Something missed here in the comments is that this nvRAM is not EEPROM nor is it Flash. It would be very difficult to make a device that copies all its contents to Flash or EEPROM during the brief power-down period.
The Cypress device uses something called SONOS (look up SONOS memory in Wikipedia). As mentioned above, Everspin's similar devices use MRAM.
It is actually exciting to see these alternative non-volatile memories make it into the marketplace.
Understood, the article also clarifies store vs. write cycles. But if power down is so infrequent, the non-volatile benefit is diminished. You have to weigh is it worth to integrate the flash with the SRAM or just keep them separate since then the flash would be cheap commodity.
Older batteries sometimes appear so much better (in terms of longevity); wonder if QC is much better back then or else it has just slacked because most battery-powered product cycles are a few years now.
I am using BBSram and can go 10 yrs without replacing batteries and the battery replacement is online and no disruption of PLC operation. We have units that have been in the field for over 25 years. How do you replace the nvSRAM without a disruption before 20 years are up ?
nvSRAM runs as an SRAM in application, which has infinite endurance. You only use an endurance cycle when there is a power cycle... once a day... once a week. So the nvSRAM has effectively infinite endurance when used as defined.
This is a nice article at least for starters to think about nvSRAM applications. But it should mention that nvSRAM is basically SRAM backed up by Flash or EEPROM, so that is why it still has limited (~million) cycles.
@Ran de Silva, I agree that eventually MRAM might take the place of the non-volatile SRAM. But since MRAM is relatively a fresh technology I don't have much idea about the reliability of MRAM. Do you have any idea about the reliability of MRAM? What is the FIT (Failure In Million Hours) of the MRAM devices available from Everspin? Are they being used in such applications (if so I would be interested to know some data about the device ours of these devices in the field)
Nice article! But what could be the highest memory size of an nvSRAM available in the market? I am not sure if they are available with greater than 8Mbit memory size...are they? Also, compared to the battery-backed SDRAMs, won't the nvSRAM be very costly? How do you compare nvSRAM with battery-backed SDRAM?
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