[PCB_FORUM] Re: Thermal Pad Design

Here is ours (probably not updated since the sixties):

    ID  = drill size + .020" (NOT Finished Hole Size)

OD is based on a table:
    ID range        OD
    ------------    ----------
    .001 - .049"    ID + .020"
    .050 - .149"    ID + .030"
    .150 - .299"    ID + .040"
    .300+           ID + .050"

4 gaps at 45°
    GAP = ( ID + OD ) * .2 (Rounded to nearest .001")

I could not point to an IPC standard this is derived from as it most likely 
predated IPC Design Standards :)

Good luck :D

--
George Patrick
Tektronix, Inc.
Central Engineering, EDS Applications Support
P.O. Box 500, M/S 39-512
Beaverton, OR 97077-0001
* 503-627-5272 (voice)     * 503-627-5587 (fax)
http://www.tektronix.com<http://www.tektronix.com/>    
http://www.pcb-designer.com<http://www.pcb-designer.com/>

"Off-Grid and Proud of it!"

-----Original Message-----
From: icu-pcb-forum-bounce@xxxxxxxxxxxxx 
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of jeff
Sent: Tuesday, September 09, 2008 07:19
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Thermal Pad Design


Could I get some feedback on what is being used for a thermal pad on a negative 
inner layer for component through holes( not vias)?
What ID is used over the finished hole size? And What OD is used over the ID?

Jeff

Other related posts: