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# Non Volatile RAM (F-RAM & NVSRAM)

New Contributor

## Endurance of F-RAM in CY15B108QN-40

Hello,

The downloaded document from https://www.cypress.com/file/444186/download,shows on Pg 17, it's endurance limit of 432 yrs, operating at SCK freq of 40Mhz. These calculations r based on reading 64 byte data sequentially.

If I do random Fast-Read continuously then based on the same calculations the endurance cycles/sec comes to 800,000 (this includes CS disable time of 50nSec) and the yrs to reach this limit falls to ~40

I want to know if I am on the right track or there's something more to it?

Thanks,

Regards,

Sailesh..

1 Solution
Moderator

## Re: Endurance of F-RAM in CY15B108QN-40

Hi Sailesh,

We have a KBA on Endurance limit calculation. I am adding the link below for reference.

I am not able to follow your calculations for fast read opcode. Can you provide us more details on them for us to better understand them.

https://community.cypress.com/t5/Knowledge-Base-Articles/Calculation-of-Endurance-Limit-for-FRAM-Dev...

Thanks,

3 Replies
Moderator

## Re: Endurance of F-RAM in CY15B108QN-40

Hi Sailesh,

We have a KBA on Endurance limit calculation. I am adding the link below for reference.

I am not able to follow your calculations for fast read opcode. Can you provide us more details on them for us to better understand them.

https://community.cypress.com/t5/Knowledge-Base-Articles/Calculation-of-Endurance-Limit-for-FRAM-Dev...

Thanks,

New Contributor

## Re: Endurance of F-RAM in CY15B108QN-40

let's presume I am reading randomly, I have Instruction(8b)+Address(24b)+Dummy(8b)+Data(8b) = 48bits. Operating SCK at 40 Mhz will mean 1.2uSec have elapsed. If I add 50nSec to terminate this and start another random address reading it'll mean I have repetition 1/1.25uSec or 800,000 cycles/sec.

The internal architecture will still access 64bytes, read and write back at 1.25uSec rate.

800,000 cycles/sec comes to 25.2 x10^12 cycles/year.  Hence to reach endurance of 1x10^15 it will take  39.64 years.

Thanks,

Regards,

Sailesh..

Moderator