Old IC RAM Identification? - test-drb@ccmp.vtda.org

11 Mar 1999

On Mar 11,  7:56, Rick Bensene wrote:
...
  Subject: Old IC RAM Identification?
 Anyone out there that can identify (i.e. size & arrangement(IE: 1Kx1)
 and technology (i.e. Dynamic vs Static)) of some old RAM IC's?

 The parts are made by National, circa 1973.  Part numbers are:

 MM4260 and MM5260 
I've never seen any and those numbers aren't in my copy of Towers, but the
nearest are

MM4250, DIL 16, 256 x 1 SRAM, 650ns, 8 addr lines, 1 CS line, PMOS, +5V,
-9V, 37mA, TTL output levels.

There's an MM4261 listed, it's a 1024 x 1 DRAM with two more address lines
and two more CS lines in an 18-pin DIL package, and an 4262 is 2048 x 1, so
I'd guess your MM4260 is similar to a 4250 (256 x1).  Sorry, no pinout.

There's no 5250 or 5260 listed but there are MM5261 and MM5262.  They look
very similar to the 42xx but slightly faster, and they use +5, +6.5, and
-12V.

...
  These are found on an old memory board that is
organized in four groups
 of 5 chips, with 3 4260's and 2 5260's in each group of 5. 

-- 

Pete						Peter Turnbull
						Dept. of Computer Science
						University of York