Life time of nRF52810

RE: Life time of nRF52810

buja — Fri, 11 Mar 2022 14:48:48 GMT

Thank you

RE: Life time of nRF52810

Elfving — Fri, 11 Mar 2022 14:39:24 GMT

FIT refers "Failure In Time": a unit that represents failure rates and how many failures occur every 10⁹ hours. You can read more about this here.

HTOL refers to: High-temperature operating life, a reliability test applied to integrated circuits to determine their intrinsic reliability. This test stresses the IC at an elevated temperature, high voltage and dynamic operation for a predefined period of time.

60% CL refers to a Confidence Level of 60%

Regards,

Elfving

RE: Life time of nRF52810

buja — Fri, 11 Mar 2022 13:55:48 GMT

Thank you for your reply.

Could you please explain me what does this mean ?

[quote userid="103347" url="~/f/nordic-q-a/85572/life-time-of-nrf52810/357678#357678"]this is HTOL, PASS FIT (60% CL) : 51[/quote]

Also, what does FIT stands for ?

RE: Life time of nRF52810

Elfving — Fri, 11 Mar 2022 13:36:10 GMT

Hi,

The easy answer is that it will last for several years.

What is often mentioned in these contexts is FIT, which can be used to calculate a statistical MTTF (Mean Time To Failure). For the nRF52810 QFAA-B00, this is HTOL, PASS FIT (60% CL) : 51. When calculating the MTTF you should also take into account the amount of samples you have.

Flash (and potentially the battery, if applicable) is what most likely would stop functioning correctly first, and how long this would take depends on your use. The Flash is specified to last at least 10.000 Erase cycles, but can last much longer. Maybe your chip will last 50.000 cycles, it varies from chip to chip. If you are not planning on writing anything to the flash, there are also other issues related to its use, eg. data retention: how long the Flash can retain its state in various temperatures. We do not have any specific guaranteed numbers for room temperature on this, but it will likely last at least 10 years in 85 °C.

So in order for you to calculate how long your product would last, you would have to take into account how you are planning on using it. Here is an example of someone doing this, if it helps. And if the specs of the internal flash doesn't match what you would need you can always get external flash with the specs you would want.

Regards,

Elfving

RE: Life time of nRF52810

buja — Thu, 10 Mar 2022 11:34:57 GMT

Okay

RE: Life time of nRF52810

Elfving — Wed, 09 Mar 2022 15:03:04 GMT

Hello,

I will have to get back to you on this.

Regards,

Elfving