FCC certification - is there a requirement for calibration of each PCB (to compensate for PCB manufacturing variations) ?

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
ShLi_2270861
Level 1
Level 1

Hi,

In our design we are switching from using an external BLE Module (past) to our own PSoC 4 BLE solution (future) where we used the PSOC withcertified BLE stack plus our own custom firmware.

Also we use the cypress recommended design antenna.

We will of course run the FCC certification and familiar with the process for BLE modules.

I heard that when as part of FCC requirements developing your own PCB then you might need to run a calibration process in production for each PCB to compensate for PCB manufacturing variations.

I am sure that from functional point of view we don't need it.

I just wonder about the regulatory requirements.

Can someone confirm / disproof this?

If the answer is yes then can you point to the location of this FCC requirement?

If the answer is yes can someone please explain what is the procedure?

Thanks,

Shachar

0 Likes
1 Solution

Hi Shachar,

Thank you for explaining very clearly.

Not aware FCC requiring a calibration process in the manufacturing to control the variation.

Usually, when the pass margin is good, the customer need not care about the part to part variation. However if the margin is small, it is recommended to check output power level in the production line is less than that of the ample certified for FCC. A 6 dB margin in emissions is usually good and 3 dB margin is not bad. Anything less than that is a risk.

However in most cases where the trace length is small and the tuning components have good tolerance, the variation is unlikely to be big enough to be concerned about.

Thanks

Ganesh

View solution in original post

4 Replies
VenkataD_41
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hi Shachar,

For FCC, you may reuse a module certification, however, the end product still needs to go through the FCC 15 subpart B test. ISED/IC for Canada follows FCC practice.

For CE, all the conducted test cases of EN300328 can be inherited from the modules test report. Any radiated test cases under EN300328 or ESD test cases under EN301489 must be tested with end products

End customers can reuse the modular approval of EZ-BLE modules in Japan or South-Korea. No further RF testing is needed for the end product when it uses a certified module.

All system level tests like ESD, EMC and SAR, when required, should be tested with the end products.

Thanks

Ganesh

0 Likes

Hi Gani,

Thanks for your answer. However I think you may have misunderstood me:

We will run full test and certification of our product from the production line.

But we only test a handful of samples - what about the thousands of units in mass production? They are "identical" to the samples tested for FCC regulations, however when manufacturing so many units, some small varations can arise, like pcb thickness tolerance, traces width tolerance etc.

Do I have to do anything for these manufacturing tolerance variations or assume this is considered OK?

"Do anything" - I mean like some tuning / calibrating each and every unit in mass production?

Thanks,

Shachar

0 Likes

Hi Shachar,

Thank you for explaining very clearly.

Not aware FCC requiring a calibration process in the manufacturing to control the variation.

Usually, when the pass margin is good, the customer need not care about the part to part variation. However if the margin is small, it is recommended to check output power level in the production line is less than that of the ample certified for FCC. A 6 dB margin in emissions is usually good and 3 dB margin is not bad. Anything less than that is a risk.

However in most cases where the trace length is small and the tuning components have good tolerance, the variation is unlikely to be big enough to be concerned about.

Thanks

Ganesh

Great, thanks - I will pay attention to the points you highlighted.

0 Likes