PROM / EPROM chips large than 2 Mb?

Last I heard, there is bubble memory as large as 4 MB

Bubble memory is non-volitile, writes at 15 V reads at 5V

Any links to possible sources?

http://www.newstarget.com/019614.html

http://www.freescale.com/

The second link seem very useful. Thanks.

I think there is a Motorola company in Israel. It might be easier to go through them

There is, but it's an R&D center, not sales outlet. Just like Intel and Microsoft. They design there, not sell. For sales there are local distributors.

I thought I would find it with a focused web search, but couldn't find any.

Someone had a cool idea to design, and said current chips are too small for his idea to be effective, and been at the same volume for some ten years, as if this venue of PROMS has been neglected in favour of Flash (ferro-magnetic) chips, which although today are available in volumes of 8 Gb by Samsung, Sandisk (featured article links), and others, only that Flash is not suitable for his application because they are erasable once written as any EEPROM.

He is more inclined for the recent Fuse-Burn technology which is very fast to read and immune to erasure, once written.

That is the cheapest route. If the current chips are too small, why not use more than one? The only difference would be an address line used to select which chip is used.

I guess you are right, provided he finds some hard-wired omission to the possibility of erasure.

In the old days (maybe even today, I can't really tell), System-ROMs were matrix-etched with a technology which is the safest from erasure, even with chip-blowing EMP, which was then called Mask-ROM, meaning the software-segments were litho-etched to the chip lattice, then encapsulated in ceramics

http://www.st.com/stonline/stappl/productcatalog/app?path=/comp/stcom/PcStComOnLineQuery.showresult&querytype=view=table$$type=product$$Parametric=N&querycriteria=RNP139=584

I think they've got mixed up between Megabits and Megabytes in their size column.

Did you want larger than 2 megabits (Mb) or Megabytes (MB)

Megabits. Divided into 24 bit words plus 7 mode bits and one negation bit, it leaves very little for useful storage.

The Flash sources usually quote their models with Megabytes, since they target their products to store large-volume multimedia files.

http://www.freescale.com/webapp/sps/site/overview.jsp?nodeId=015424

This page has the data sheet for MR2A16A at 4 Mb organized in 16 bit words Software commands can easily make double words to get your 24 + 7 + 1= 32

It also has a link to order a sample

Thanks. The MR2A16A looks like a possible candidate, although it's not mine to decide.

It's high rate (35ns) access is exactly what's on stake there, and the (20 years) MTBF is very promising for the project in mind.

It also has an automatic low-voltage crash prevention, although the chip is meant to be written only once, with a data verification routine to follow.

It is still low on volume compared to similar Flash devices as the inventor hoped for, but on all other accounts, I think it's very suitable.

I guess it will mean larger or multiple boards design.

One has to do their best with what's available, I guess.