Solution for manufacturing large quantities if PCB with header/jumper - Page 1
Forum section: electronics / general

author: ebhs
author_rank: Newbie
timestamp: September 14, 2023, 11:47:59 am
content: Hello,We have a project where we must manufacture a large quantity of PCB with 3-pin 2.54mm headers that are used for the configuration pins of an integrated circuit. Each header must have a jumper connected to short 2 of its 3 pins. Those jumpers must be installed on the headers when we ship the boards.For now we install them manually but it is very time consuming.Header example:https://be.farnell.com/en-BE/wurth-elektronik/61300311121/header-2-54mm-pin-tht-vertical/dp/2356154?ost=61300311121Jumper example:https://be.farnell.com/en-BE/samtec/snt-100-bk-t/shunt-bar-2pos-2-54mm-black/dp/2505006?ost=2505006What would be a scalable solution for those ? I've been looking for headers with pre-mounted jumper but couldn't find any.Any clue would be appreciated !Thanks in advance.E.

author: SMTech
author_rank: Frequent Contributor
timestamp: September 14, 2023, 12:16:13 pm
content: How does this possibly take an appreciable amount of time?You could use a slide switch, a dip switch a hex switch (depending on how many of these are on one board and how many independent options they are configuring). You still need to set it, but you save that 5 seconds reaching into a pot of headers and clipping it onto to 2 pins...

author: ebhs
author_rank: Newbie
timestamp: September 14, 2023, 12:38:25 pm
content: Hi SMTech,Thanks for your answer.I'm talking about ~10 jumpers per boards, and a few hundreds of boards, which in the end takes a considerable amount of time

author: zzattack
author_rank: Regular Contributor
timestamp: September 14, 2023, 01:06:31 pm
content: Eliminate the use of any jumper for 'default' binary choices, so that no jumper installed represents the most common choice. Change into 2-pin headers where possible.

author: SMTech
author_rank: Frequent Contributor
timestamp: September 14, 2023, 01:07:09 pm
content: Quote from: ebhs on September 14, 2023, 12:38:25 pmIn that case, may I welcome you to 2023 with your product from 1982...But yes, evaluate all the possible settings and pin counts, trim down where possible, supply jumpers in a bag to enable non-default rarely changed settings. Move configurations to a menu or other soft-setting, use other switches as suggested previously. The correct answer depends on what these settings are, who changes them and why, and what the current process costs you. For example if one installation or installer uses multiple cards and they set them up once, maybe a handset is a good idea or bluetooth or a serial link

author: tszaboo
author_rank: Super Contributor
timestamp: September 14, 2023, 03:16:10 pm
content: DIP switch is an obvious choice, but I would rather place an EEPROM on it, or write a programming script that tells the board the configuration. You can also make a test fixture that has pogo pins on the device that will keep the voltages different when it's in the fixture. There are many ways.You really have to tell us why you were using jumpers in the first place.

author: Ian.M
author_rank: Super Contributor
timestamp: September 14, 2023, 03:29:44 pm
content: Why must the jumpers be on the headers when shipped?Simply make sure that if no jumpers are fitted, the board doesn't harm itself or any usually connected equipment, and supply it with a bag of jumpers and a diagram where to place them. If necessary, add an extra 'enable' jumper that must be fitted to activate the board.

author: asmi
author_rank: Super Contributor
timestamp: September 14, 2023, 06:33:10 pm
content: For options which rarely need to be changed, I use the footprint like the one in attachment. In this case I can still pick-and-place a jumper resistor to a default position, but user can easily change it later down the line by moving resistor to the other side of that footprint. You can pick the resistor size which you are going to be comfortable with and/or your space constaints, I use 0402 because of how cheap they are and how little room they take on a PCB (the screenshot is made from 10 layer board, so the space on it is quite expensive).I used solder bridges for the same purpose in the past, but they have proven more problematic for assembly as I couldn't find a way to short them reliably during reflow into "default" position.

author: ebhs
author_rank: Newbie
timestamp: September 15, 2023, 10:15:28 am
content: Hi,Thanks a lot for all your answers !We actually have quite a lot of constraints on this board, such as:It is a breakout board, so all configs of the main IC must be available, and without a soldering iron (no SMD 0 Ohm resistors)Ultra-low power: we are dealing with below µA currents so we can't afford to add any pull-up/pull-down resistors, that would introduce an unacceptable leakage, or be unacceptably priceySeems to me that we are cornered in kind of a dead end