[sdiy] Substituing M48Z18-100 (equ of DS1225AB-100) with 28 pins DIP small pcb

Jason Tribbeck jason at tribbeck.com
Sun Apr 25 19:00:02 CEST 2021


DS1225 does seem to still be available from Farnell:
https://uk.farnell.com/maxim-integrated-products/ds1225ab-70ind/nv-sram-parallel-64kbit-edip-28/dp/2798716

Or you could look at FRAM, for example Cypress FM16W08-SG :
https://uk.farnell.com/cypress-semiconductor/fm16w08-sg/f-ram-non-vol-64kbit-soic-28/dp/2772905

I'm pretty sure FRAM can be used in the same way as SRAM.

On Sun, 25 Apr 2021 at 16:02, Jean-Pierre Desrochers <jpdesroc at oricom.ca>
wrote:

> Hi list,
>
> I need to replace a M48Z18-100PCI (8K x 8 battery backed SRAM) in one of
> my old
> test equipment. It's dated 1996 so It's inner battery life is ending.
>
> Yeah even after 25 years it still keeps its data.. (!!!)
>
> It's a 28 pins 600mil DIP package.
>
>
>
> The specs say it is full Dallas DS1225 compatible.
>
> There are many sites who show how to hack a DS1225 package
> to disconnect the inner battery tabs and connect small leads
> to an external battery keeping the still working SRAM.
>
> This for example:
>
>
> https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwiDl_DKzZnwAhVdElkFHZaBCTsQFjABegQIAhAD&url=http%3A%2F%2Fworldphaco.com%2Fuploads%2FTEKTRONIX_2465b_OSCILLOSCOPE_CALIBRATION___REPOWERING_THE_DS1225.pdf&usg=AOvVaw1WP8nMcsFuEALX2uMw2rP1
>
>
> Since my chip is a M48Z18-100PCI it does not have the same
> potted packing of a genuine DS1225 (should it ??) so dremeling it
> to reach the battery tabs would be quite hazardous..
>
>
>
> *So here is my question:*
>
> I'd like to build a small 28 pins 600mils DIP pcb
> who would contain a 8Kx8 SRAM with battery controller IC
> the same way the inside DS1225 does it:
>
> DS1218 and DS2064 are now obsolete ICs so this would not be a good choice..
>
>
>
> A company called Glitch Works has this type of new substitute IC available:
>
>
> https://www.tindie.com/products/glitchwrks/glitch-works-gw-1225-1-dallas-ds1225-replacement/
>
> But for me $51.00US including shipping to Canada is too expensive..
>
> But the idea of a small 28 pins DIP pcb module is a good one..
> Building it would be fun too !
>
> I’m not an engineer and cannot figure out the DS1225 read/write needs to
> be taken care of
> choosing the right components. Any 8Kx8 SRAM with a 100ns acquisition
> should do
> but the choice of a good battery controller IC and the adequate
> connections between both IC’s
> and the 28 DIP pins to behave exactly like a M48Z18 or DS1225 exceeds my
> knowledge..
>
> Can you help with some possible IC’s and some easy wirings linking them ?
>
> Many thanks !
>
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>


-- 
Confucius says: Man with problem who thinks solution is regular expression
now has two problems.

*/s/two/many/*
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20210425/1071acd7/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image003.png
Type: image/png
Size: 116678 bytes
Desc: not available
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20210425/1071acd7/attachment.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image002.jpg
Type: image/jpeg
Size: 30811 bytes
Desc: not available
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20210425/1071acd7/attachment.jpg>


More information about the Synth-diy mailing list