Electronics Forum | Thu Mar 28 13:19:14 EDT 2019 | davef
There is no industry standard for BTC stand-off height. "IPC-7093A Design and Assembly Process Implementation for Bottom Termination SMT (BTC) Components" just finished "Final Draft for Industry Review" in December 2018. It mentions stand-off height
Electronics Forum | Wed Mar 27 04:32:49 EDT 2019 | pavel_murtishev
Charliem, Thank you for the input. Following this logic, in case if there are no soldering issues, pad coverage and voiding levels are within acceptable limits and a gap between BTC and pad let us say 200um, this could be accepted, right? IPC-A-61
Electronics Forum | Fri Jul 27 09:47:20 EDT 2018 | davef
Adding to Rob's suggestions ... One of the theories about voiding in thermal / ground pads of BTC is: Solder starts melting at the edge of the pad and moves inward towards the center of the solder mass. This traps flux volatilizes. So, there needs t
Electronics Forum | Tue Mar 01 15:13:22 EST 2011 | felixgutierrez
Hi Everyone. I would like your input in regards to lead free solder paste lead free. Which one is the most reliable solder for BGA's and BTC's (QFN). I have used different type of solder and on some of them i get big voids on BTC's and other one i g
Electronics Forum | Fri Jan 18 14:39:07 EST 2013 | davef
Main issues with LGA voiding are: * Design * Material selection * Thermal recipe For design, loo here http://blogs.smtnet.com/smt/other/qfn-btc-design-guidelines-thermal-pads-etc/ BR, davef
Electronics Forum | Fri May 17 14:56:21 EDT 2013 | davef
There's not supposed to be any effin 'drain hole.' Where's you get that from? Read this: http://blogs.smtnet.com/smt/other/qfn-btc-design-guidelines-thermal-pads-etc/ BR davef
Electronics Forum | Tue Jul 04 20:31:21 EDT 2017 | davef
If you want in, 5-21h Bottom Termination Components (BTC) Task Group is in "Working Draft" revision from "A" to "B" of IPC-7093 - Design and Assembly Process Implementation for Bottom Termination SMT Components
Electronics Forum | Tue Apr 30 12:11:05 EDT 2019 | slthomas
That's a good summary and the only thing I would add to that is maybe to include an image of the land pattern in your collection. Some of these asymmetrical parts are just about impossible to provide all of the dimensions for. For instance, who want
Electronics Forum | Tue Apr 30 14:56:43 EDT 2019 | SMTA-Joe
Thanks for the suggestions. This seems like the way I'll have to go; create my own database and hope something--one day--comes up the same specs!
Electronics Forum | Mon Jul 22 13:19:31 EDT 2019 | davef
While we're are it, here's a link to a recent FORUM thread that talk's about BTC standoff height: https://smtnet.com/Forums/index.cfm?fuseaction=view_thread&CFApp=1&Thread_ID=21852&mc=9
