Hi Mark, 1. You should read the QFN manufacturer application notes / guide rules 2. Via holes in thermal pads, should be opened both sides 3. The via hols should be layout, symmetrical from the center line of the thermal pad. 4. Avoid via holes in pads termination or between termination pads to thermal pads. For full layout instruction, you can mail me offline. Reuven On Wed, Aug 31, 2011 at 10:52 PM, Mark Larson <[log in to unmask]> wrote: > I am curious how others are handling these parts for soldering. Do you > leave the thermal vias in the slug covered or uncovered with solder mask? Do > you fill with anything? What size hole on a 62 mil board? Tie to all GND > planes or just the back side? Thermal relief the via or bury it in the > plane? > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 16.0 > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to > [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to > [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: http://listserv.ipc.org/archives > For additional information, or contact Keach Sasamori at [log in to unmask] or > 847-615-7100 ext.2815 > ----------------------------------------------------- > -- Best Regards, *Reuven Rokah* Mobile: 972-52-60-120-18 Tele-fax: 97239360688 <http://www.rokah-technologies.com/>[log in to unmask] [log in to unmask] www.rokah-technologies.com ** This e-mail message is intended for the recipient only and contains information which is CONFIDENTIAL and which may be proprietary of Rokah Technologies. If you have received this transmission in error, please inform me by e-mail, phone or fax, and then please delete all of the original files and all other copies exist. ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 16.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------