Dave, I always suggest reading the manufacturer's information. Philips should know how to use their own parts. Please visit ............ http://www.semiconductors.philips.com/acrobat_download/various/Surface_mount_reflow_soldering.pdf On page 16 they discuss the recommendations for large pads and thermal attachment. The numbers are 20-35%, not 70%. remember, this may change by component manufacturer, so the other guys may be right about 70%, but for the components they are using. Good Luck Steve Mikell [log in to unmask] > ----- Original Message ----- > From: "Dave Seymour" <[log in to unmask]> > To: [log in to unmask] > Subject: [TN] SO8 with Heatslug > Date: Tue, 28 Mar 2006 10:30:33 -0500 > > > Currently using a Phillips part, > > http://www.semiconductors.philips.com/pip/NE57814DD.html > > This is a standard SO8 package with a large "heat slug pad" under the part. > > During reflow the part is floating off center and causing shorts to the > lead pads. > I believe this because of the the volume of paste in the heat slug area > is lifting the > part up and surface tensions take over. > > I have a call into tech support at Phillips, but I figured I would query > while waiting for a call back. > > What is the recommended volume of solder paste under this device ? > > What is the recommended solder mask opening(s) under this device? > - Something like 4-6 smaller opening over a continuous top side > ground plane? > > What is the recommended paste printing pattern under this device? > - match the soldermask openings? > > Does anyone have experience with such a device? > > Thanks, > > Dave > > > -- > Dave Seymour, CID+ > Catapult Communications Inc. > 800 Perimeter Park Dr, Suite A > Morrisville, NC 27560 > > Direct: (919)653-4249 > Main: (919)653-4180 > Fax: (919)653-4297 > > [log in to unmask] > -- ___________________________________________________ Play 100s of games for FREE! http://games.mail.com/ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------