Fitting a socket with the wrong footprint - Page 1
Forum section: electronics / beginners

author: LoveLaika
author_rank: Frequent Contributor
timestamp: October 08, 2020, 03:44:59 am
content: I was working with a TO99-8 can op-amp, and I used a custom footprint. I aligned it with a TO99-8 model from KiCAD and it fits perfectly. However, I had issues with my board when I used it with a socket. I honestly don't know where it's at on Digikey, so I'll post a link to it (or something similar) on Amazon below. It turns out that my TO99-8 footprint will fit the op-amp, but it will not fit these TO99-8 sockets. The pins of the socket are farther out than the footprint. Through a little force, I was able to maneuver the pins to 'fit' inside my footprint, but because the pins are bent inwards slightly, the socket will not sit flush with the board. I was able to solder the pins to the board, but with the way the socket is mounted, would it cause problems? I'm using the socket because it would make it easier to switch out op-amps as needed in my circuit.https://www.amazon.com/Propart-USB/dp/B07F7H7C4NOn a related note, what should I search for on Digikey to find similar parts? I'd like to find the recommended land pattern for future footprints.

author: drvtech
author_rank: Regular Contributor
timestamp: October 08, 2020, 07:03:07 am
content: Can you use single pin sockets? Harwin do them. Search for Harwin single pin sockets as a starting point

author: magic
author_rank: Super Contributor
timestamp: October 08, 2020, 07:42:23 am
content: The cheapest and "availablest" source of single pin sockets in small quantities that I found is to yank them out of DIP8 or SIL40 sockets with pliers

author: Doctorandus_P
author_rank: Super Contributor
timestamp: October 08, 2020, 02:16:59 pm
content: Sometimes the pins are bent outward to fit into a standard DIP-8 socket.It's pretty easy to bend the pins by first sticking them through a piece of matrix board, then bend them so the exiting parts are perperndicular to the matrix board and cut them all to the same level.If you have to do a lot of them, you can glue a match or toothpick to the matrix board to more easily cut the pins to the same level.Bending the pins outwards instead of inwards also increases the mechanical stability.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: October 08, 2020, 03:32:21 pm
content: You know, I did have to use single-pin sockets for something similar before. Thanks. I didn't really recall that idea until you guys reminded me, as long as the footprint's holes will accommodate the pins. Glad I made a spare board just in case. Single-pin sockets won't have any Teflon protection like the sockets, but at least it makes swapping out op-amps easier.Nevertheless, this was a mistake that I made before, assuming that the socket footprint will line up with the TO99 footprint. I'd like to try and not make that mistake again.

author: drvtech
author_rank: Regular Contributor
timestamp: October 08, 2020, 05:56:24 pm
content: Way back (1982) we manufactured a product with a 42 pin DIP chip. We used to buy the individual sockets which were delivered on a carrier - an aluminium plate with the same pattern of pins as the chip. We soldered this into the PCB then unplugged the aluminium thing and plugged in the chip. I was trying to remember who supplied them but it's rather a long time ago! Probably Augat as they were turned pins just like the ones on a standard DIP socket.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: October 08, 2020, 07:07:51 pm
content: Thanks for the help. Looking at what's on Digikey/Mouser, I found this lovely little set.https://www.mouser.com/ProductDetail/Mill-Max/917-47-208-41-005000?qs=5aG0NVq1C4zZJBYftO%252BvrA%3D%3DLooking at my KiCAD footprint, my TO99-8 footprint was set for 0.2 inches in diameter, pin to pin (5.08 mm). Going by the standards shown in the datasheet, I think I might have been working with mounts that had a diameter of 0.23 mm (5.842 mm). That's quite a big difference.

author: Wendy_Preston
author_rank: Contributor
timestamp: October 09, 2020, 07:38:23 am
content: Quote from: drvtech on October 08, 2020, 07:03:07 amHere's a link to the relevant catalog section:https://cdn.harwin.com/pdfs/Harwin_PC_PCB_Sockets.pdfHopefully you can find something suitable in here. If you look it up onwww.harwin.com, then you can see which authorised distributors have stock - we sell through the likes of TTI, Digi-Key, Mouser, Farnell, RS and some others.If you need help with selection or use, our Experts can help:https://www.harwin.com/contact/.Wendy