Hamid A. Wasti wrote:
One off topic question: Why would you ever want a via to connect to a power plane with a thermal relief? The thermal relief is to allow you to heat up the pins of an IC as you solder them in a through hole pad that is connected to a plane.

Further to this (somewhat harking back to the old days - process tends to improve over time) there is quite a deal of XY expansion in the copper planes, especially during wave soldering, which can lead to cracks forming at the knee (where a copper plane turns 90degrees & continues down the hole). This is more prevalent in plane to hole connections than when compared to a small track (or multiple small tracks i.e. thermal relief) are used. Yes a thermal relief also allows mechanical strain relief in this situation.


Of course, we all want less inductance in those vias & so there comes the trade off...

--
Regards,

Dom VK2JNA

Dom Bragge, CID MIEEE  | Silverbrook Research PL, PO Box 207
Snr PCB Layout Engr    | Balmain NSW 2041, AUSTRALIA
Ph +61-2-9818-6633xt163| [EMAIL PROTECTED]



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