Pin socketing voltage reference cans? - Page 1
Forum section: electronics / general

author: julianhigginson
author_rank: Frequent Contributor
timestamp: May 10, 2017, 04:41:12 am
content: I am about to get started on LM399A volt reference journey with the calibration club.The plan is to have a couple of reference boards finished/aged in boxes to compare against each other and other peoples references once they stabilise.And maybe one day when I have at least a bit of practical experience with the 399A circuits, I'd also like to do something with an LTZ1000 because that's the big one, and why not go all the way?One thing I'd like to try, would be to get myself some machined pin sockets so the 399s can be attached/detached and swapped between reference boards without soldering. But I'm a little leery of what could happen here with the connection possibly not being as solid as a soldered one, and surfaces oxidising over time.Has anyone tried this before?

author: cellularmitosis
author_rank: Unknown
timestamp: May 10, 2017, 07:39:36 am
content: I'm curious to know if there is a TO-46 socket as well!In a pinch, of course, you can just use a 2x2 header:

author: The Soulman
author_rank: Super Contributor
timestamp: May 10, 2017, 09:23:34 am
content: http://www.ianjohnston.com/index.php/onlineshop/10-ch-lm399-testing-detail

author: julianhigginson
author_rank: Frequent Contributor
timestamp: May 10, 2017, 11:21:11 am
content: cool! I actually had a quick look for a TO-46-4 socket first, but no luck.*EDIT* though maybe this is OK if you have the right footprint already or are doing your own board?https://www.digikey.com.au/products/en?keywords=ED90274-NDI was thinking standard square pin header sockets might be a bit big for these pins, and I'm looking at using a board someone else did that won't fit a 2x2 0.1" socket... so figured machined pin IC socket broken up into separate pieces would be the go. But good to see standard square header sockets working, at least for a bulk burn in.

author: David Hess
author_rank: Super Contributor
timestamp: May 10, 2017, 03:06:59 pm
content: I like using collet socket pins cut out of a SIP and soldered flush into the printed circuit board. Mechanically they work well but in this application I would worry about thermocouple effects.

author: Kleinstein
author_rank: Super Contributor
timestamp: May 10, 2017, 03:23:16 pm
content: With the LM399 there is quite some heat flow through the pins. So one can have some thermal EMF from the socket and the heat flow may not be that stable reproducible. A few DMMs have a LM399 type reference in a socket, so it works, if one really needs it.The LM399 does not need a really critical support circuit. So there is not that much use in having one circuit to test more references. usually it is keeping the reference and the support circuit together as one unit. It is also only 4 pins, so soldering / unsoldering is not that difficult if really needed.

author: Andreas
author_rank: Super Contributor
timestamp: May 10, 2017, 07:14:44 pm
content: Hello,yes I tried sockets.But I cannot recommend that. Especially with devices with very hot feet. (like LM399)You can see the difference of my LM399#3 the first days with socket and after wild jumps I directly soldered the device in.-> much less noise.See: LM399 thread:https://www.eevblog.com/forum/metrology/lm399-based-10-v-reference/msg1142287/#msg1142287Also my K2000 (with soldered reference) is much more stable than the HP34401A (socket). (day to day at equal temperature).It was even worse before I used DeOxit for the socket.So if you really want to go below 5-10ppm stability a socket is a no-go.with best regardsAndreas

author: julianhigginson
author_rank: Frequent Contributor
timestamp: May 10, 2017, 11:54:51 pm
content: aaah, ok. So, if I ever make a board just for bulk burn-in, rather than direct use, like ianjohnston.com then pin headers can work for that, otherwise soldering shouldn't be an issue.thanks all!