On Fri, Jul 30, 2004 at 02:13:47AM +0100, Davison, Lee
wrote:
>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.
I will have to check, but IIRC, my LEDs are 450nm.
I just called and talked to my friend about this. He has some >>
prototype << high power UV LEDs that are about 375nm. He also some that are
deeper UV but the phone connection was lousy and I couldn't get any more
details. I'm not even sure which ones he used to erase the EPROMs with or
how long it took. Your 450nm LEDs probably won't work.
Joe