7mm height board to board connector - Page 1
Forum section: electronics / projects

author: PeterFW
author_rank: Frequent Contributor
timestamp: April 12, 2015, 03:16:32 am
content: Greetings!There are two board, they should be spaced 7mm apart.There is a bit of wiggle room of +-0.3mm, everything between 6.7 and 7.3mm will do but 7mm would be perfect.It not possible it could be a 7.8mm spacing and it must not be less then 6.7mm.One side has to be SMD but it can have alignment pins, the top board can have holes but it can not be soldered from above.The bottom board has all the room in the world.It should not be something very exotic and it will be hand assembled.I need two interconnects, each with 16-22 pins, rather coarse, not fine pitch.Low speed, no current to speak of, low voltage.The best connector i could find and could buy in quantities of 5 was a TE Micro-MaTch, but they are a tiny bit too flat.Does annoone have a suggestion?Greetings,Peter

author: wraper
author_rank: Unknown
timestamp: April 12, 2015, 10:25:49 am
content: 1.27 mm pin pitch header connectors should be available in this height.

author: mariush
author_rank: Super Contributor
timestamp: April 12, 2015, 10:55:07 am
content: Maybe you should also consider FFC / FPC connectors, you know those very flat connectors in which you shove a ribbon cable.It may be more expensive considering you'd also need to buy the ribbons but it may be possible to simplify your design to use one pair of connectors and a ribbon cable with 40-60 traces instead of two pairs of connectors.May also make more sense from a reliability point of view (vibrations, oxidation of connectors, etc), a ribbon should stick inside the connector and remain there for long time.Seehttp://uk.farnell.com/ffc-fpc-board-connectorsandhttp://uk.farnell.com/ffc-fpc-flat-flex

author: ajb
author_rank: Super Contributor
timestamp: April 12, 2015, 12:44:48 pm
content: Could you do surface mount pin headers and bottom-entry socket headers? Should be able to get any height you want with the proper length pins.

author: Christopher
author_rank: Frequent Contributor
timestamp: April 12, 2015, 01:10:16 pm
content: Samtec do a good range but very pricy

author: PeterFW
author_rank: Frequent Contributor
timestamp: April 12, 2015, 02:44:43 pm
content: Hello everybody and thank you for the replys!Quote from: mariush on April 12, 2015, 10:55:07 amI thought about something like that but the connecters will be used to align the boards to each other and, to so some extend, hold them in place.They will be fixed with screws as well but not on that part of the board, very bad idea, i know.If i can not get away with it, i will add some screws.Quote from: ajb on April 12, 2015, 12:44:48 pmDING! DING! DING! We have a winner!I have seen them, i knew about them but i forgot about them.They could solve another problem i had by creating one more.I will have to think about that for a while

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 12, 2015, 09:33:58 pm
content: Sounds like one of those problems where the solution is worse than its cause -- the best way to avoid these is to do some component and connector choice, early in the PCB design cycle, and pass that along to the mechanical design as early as possible. I'm guessing the height limitation is because you're locked in by a now-existing mechanical constraint?Sage advice, but I know it's not very helpful at the moment...Tim

author: PeterFW
author_rank: Frequent Contributor
timestamp: April 13, 2015, 12:13:08 pm
content: Quote from: T3sl4co1l onTodayat 07:33:58 AMNo worries, i do not have a board routed, no set enclosure or components placed.I do however have pre-selected a enclosure wich will fit everything nicely, but i would like to leave as much room as possible.The idea is, a somewhat modular handheld unit for various projects with two boards.The top board has everything on it, display, buttons, logic, power supply and storage.The bottom board will be the "prototyping area" were the expansion board will be placed.The 7mm board spaceing is governed by the internal case height, the bottom mounting pillars allready in the case, the board height and the spacing of the top board to the case face wich should be 3mm, the display is 2mm high and i would like a bit of room on top.That leaves me with about 7mm between the boards:The main goal is to make this fit with standard components, that includes standard thickness FR4, no modifications to the enclosure besides the cutouts for the buttons and display, trace with/spacing of 0.3mm and two layers only.That way every board house can do these.The display sits flush and covers 3/5th of the top board, that is the reason nothing can be soldered there. It covers 2 of the the screw holes as well, so there has to be a bit of retention force on the board to board connection, i am trying to include two additional threadet pillars between the boards in case the board connectors provide not enough though.