Where to find these heat conducting DPAK blocks ? - Page 1
Forum section: electronics / projects

author: CookieMonster
author_rank: Contributor
timestamp: December 07, 2021, 06:23:21 pm
content: Hi Guys,I recently saw these heat conducting blocks surface-mounted above an SMT DPAK package.It appears to be a tin tinned copper material - the dimensions are 12x6x4.5mmI already did some research online, but could find anything like these.Does anyone know how these are called or where they can be sourced ?Thanks !

author: Gyro
author_rank: Super Contributor
timestamp: December 07, 2021, 06:34:18 pm
content: I haven't seen those before, it's possible that they are custom. They look to be designed to add thermal mass for pulse operation rather than efficient heatsinking.SMD heatsinks are common however, they might work, depending on your needs. eg...https://uk.rs-online.com/web/p/heatsinks/7124217/

author: CookieMonster
author_rank: Contributor
timestamp: December 07, 2021, 06:36:39 pm
content: Thanks for your reply !Those are the only things I've found too.The point for the ones shown is, that they couple to an aluminium plate to which the PCB is mounted.

author: strawberry
author_rank: Super Contributor
timestamp: December 07, 2021, 06:48:08 pm
content: PCB vias and 2mm thick thermal pad

author: Gyro
author_rank: Super Contributor
timestamp: December 07, 2021, 07:09:57 pm
content: Quote from: CookieMonster on December 07, 2021, 06:36:39 pmAh yes, that makes more sense.It looks like a challenge in mechanical tolerancing. Turning it around, what about blocks mounted on the Aluminium plate which make contact with either the exposed PCB copper area, or the D-PAKs themselves. Either way, you probably need thermal pads, as strawberry says, to take up mechanical variations and ensure decent contact [Edit: and electrical insulation].

author: Someone
author_rank: Super Contributor
timestamp: December 07, 2021, 08:48:29 pm
content: What sort of volume? Nearest off the shelf part would be the SMD screw terminals. Wurth do those on tape for pick and place, say 7466303R

author: CookieMonster
author_rank: Contributor
timestamp: December 07, 2021, 10:56:31 pm
content: Quote from: Gyro on December 07, 2021, 07:09:57 pmThats how its done on the picture I posted. There is a pad that covers both the metal block and the DPAK.Still, I do believe that this would provide a much better thermal conduction than just cooling the DPAK with such a pad.Quote from: Someone on December 07, 2021, 08:48:29 pmProbably not enough to justify a custom part.I wouldn't even know how to pull that off - even if my metal guy could make this part, the main challenge would probably be putting it in a reel to make it suitable for production.

author: thm_w
author_rank: Super Contributor
timestamp: December 08, 2021, 01:24:51 am
content: It doesn't need to go in a reel, can be in a waffle tray. But thats probably more custom work to be done.https://www.youtube.com/watch?v=t8SidZ3wLvQSimilar example is shown in this PDF:https://www.infineon.com/dgdl/Infineon-ApplicationNote_Package_DoubleDPAK_DDPAK-AN-v01_00-EN.pdfWhat about machining that block into the case itself? Or having a epoxied/screwed in piece?

author: CookieMonster
author_rank: Contributor
timestamp: December 08, 2021, 09:44:30 am
content: Quote from: thm_w on December 08, 2021, 01:24:51 amSure, that would work - but it can't compete with the simplicity and elegance of this solution