7 Mar
2014
7 Mar
'14
5:50 a.m.
The other alternative is the Simtek STK16C88 quantum
trap SRAM (now also
Cypress). This device has unlimited reads and writes but has 1e6
power-down cycle endurance. 100 year data retention.
This device is also pin compatible with the SRAMS and is 5v. It may be
a better choice than the FRAM.
http://www.cypress.com/?docID=34462
They are also available on EBAY for about $10.00.
Rob.
--- Thank you for the suggestion but that option was discussed in the article. Quoting:
I also looked at the 32Kx8 Cypress STK16C88 flash-type NVRAM, which costs $13 at Mouser.
It?s being phased out and the replacement is neither 5V nor through-hole. Nevertheless,
since the STK16C88 is still in production, I considered using it. After all, the prospect
of getting rid of the battery altogether is very attractive. Unfortunately, I could not
find any ESD specs in either the commercial or military versions of the datasheet. This,
along with the fact that it is being discontinued and has some spooky
voltage/timing/retention requirements, discouraged me from using the part. Not to mention
that the two required would cost $26, versus the $4 we would have paid for a pair of
CY7199s.
Steve Lafferty