29 Jul
2004
29 Jul
'04
1:13 p.m.
>I have a couple of "ultraviolet" LEDs
with me, but I doubt they are the
>right frequency to erase EPROMs.
If they're the high power UV LEDs then they should
work. A friend of
mine uses those to erase his EPROMs and the erase time is about the same
as for a UV light.
There are not yet available UV LEDs that radiate at short enough wavelength
to erase EPROMs in a reasonable time. Most EPROMs will start to erase at
<400nm but take hours of exposure, to erase an EPROM in 20 mins or so needs
12mW/cm^2 of 257nm light on the die face. The longer wavelengths just warm
the chip up a bit.
This is why UV tubes for photo resist and similar won't erase EPROMs either,
they output nearer 400nm which is where state of the art UV LEDs are at.
Lee.
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