My current layout consists of two 16 pin (8×2) 2.54mm pitch (shrouded) headers. One is for an 16×2 LCD screen and the other will be for a button interface as well as status LEDs which will be mounted on the front panel. Size is an issue and the headers are taking up way too much space on the PCB. I'm not even using all 16 pins on either of the headers – I chose to go with 16 to make it easier cable setup for the 16 pin LCD (Scientific, I know), I'm actually only using 12 for the LCD and 10 for the UI. I also liked the fact that its the same parts for both headers.
What would be my best option for something size and cost efficient? Would it be better to look for a smaller pitch or a different style of connection all together? Is flex cable a viable option? I've never used it and what I've seen of it, it looks custom with its odd shapes and connectors. Or should I just drop my current headers down to the actual pin sizes I actually need?
Best Answer
To save space on the PCB, you could use Flexible flat cable (FFC) (also referred to as Flexible Printed Circuits, or FPC)
AFAIK, they have a limited plug/unplug life, but are okay for a few operations.
As well as traditional electronics distrubutors, Internet resellers (ebay, Aliexpress, etc.) sell a large range of FFC parts, in modest quantity at lower cost.
Of course, you still have the problem of choosing the number of conductors.
The lower-prices are typically for many-off quantities. Also you might want to reduce your BoM variety. So might prefer to choose a single part for both connections. You may also prefer to retain some flexibility in future, so you might increase the number of pins above your current minimum.
The smaller pitch cables have lower current carrying capacity (though adequate for many applications), so you might want to allow for a several pins for power and ground.
Some of the sellers listed on Chinese sales sites will make custom sizes.