EEPROM ID 27HC641

[KC-Pins]

I bought a large lot of misc EPROM's, and have a handful that are not in my
ROMMAX programming software, and in experimenting, I can't figure out what
size they are. They are 24 pin like a 2716/2532/ etc as opposed to the 28
pin 27C64 chips I'm used to, so I'm a bit confused. They have an S on the
chip, I think it's Signetics? Does anyone know how I can use these?

 

[Mark (UK)]

Hiya!

The Data I/O 29B can do them (FamPin 090/067), and according to the
pinout list, they are equivalent to AM27S49*, which is an 8912x8 BiPolar
PROM.

Are they in plastic package, or ceramic with a window? If plastic, they
are likely to be one time programmable.

Cypress still do some of the larger type of BiPolar PROMs in ceramic
with windows so they can be erased (ex. CY7C281 = 82s181), TI used to do
the 27c291 (82s191) but have now discontinued it. Unfortunately they
don't do the smaller ones like the 82s129 that we arcadies use :-(

Yours, Mark.

*And also:
MMI63S6481
MB7143/4
Harris 76641
.....amongst others

KC-Pins wrote:

I bought a large lot of misc EPROM's, and have a handful that are not in my
ROMMAX programming software, and in experimenting, I can't figure out what
size they are. They are 24 pin like a 2716/2532/ etc as opposed to the 28
pin 27C64 chips I'm used to, so I'm a bit confused. They have an S on the
chip, I think it's Signetics? Does anyone know how I can use these?