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ID-ing RAM Chips (Datasheet?)

Terry Yager

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Joined
May 1, 2003
Messages
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Location
Saginaw, MI, USA 48601
Can anyone help identify these chips, or point me to a datasheet?

AA1M200P-08H
NMBS 8939

They're 18-pin ceramic DIPs, but I can't find any info. Are they 4-bit x 256Kb, 1-bit x 1Mb, sum'n else, or what?

--T
 
I searched through a multitude of online databases. Only one listed that type of chip, but referred to a PDF on another site which declined that a such document existed. All the others at best refer to a Zener diode with a similar part number. Maybe someone else has better luck than me, or knows what to search for. I suppose NMBS indicates who manufactured it?
 
MeToo. I searched all the datasheet archives I know of, no joy. I believe that 18 of 'em add up to 2Mb + parity. The 8 x 1Mb chips I'm used to seeing are 20-pin packages. I also found an AA1M204P-08, which is a 4 x 256Kb, 18-pin, and an AA1M100, which is a 1 x 1Mb, 20-pin, so the ones I have must be in the same family.

Any idea what the NMBS means? Some of the other chips are so designated too.

--T
 
Last edited:
there is another one, AAA LM200P

if you do a google, it comes up with a 1MB dram (but you already know that!), probably an editorial ad from the ieee magazine in 1990 (agrees with date code of end of 1989), but it requires subscription. the z and J suffixes don't help either.
 
NMBS changed to NPNX

NMBS changed to NPNX

try www.digchip.com Couldn't match the AA number but NMBS 8939 does have a listing (not much info)
Several mentions about this company in the IBM archive
 
From one of my many data books:

AAA1M200P08H

Manufacturer = NMB Semiconductors
Technology = CMOS
Config = 1M x 1 bit
Access Time = 80nS
Write Cycle Time = 150nS
Output Type = 3 state
Vcc = 5 V
Package = DIP
Operating Temp Range = 0-70 degrees C

PINOUT
-------
1 = Din (data in)
2 = WE (write enable - active low)
3 = RAS (row address strobe - active low)
4 = NC (not connected)
5 = A0
6 = A1
7 = A2
8 = A3
9 = Vcc (+5V)
10 = A4
11 = A5
12 = A6
13 = A7
14 = A8
15 = A9
16 = CAS (column address strobe - active low)
17 = Dout (data out)
18 = Vss (ground)
 
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