Post by thread:JW Erase Time

Hi, I bought a few JW devices (x54,x56,x57) about two years ago. These devices erased in about 4 minutes under my eraser. Recently I bought another x57 and this chip takes 12+ minutes to erase under the same lamp! Is the part suspect or have Microchip made their devices a bit harder to erase in the last two years? Niki spam_OUTsteenkmpTakeThisOuTfirga.sun.ac.za

It could be that the UV light output of the lamp has dropped. This is normal and it depends on how much you use the eraser. You see the same problem with solarium banks, you know those things people fry themselfs under to get a nice brown skin, they tend to get weak after a period of time. My girlfriend has a solarium and i used to lay my eproms next to her to have them erased by the UV light. works great !!!!! Greetings Eric Martens *************************** * Eric Martens * * .....emarKILLspam@spam@knoware.nl * ************************** ---------- | From: N STEENKAMP [M.ING E&E] <STEENKMPKILLspamFIRGA.SUN.AC.ZA> | To: .....PICLISTKILLspam.....MITVMA.MIT.EDU | Subject: JW Erase Time | Date: donderdag 29 mei 1997 18:32 | | Hi, | | I bought a few JW devices (x54,x56,x57) about two years ago. These | devices erased in about 4 minutes under my eraser. Recently I | bought another x57 and this chip takes 12+ minutes to erase under the | same lamp! Is the part suspect or have Microchip made their devices a | bit harder to erase in the last two years? | | Niki | EraseMEsteenkmpspam_OUTTakeThisOuTfirga.sun.ac.za

Are you sure it isn't the lamp? This is typical with use. You may want to see if your old parts still erase in 4 minutes! Chris ---------------------------------------------------------------------- Chris B. Sakkas (chrisspam_OUTitutech.com) http://www.itutech.com ITU Technologies (@spam@infoKILLspamitutech.com) ftp://itutech.com *** Upgrade your PICSTART programmer to program the latest devices *** *** with the PHOENIX firmware upgrade! See our web page for details! *** *** VISA and MasterCard accepted (513) 661-7523 ***

On Thu, 29 May 1997 14:14:10 +0000 Chris Sakkas <KILLspamchrisKILLspamitutech.com> writes: >Are you sure it isn't the lamp? This is typical with use. You may >want to see if your old parts still erase in 4 minutes! > Also, be sure to clean the chip window before erasing. Fingerprints and smudges of adhesive from old sticky labels may not look like much under visible light, but they can block UV quite well. -Mike

At 04:32 PM 5/29/97 GMT+0200, you wrote: >Hi, > >I bought a few JW devices (x54,x56,x57) about two years ago. These >devices erased in about 4 minutes under my eraser. Recently I >bought another x57 and this chip takes 12+ minutes to erase under the >same lamp! Is the part suspect or have Microchip made their devices a >bit harder to erase in the last two years? Look in the window and compare die sizes. Andy ====================================================================== Andy Kunz - Montana Design - 409 S 6th St - Phillipsburg, NJ 08865 USA Electronics for Industry & R/C Hobbyists "Go fast, turn right, and keep the wet side down!" ======================================================================

At 01:00 PM 5/29/97 -0400, you wrote: >At 04:32 PM 5/29/97 GMT+0200, you wrote: >>Hi, >> >>I bought a few JW devices (x54,x56,x57) about two years ago. These >>devices erased in about 4 minutes under my eraser. Recently I >>bought another x57 and this chip takes 12+ minutes to erase under the >>same lamp! Is the part suspect or have Microchip made their devices a >>bit harder to erase in the last two years? > >Look in the window and compare die sizes. >Andy Exactly! If the die is smaller, allow more erase time. Jim > >====================================================================== >Andy Kunz - Montana Design - 409 S 6th St - Phillipsburg, NJ 08865 USA > Electronics for Industry & R/C Hobbyists > "Go fast, turn right, and keep the wet side down!" >====================================================================== > >

> >>Hi, > >> > >>I bought a few JW devices (x54,x56,x57) about two years ago. These > >>devices erased in about 4 minutes under my eraser. Recently I > >>bought another x57 and this chip takes 12+ minutes to erase under the > >>same lamp! Is the part suspect or have Microchip made their devices a > >>bit harder to erase in the last two years? > > > >Look in the window and compare die sizes. > > >Andy > > Exactly! If the die is smaller, allow more erase time. > The die is actually smaller, but (this might be a stupid question) why would a smaller die take longer to erase? If the floating gates are smaller, then less charge will be on them and then it would take less time to remove it...? Niki RemoveMEsteenkmpTakeThisOuTfirga.sun.ac.za

At 12:49 PM 5/30/97 -0500, you wrote: >>Look in the window and compare die sizes. > >>Andy > >Exactly! If the die is smaller, allow more erase time. > >Jim Why is that ? Mike Some say there is no magic but, all things begin with thought then it becomes academic, then some poor slob works out a practical way to implement all that theory, this is called Engineering - for most people another form of magic. Massen

>> Exactly! If the die is smaller, allow more erase time. >> > >The die is actually smaller, but (this might be a stupid question) why >would a smaller die take longer to erase? If the floating gates are >smaller, then less charge will be on them and then it would take less >time to remove it...? The percentage of area the Metal layers over the cells is actually greater as the Si gets smaller (ie as the Silicon shrinks, the metalization layers don't necessarily shrink at the same rate). This is a common problem with EPROMs as they get more dense. myke > >Niki >spamBeGonesteenkmpspamBeGonefirga.sun.ac.za > > "My ancestors didn't spend millions of years clawing their way to the top of the food chain, just so I could become a vegetarian"

At 09:18 AM 5/30/97 -0400, you wrote: >>> Exactly! If the die is smaller, allow more erase time. >>> >> >>The die is actually smaller, but (this might be a stupid question) why >>would a smaller die take longer to erase? If the floating gates are >>smaller, then less charge will be on them and then it would take less >>time to remove it...? > >The percentage of area the Metal layers over the cells is actually greater >as the Si gets smaller (ie as the Silicon shrinks, the metalization layers >don't necessarily shrink at the same rate). > >This is a common problem with EPROMs as they get more dense. > >myke Thanks Mike, I didn't actually know the reason why myself, only that smaller die means longer erase time. You really got me out of the pooh on this one! BTW. Look forward to your book coming out. Just make sure we can get it in Australia! Regards, Jim