fabricators call this the "aspect ratio". How large a via can be is determined by the drill and route capabilities of your PCB fabricator.

The size of the annulus of copper you need to use is determined by your drill size. When a via is drilled by the fabricator, he has to use a bit that is 2-3mils larger than the final plated size of the hole - this is to make room for the copper plate inside the hole. He also needs a large enough annulus on both the top and bottom of the board to allow the plating process to proceed properly. Normally this is at least 4mils greater radius than the drill size. For example, you choose a finished hole size of 15mils. That will make the drill size about 18mils and the copper annulus will have to be at least 18mils+8mils=26mils.

One of the largest board manufacturers in the world is Merix. They have a manual available on their website that discusses the physical limitations for manufacturing a board. It is called their "Design for Manufacturabiltiy (DFM) Manual", and you can get it at: **broken link removed**

Re: Min Via Size

Hi House cat,

Thanx for the details and do appreciate for the pdf link you had refer,its really informative.



Regards

Rame

Min Via Size

Well, Mr. House Cat - Thank you for the support. I learned something that I never knew

Re: Min Via Size

The URL of the file Housecat mentioned has changed to:

**broken link removed**

Very usefull for me! Thnx

Re: Min Via Size

A usefull criterion is :

( Via_Diameter - Hole_Diameter ) > 20 mils

Re: Min Via Size

This may be helpful for all.

Raj

Min Via Size

you use from 0.2mm to 0.4mm depends on density and requirements. also you can go to the HDI method where you can use 0.076mm micro vias, but manufacturing will be expensive.

Re: Min Via Size

the minimum via size depends upon the PCB Processing unit also they must be capable of processing the minimum via size that we use in the design
i am using a via size of 0.2 to 0.3mm