Connecting without a board mount

[shaun39]

Looking to apply an nRF52 chip in a wearable device... ideally without mounting it on a board.

Is that remotely feasible?

It would still be necessary to connect to 12 GPIO pins (alongside DC/DC for power supply). These connections would ideally be 0.1mm diameter cable, directly to the nRF52 chip. (This is a wearable application where the chip won't be collocated with the battery and sensor.)

How would you go about soldering or otherwise fixing 0.1 mm (or finer) cable to the pins on an nRF52 chip directly? Are there any examples of this being done?

[shaun39]

Thank you awneil!

That would seem to settle the matter at a practical level (I'm curious whether anyone has seriously attempted this or if there's a very good reason not to try?).

Follow up question r.e. a flexi-PCB (seemingly the best solution here), where are the best places to design and purchase a flexi-PCB compatible with an nRF52 chip? And in the context of a prototype/ proof of concept (so just a few dozen PCBs initially)?

Are there any generic flexi-PCBs appropriate to use in a case such as this (only real requirement: breaking out GPIO pins).

[awneil]

shaun39 said:

if there's a very good reason not to try?)

Apart from the plain impracticality of doing it at all, I don't know how you'd manage the impedance control for the antenna connection.

Flexi PCB design is a specialist area, and doing it for RF would be a specialisation within that.