PDRUNEN@AOL.COM wrote:
> I been using some EPROM "windowed" 16C73 chips.  I am finding that over
> several cycles of erasing/programming (about 20) that the time to UV erase is
> becoming longer and longer.  I have a few that will not erase at all.
You too? Glad to see I'm not the only one with this problem.

I have a UV eraser with a timer and I've had to go from 2 minutes
for the first erases up to 20 now (after about 40 cycles).

What is wrong with MicroChip's EPROM technology that it takes
longer to erase as the cycle count rises? I see nothing in their
spec sheet on EPROM life but this effect is absurd.

The 16F87z series has a spec of 1000 cycles for the FLASH, so
beware that you can't cycle it forever.

> Any suggestion?

Microchip doesn't know how to make EPROM?

One could try baking the device at a high temperature (100C)
for a hour or so to dissipate the trapped ions (worked for
old 1702 EPROMs).