is CY62256NLL drop-in replacement for AS6C62256?

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mightydidz
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Joined: Wed Jan 24, 2018 12:04 pm

is CY62256NLL drop-in replacement for AS6C62256?

Post by mightydidz » Sat Oct 17, 2020 5:29 am

I was previously using for couple of my pcb, but now my supplier is having issue finding the Alliance SRAM
I'm using sTSOP-28 package

https://www.digikey.ca/en/products/deta ... IN/4499003


I was wondering if the Cypress would be a direct fit replacement?
https://www.digikey.ca/en/products/deta ... IT/1205295

Looking at the datasheet, only the addresses are labelled differently, so I don't think it need circuit modification?
ISB1 are similar, VDR is 2.0v instead of 1.5V for Alliance, would this make a big difference for data retention?

Or do you guys have any other suggestions or favorite 32K RAM?
Thanks

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Ben Boldt
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Joined: Tue Mar 22, 2016 8:27 pm
Location: Minnesota, USA

Re: is CY62256NLL drop-in replacement for AS6C62256?

Post by Ben Boldt » Sat Oct 17, 2020 12:07 pm

It shouldn't make any difference what order you connect address lines on an SRAM, so I think you are OK there. Just recently I mentioned something to this nature and aquasnake had replied that the highest order address bits might be slower. I couldn't make any sense of it but maybe he know something we don't... That post is here: viewtopic.php?p=256826#p256826

The higher V(DR) would mean that your lithium battery doesn't have to get as low before you lose the SRAM data/save game. However, I(DR) is a lot lower so I suspect that your battery ends up lasting longer overall because of that. I don't think it's a concern either way -- it might be a toss-up whether the SRAM battery or your flash data retention goes first anyway.

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