Serial SRAM for BS2e

edi

Hi All,
I need a Serially interfaced SRAM.
Other requirements :
1 - 4K X 8· size
2 - I2C or SPI, etc. type of interface
3- Volatile SRAM· (I do not want Non-Volatle SRAM)
4- PDIP package (something small 8 pins or so)

Please provide vendor & part number.

Thanks

PJAllen

· OK, I posted these links, and then RE-read yours, and you state VOLATILE SRAM.· Whatever for?· (Well, obviously: you don't want to retain data when you turn it off.)

· I've never seen an 8pin SRAM (I2C or otherwise.)· There are still SRAMs (parallel) out there and they could be interfaced with a serial-in to parallel-out shift register/s.

http://www.parallax.com/detail.asp?product_id=604-00020

http://www.parallax.com/detail.asp?product_id=602-00008


Post Edited (PJ Allen) : 10/12/2005 8:04:05 PM GMT

Paul Baker

Well, all serial SRAM chips that I know of are discontinued and no longer availible, (Dallas/Maxim used to make them but do not anymore). Why is criteria #3 so important? Is there anyway you can detect a start up condition and bulk erase the chip, or just ignore the previously written data?

PJ, those are EEPROMs and therefore non-volatile (ok you've edited your post )

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Post Edited (Paul Baker) : 10/12/2005 8:05:34 PM GMT

edi

Hi All,
One additional requirement :
5 - Unlimited write cycles (this precludes EEPROM usage)
Thanks

PS's :
PJ : thanks for the response but I cannot use EEPROMS
Paul : #3 is important because of cost. Battery in NVSRAM will raise costs.
·

Paul Baker

Have you looked at FRAM? Just like EEPROMS but faster and rewrittability in the trillions (docs state that continual use of 32 bytes in a circular fashion at max bus speed will take 15 years for that block to be exhausted).

www.ramtron.comdoc/Products/serial.asp

There unfortunatley isnt a 4kx8 size (8kx8 is availible). Also another issue is they have discontinued the PDIP package, for prototyping purposes you can get a breakout board for 8-SOIC (like at www.sparkfun.com), then for production it will be cheaper in PCB real-estate because it takes up less space.

www.newarkinone.com sells 8kx8 SPI and I2C types for just over $3 apeice.

The parts you would be interested in are FM25640·for SPI and FM24C64·for I2C

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Post Edited (Paul Baker) : 10/12/2005 10:48:37 PM GMT

edi

Hi Gentlemen,

Thank you all for taking the time to post.

Mr. Baker - thanks for the FRAM recommendations + links. I will use this device for my project.

Regards,

Richard