Oh I get it, just like it sounds, thank you! KennyB -----Original Message----- From: Dwight Mattix [mailto:[log in to unmask]] Sent: Thursday, April 05, 2007 2:29 PM To: [log in to unmask] Subject: Re: [TN] Thermal via's on D2PAK sanded flat. At 02:11 PM 4/5/2007, Bloomquist, Ken wrote: >Hi Kerry, > >Could you please explain "planarized"? That's not a term I'm familiar >with. > >Thanks, > >KennyB > > >-----Original Message----- >From: Kerry McMullen [mailto:[log in to unmask]] >Sent: Thursday, April 05, 2007 10:51 AM >To: [log in to unmask] >Subject: Re: [TN] Thermal via's on D2PAK > >You can also have the vias plugged with a non conductive filler (Peters >does well) and have it planarized prior to plating. Works well. > >Kerry McMullen >Principal New Product Mfg. Engineer >LTX Corporation >825 University Avenue >Norwood, MA 02062-2643 >(T) 781-467-5468 >(C) 508-631-1832 >(F) 781-461-0993 > > > >Barbara Burcham <[log in to unmask]> >Sent by: TechNet <[log in to unmask]> >04/05/2007 12:03 PM >Please respond to >TechNet E-Mail Forum <[log in to unmask]>; Please respond to >Barbara Burcham <[log in to unmask]> > > >To >[log in to unmask] >cc > >Subject >Re: [TN] Thermal via's on D2PAK > > > > > > >I use vias, too. >The vias should be as small as possible. >I use solder paste dots between the via holes so that the solder is not >sucked down the holes in reflow. > > >-----Original Message----- >From: TechNet [mailto:[log in to unmask]] On Behalf Of Frank Kimmey >Sent: Thursday, April 05, 2007 10:51 AM >To: [log in to unmask] >Subject: Re: [TN] Thermal via's on D2PAK > >Kenny, >There are lots of issues to deal with when placing vias under any >soldered component. >We almost always use thermal vias under hot parts to help. > >You will need to calculate a few items prior to completing layout. >1. PCB thickness (higher aspect ratio helps reduce bleed through) >2. Via diameter (larger vias allow more solder to flow through the PCB) >3. Solder availability (solder starvation beneath the part can be an >issue) >4. Final finish and solder process (again, how much solder will go down >the holes) >5. How to keep the backside from being a mess > >Call me if you want to discuss in further detail. >Hope it helps, >FNK > >Frank N Kimmey CID+ >Principal PCB Designer >PCB Programs >Powerwave Technologies Inc >Office 916-941-3159 >Fax 916-941-3195 >Mobile 916-670-0645 >-----Original Message----- >From: TechNet [mailto:[log in to unmask]] On Behalf Of Bloomquist, Ken >Sent: Thursday, April 05, 2007 8:43 AM >To: [log in to unmask] >Subject: [TN] Thermal via's on D2PAK > >Do any of you see an issue with putting thermal via's under the bodies >of a D2PAK? Do you have any recommendations for the number or size or >the via's to help transfer heat to the other side of the board? > >Thanks, > >KennyB > >--------------------------------------------------- >Technet Mail List provided as a service by IPC using LISTSERV 15.0 >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 >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 >----------------------------------------------------- > >--------------------------------------------------- >Technet 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