9 Jul
2007
9 Jul
'07
8:15 p.m.
I recently came across a stock of what seems to be 16 bit wide memory chips.
But I'm getting nowhere trying to find a data sheet. Can anybody help out?
The parts are UM61M512K-15, 32 pins DIP. The logo is round, world shaped
with 3 vertical and 3 horizontal lines. Date codes are 95 and 96.
The parts were on some mini-486 PCBs.
If these really are 16 bit wide and 32K deep, they would be great for a SBC
I'm building. Especially if the 15 means 15 ns.
Any help for pinouts or data sheet greatly appreciated.
Billy
9 Jul
9 Jul
8:50 p.m.
--- Billy Pettit <Billy.Pettit at wdc.com> wrote:
The parts were on some mini-486 PCBs.
These are undoubtedly high-speed CMOS cache RAM.
There were many makers of these in the 486 era,
and the pinouts tended to be standard. Do you
have a manual for the 486 boards? It will likely
specify compatible cache chips, as these were
freqently supplied by the integrator, not
pre-installed.
If these really are 16 bit wide and 32K deep, they
would be great for a SBC
I'm building. Especially if the 15 means 15 ns.
I found a datasheet for a UM61512AK-15 (at
www.alldatasheet.com) which is a
15ns 64K x 8 CMOS SRAM. I suspect it is similar.
--Bill
9:27 p.m.
On 9 Jul 2007 at 17:50, William Maddox wrote:
And the ISSI IS61M512-15N is a 64Kx8 15 nsec. SRAM. So, most likely
it isn't a 16-bit wide version.
OTOH, there's a nice 16bit SRAM in some modems, such as the Hayes
28.8K external models. In an 0.300" wide DIP too.
Cheers,
Chuck
I found a
datasheet for a UM61512AK-15 (at
www.alldatasheet.com) which is a
15ns 64K x 8 CMOS SRAM. I suspect it is similar. 
10 Jul
10 Jul
4:08 p.m.
On 7/9/07, Chuck Guzis <cclist at sydex.com> wrote:
OTOH, there's a nice 16bit SRAM in some modems,
such as the Hayes
28.8K external models. In an 0.300" wide DIP too.
Oooh... that could be fun to play with. I didn't figure that a cache
SRAM was anything other than 4-bits wide (386/486 era) or 8-bits wide
(486/Pentium era), especially since I've used a bog standard cache RAM
on an 1802, but knowing there really are 16-bit-wide SRAMs could be
fun for, say, a 68000-based board, or even throwing away 4 bits and
using it as a 12-bit-wide single part for a PDP-8.
Any idea what the part number might be for that RAM chip? Vendor?
-ethan
7:03 p.m.
On 10 Jul 2007 at 15:08, Ethan Dicks wrote:
On 7/9/07, Chuck Guzis <cclist at sydex.com>
wrote:
There are lots of 16-bit SRAMs, but (my mistake) not in a DIP style.
The Alliance AS7C1026 for instance gives you 64Kx16 bits in a 44 pin
TSOP SOJ--as fast as 10 nsec.
The DIPs seem to be restricted to 8 bit wide memories, such as the
Alliance AS7C1024 (128Kx8 in 32 pins 0.300 SOJ DIP found in the Zoom
56K modem). Just too many pins, I guess when the width goes to 16.
But why stop with 64Kx16 SRAM? There's the Maxwell 89C1632
512Kx32bit SRAM in a 68 pin QFP...
Cheers,
Chuck
OTOH, there's a nice 16bit SRAM in some
modems, such as the Hayes
28.8K external models. In an 0.300" wide DIP too.
Oooh... that could be fun to play with. I didn't figure that a cache
SRAM was anything other than 4-bits wide (386/486 era) or 8-bits wide
(486/Pentium era), especially since I've used a bog standard cache RAM
on an 1802, but knowing there really are 16-bit-wide SRAMs could be
fun for, say, a 68000-based board, or even throwing away 4 bits and
using it as a 12-bit-wide single part for a PDP-8. 
9 Jul
9 Jul
9:02 p.m.
Quoting Billy Pettit <Billy.Pettit at wdc.com>:
I recently came across a stock of what seems to be 16
bit wide memory
chips.
But I'm getting nowhere trying to find a data sheet. Can anybody help
out?
The parts are UM61M512K-15, 32 pins DIP. The logo is round, world
shaped
with 3 vertical and 3 horizontal lines. Date codes are 95 and 96.
The parts were on some mini-486 PCBs.
If these really are 16 bit wide and 32K deep, they would be great for a
SBC
I'm building. Especially if the 15 means 15 ns.
Sounds like Sram from the L2 Cache on the 486 boards.
10 Jul
10 Jul
6:02 a.m.
I recently came across a stock of what seems to be 16
bit wide memory
chips.
But I'm getting nowhere trying to find a data sheet. Can anybody help out?
The parts are UM61M512K-15, 32 pins DIP. The logo is round, world shaped
with 3 vertical and 3 horizontal lines. Date codes are 95 and 96.
The parts were on some mini-486 PCBs.
If these really are 16 bit wide and 32K deep, they would be great for a SBC
I'm building. Especially if the 15 means 15 ns.
Any help for pinouts or data sheet greatly appreciated.
I have it here, check your mailbox :o) But these are 8-bit 64K SRAMs,
not 16 bit. Very useful for eprom emulators and small old computers ;o)
1:32 p.m.
On Monday 09 July 2007 20:15, Billy Pettit wrote:
I recently came across a stock of what seems to be 16
bit wide memory
chips. But I'm getting nowhere trying to find a data sheet. Can anybody
help out?
The parts are UM61M512K-15, 32 pins DIP. The logo is round, world shaped
with 3 vertical and 3 horizontal lines. Date codes are 95 and 96.
Perhaps this might help for the logo:
http://www.classiccmp.org/rtellason/logos/semiconductorlogos.html
?
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
2:04 p.m.
On 10 Jul 2007 at 13:32, Roy J. Tellason wrote:
Perhaps this might help for the logo:
http://www.classiccmp.org/rtellason/logos/semiconductorlogos.html
Actually, the part number is the giveaway--UMC is the manufacturer.
(UMxxxxx)
Cheers,
Chuck
3:44 p.m.
I recently came across a stock of what seems to be 16 bit wide memory =
chips.
But I'm getting nowhere trying to find a data sheet. Can anybody help =
out?
=20
The parts are UM61M512K-15, 32 pins DIP. The logo is round, world =
I doubt they're 16 bits wide. The '512' in the part number would suggest
512KBits, or 32K 16 bit words.
Now, unless I am missing something, a 32K-location RAM would need 15
address lines. Along with 16 data lines, a write-enable, a chip select
line, power and ground. That's over 32 pins.
My guess is that they're 64K*8 bits.
Thw logo sounds like UMC, who made a lot of chips that ended up in PCs. I
have their microprocessor+peripherals databook from about 1990, but
nothing on their RAMs.
-tony
6226
days inactive
6227
days old
10 comments
8 participants
participants (8)
-
alexandre-listas＠e-secure.com.br -
ard＠p850ug1.demon.co.uk -
Billy.Pettit＠wdc.com -
cclist＠sydex.com -
ethan.dicks＠gmail.com -
geoffr＠zipcon.net -
rtellason＠verizon.net -
wmaddox＠pacbell.net