IMO, I don't feel that you are violating any "good design practices" by leaving the solder mask on these areas - I have done the same thing for many years.

Sounds like you work with good board houses who are looking out for their customer!


Jason Roetz, CID+
Master Designer
Electrical Group, Industrial Controls Division
4201 North 27th Street 
Milwaukee, WI. 53216 
Telephone: 414-449-6397 
Fax: 414-449-7319
[log in to unmask]
http://www.eaton.com/ 
 



-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Upton, Shawn
Sent: Thursday, September 09, 2010 6:06 PM
To: [log in to unmask]
Subject: [TN] PCB Heatsink Pads

I don't think I've seen this covered before.  On a number of layouts that I've done, I've added some top or bottom layer metal round components that might dissapate some heat.  However, I've always left the soldermask over these areas, since it's not a pad to solder to--it's just an attempt to spread some heat, just in case.  [I generally use a "real" heatsink if I know it will make heat.]

However, it seems that a good chunk of the time I get asked by board houses if this is a pad to solder to, and if I made a mistake.  No biggie to correct this (they find plenty of real issues), but I'm wondering if this is somehow in violation of good design practice.

Thanks.

Shawn Upton

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