[vcf-midatlantic] Good source for eproms?

Herb Johnson hjohnson at retrotechnology.info
Fri May 27 11:02:15 EDT 2016

My comments and questions.

Dave McGuire posted:
>   They can be erased with X-rays.  EPROMs were originally designed to be
> erased that way.  There are problems with that approach, however. (hence
> the move to UV).

The notion that one can plop non-quartz PROMs under an X-ray and erase 
them, has been mentioned here, and elsewhere for decades,  as a "could 
be done". But I'm not aware this has been, or is, any sort of common 
practice, much less an established procedure. I'm aware of 'theory', I 
know physics. I'm talking accepted practice.

Wikipedia....EPROM...citation 6...is a May 10 1971 article from 
Electonics Magazine by Dov Frohman, who apparently "invented the EPROM". 


references the article, and interviews the author later in 1993. The 
text say Intel shipped that 1702 EPROM "with a window because X-rays 
....disrupted the structure" of the chip. The Web page has some details. 
I"ve not (yet) read the article, or checked the patent.

This suggests that X-rays were not a production nor a customer practice.

so: Can you cite a reference I can find also, that shows a product 
announcement, or a production data sheet, that says specifically that a 
customer can erase a specific PROM product using X-rays of a particular 
wavelength and energy for a particular period of time?  That's how UV 
exposure is cited (when it was cited in detail) in data sheets.

I'll grant the possibility this occurred for some very early product, 
some early development in the semiconductor lab, or some military or 
other specialized application. I'll grant some hackers could borrow a 
dental X-ray and erase an EPROM - did they do subsequent life-tests? 
Even that description would be of interest. Thank you.

Herb Johnson

Herbert R. Johnson,  New Jersey USA
http://www.retrotechnology.com OR .net

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