Also have a look at the Maxim 1210. It can use two backup batteries along with the main supply. You route the RAM chip select and Vcc through the 1210 so it disables the RAM when power is lost and powers the RAM. I used a 1F capacitor to back up a 128kbyte RAM. Watch the maximum backup voltage spec. If you put too high a voltage on there, the chip won't pass through any chip selects (discovered through experience).
Harold
---------- John Hansen <.....hansenKILLspam
.....FREDONIA.EDU> writes:
Dallas Semiconductor (now Maxim) still makes them and they are sold by JDR
(http://www.jdr.com). Do a search on SRAM at JDR and you'll find them. They also
have battery back sockets that you can stick any old SRAM in.
John Hansen
At 09:42 PM 1/15/03 +0100, Fredrik Axtelius wrote:
{Quote hidden}>Is there anyone that still makes small battery backedup SRAM chips??
>I looked around but couldnt find any, anyone have any ideas?
>32K is enough, 8 databits.
>
>Or, is this something I easily can build myself?
>I heard something about a battery and a zener, would that work?
>
>tia
>/Fredrik
>
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