Wanted: ASM-48 for Intellec MDS-2

Eric Smith spacewar at gmail.com
Tue May 19 22:09:35 CDT 2015

On Tue, May 19, 2015 at 6:20 PM, Richard B. Main, Esq.
<mainpatents at gmail.com> wrote:
> That just sounds wrong to me applying +25v to do a read/verify.  You're
> misinterpreting the datasheets. Richard

It may "sound wrong", but that's actually the *only* way to read the
EPROM 8741, 8741A, 8748, and 8749. If you don't apply high voltage to
the EA pin, it doesn't go into verify mode.  It's fully documented in
the data sheet, and I've verified that commercial programmers do that.
It's possible that verification will work at somewhat less than 25V,
but it definitely does NOT work at under 6V.

The issue is that the 8041, 8041A, 8048, and 8049 masked-ROM parts are
not rated for 25V on EA.  The 8748 and 8749 datasheets say to use 12V
on EA.  The 8041 and 8041A datasheets don't say, but since it's almost
the same design and definitely the same fab process as the 8048, I'm
pretty sure that they need 12V also.

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