Surface Mount (SMT) Gull Wing DIP Sockets (Frankensockets) - Page 1
Forum section: electronics / general

author: JoeN
author_rank: Frequent Contributor
timestamp: March 27, 2018, 08:39:38 am
content: If bending the pins is too hard for ya...https://www.mill-max.com/new_products/detail/18I guess it might come in handy for production runs that benefit from no through holes but require a DIP package and can accommodate or require a socket. However, I never knew these Frankensockets existed until just now that I decided to throw some dips on a SMT board and wondered if anyone ever made anything like this. For me, bending the pins on far cheaper sockets worked fine.Who might need such a thing?

author: ManCave
author_rank: Regular Contributor
timestamp: March 27, 2018, 08:49:53 am
content: I think you covered the reasons in your post. The issue with modifying non-SMT sockets to do this job is the resulting strength of the pins. The flat-leaded ones will put too much strain on the solder joint (peeling effect) when removing the IC from the socket, while machined pins ones aren't easy to bend and chances are the pins will break.This solution is the proper way of doing it if you want reliable product, want to avoid through-hole soldering process because of a single component you cannot get in an SMT package.

author: langwadt
author_rank: Super Contributor
timestamp: March 27, 2018, 09:08:18 am
content: if you are crazy enough to etch you own pcbs it would save a whole lot of drilling

author: JoeN
author_rank: Frequent Contributor
timestamp: March 27, 2018, 09:45:30 am
content: Quote from: langwadt on March 27, 2018, 09:08:18 amSure, but you can take normal cheap sockets and bend the pins 90 degrees too, at least for hobbyist projects.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 27, 2018, 09:49:46 am
content: Or, for 1-offs, just use normal turned-pin sockets and surface-solder the pins without forming them - a bit more height but quick and easy

author: ajb
author_rank: Super Contributor
timestamp: March 27, 2018, 04:53:43 pm
content: Quote from: ManCave on March 27, 2018, 08:49:53 amAlso, these are machine-placeable, which is the more important factor, unless a high rate of replacement on the socketed parts is expected.You can also get machine pin DIP sockets where the pins end in short stubs just below the frame (and actually float slightly in the frame to accomodate paste flow) which allow you to surface mount DIPs without the increased footprint of the gull wing style socket.

author: Vtile
author_rank: Super Contributor
timestamp: March 27, 2018, 09:20:38 pm
content: "Traditional gull-wing leads permit easy visual inspection of the solder joints from the top of the circuit board (preferred by "military" customers.)"To be honest this is not even a "franken" anything... compared some vintage 'flat pack' CPUs etc.

author: Halcyon
author_rank: Unknown
timestamp: March 27, 2018, 10:34:29 pm
content: Just a thought, wouldn't the solder joints/pads be exposed to more stress when removing DIPs from these sorts of sockets?

author: JoeN
author_rank: Frequent Contributor
timestamp: March 28, 2018, 01:32:47 am
content: Quote from: Halcyon on March 27, 2018, 10:34:29 pmI was thinking that DIP removal is a totally manual thing, so if that is going to be a problem then just write in the service manual to pry it from the side gently with a small flat screwdriver rather than a puller? That way the forces balance out and there is no upward pulling on the board. That's the way I pull DIPs most of the time anyway unless board or component placement makes it impossible because I always have a screwdriver around and rarely a DIP-puller.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 28, 2018, 06:38:58 am
content: Quote from: mikeselectricstuff on March 27, 2018, 09:49:46 amYup. Incidentally, SM-782 and IPC-7351 provide recommendations for this orientation. The pins must be cut straight (normally, DIPs have tapered ends!) and planar, and the pads should be 0.3mm (give or take component density class) outside the MMC position and dimension of the pins (just like any heel/toe fillet), plus whatever extra you want (say 0.5-1mm for extra soldering area).Still not going to be very strong, but there is indeed a best way to go about it.Tim