how do I read what's printed on sram chips?

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sevast
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how do I read what's printed on sram chips?

Post by sevast » Thu Aug 17, 2006 8:12 pm

How do I read the information printed on the outside of sram chips to get their size? I tried googling what's on the chips and also search a couple component stores for sizes but I didn't have much luck...

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kyuusaku
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Post by kyuusaku » Thu Aug 17, 2006 8:59 pm

6264 is the generic name for 8Kbit x 8
6216 is 2kib
62128 is 16kib
62256 is 32kib
62512 is 64kib
628128 is 1m
628256 is 2m
628512 is... 4m

8M SRAM aren't terribly common but do exist as do 16 and 32M, the names of 8M plus aren't standardized and often aren't available in DIP packages. After 8M you're talking $20+ an IC in hobby quantities.


<something>65 is probably 64kbit as well

<something>LP = low power

<something>-12 = 120ns
<something>-20 = almost certainly 200ns
<something>-10 = either 100ns or 10ns (only really expensive recent SRAM are 10ns)
<something>-7 = 70ns
<something>-70 = 70ns


If you can't remember just go to datasheetarchive.com

sevast
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Post by sevast » Fri Aug 18, 2006 12:00 am

I guess I'm kinda screwed if it's not at that site?

I've got this on a nes related circuitboard:

LH51168FB-10TL
LSMLOGIC JAPAN
D223 #HBG

I've got this on a DQV J:

Sanyo
LC3564QL-10N
JAPAN 25075


I know I can look up the DQV (I would guess 64), but I was really hoping to be able to figure out the other one. I was also hoping that there was some simple method of knowing like how eproms are marked... :)

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kyuusaku
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Post by kyuusaku » Fri Aug 18, 2006 8:08 am

The Sharp is a standard 6116 (2k)

The Sanyo is a standard 6264 (8k)

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blargg
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Post by blargg » Fri Aug 18, 2006 10:14 am

The number of pins on the chip package also give an indication of the maximum size it could be. There are usually 8 pins for data, two for power, one or two for chip select, one for read/write differentiation, and the rest could be for address selection.

sevast
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Post by sevast » Fri Aug 18, 2006 12:00 pm

Ok, kyuusaku, please tell me how you found those out? I may just not be dense, but I want to learn how to look that up! I tried the website that you posted, but I couldn't find either.

I don't want to be one of those guys who just asks crap randomly because they never took the time to know anything. I actually want to learn! :)

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kyuusaku
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Post by kyuusaku » Fri Aug 18, 2006 12:11 pm

Generally it's:

*16* = 16kbit = 2k = 6116
*64* = 64kbit = 8k = 6246

LH = Sharp, instead of 61/62 they use 51

Maybe Sanyo uses 35 instead of 62, dunno

You just remember this stuff when you spend a lot of time tinkering.
When you enter the part number in a search engine, remove the stuff after the ROM size, most people omit that so it will restrict your matches

(instead of LH51168FB-10TL, search LH51168) generally you won't even care about the stuff after the ROM size. In this case, Sharp tacked on an extra 8 (to point out the obvious 16x8) on the product code so that complicated things a little but remove it and you get the generic Sharp part which is LH5116 (6116)

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