nRF52840 wCSP BGA strain limit

RE: nRF52840 wCSP BGA strain limit

mmkunz — Fri, 29 Jul 2022 13:10:07 GMT

Thanks Priyanka!

RE: nRF52840 wCSP BGA strain limit

Priyanka — Fri, 29 Jul 2022 06:31:06 GMT

Hi Matt,

I have heard back from our team:
The strain limit is 4000µε (LTPD=3.09% with 90% confidence)

Simplified monotonic bending test flow:

mount daisy-chain IC on specific PCB for bending test.
mount few strain gauges on PCB close to the IC.
bend the PCB and real-time monitor the strain & daisy-chain resistance.
test-to-fail mode: bend the PCB till DC resistance meets failure criteria and record the strain.
test-to-target mode: stop bending when target strain reached and record DC pass/fail results.

-Priyanka

RE: nRF52840 wCSP BGA strain limit

Priyanka — Tue, 26 Jul 2022 06:17:53 GMT

Hi Matt,

I have asked internally regarding this and will get back to you soon. Kindly expect a delay since it's the holiday season and we are short staffed at the moment.

Best Regards,

Priyanka