EPROM Erasing time? 15mins or 55mins is bad?

[ChrisP58]

How many times can One EPROM chip be erased? how my erase cycles?

You need to get that from the datasheet for the actual part you are using. But I would guess only a few thousand. That sounds like a lot, but if they've been part of a test process for 15 years...............

 

[blueroomelectronics]

Why on earth is anyone still using UVEPROMS? What product are you finding them in that isn't yet landfill?

 

[Billy Mayo]

They still use them at my work for a Logic control board

 

[KeepItSimpleStupid]

Might there be a more modern drop-in replacement for them? e.g. FRAM, EEPROMS, DALLAS RAMS, FPGA

@Blueroomelectronics: As for devices that may use UV proms - Vintage Tektronix scopes. You would put them in a landfill? Shame, Shame.

 

[blueroomelectronics]

Might there be a more modern drop-in replacement for them? e.g. FRAM, EEPROMS, DALLAS RAMS, FPGA

@Blueroomelectronics: As for devices that may use UV proms - Vintage Tektronix scopes. You would put them in a landfill? Shame, Shame.

I'm sure the UVEPROMs are fine in those old scopes, I can't envision Tektronix expecting anyone to update them. I agree there was probably a drop in update for UVEPROMs when they were being phased out but that was a long time ago.

 

[KeepItSimpleStupid]

There is plenty of activity in the Tekscopes Yahoo group on updating the firmware for the old Tek scopes and I can point you to site with lots of firmware images for HP, Tek and other equipment.

Aside:
One of the issues facing owners of scopes is primarily the replacement of the Dallas Backed up RAM which hold the calibration data. Some scopes used the Dallas parts and others used an external battery. The Dallas parts are still available, but one needs to remove, copy and replace or in the case of the external battery, keep a source of power while the battery is replaced.

 

[mvs sarma]

Even the UV light source has aging effect and might need replacement. Perhaps a erasure test from a different eraser could reveal the behavior of the eprom under consideration.

 

[Mr RB]

Yep. As I said before he needs to test the erasing time, by doing runs of 1 minute each and testing the part. Once you know roughly how long an erase takes you just add a safety margin to that. At this point the O.P. seems to be guessing how long an erase takes, and guessing about what the fault actually is.

 

[Billy Mayo]

The Datasheets says 15 mins Max. to Erase

When you Over- Erase the EPROM chip, it Kills the Cells , and the Cells has less and less electrons each time you erase over and over too

We use White Labels that are sticky on the bottom to cover up the UV Hole after we have programmed them, I now use a black maker to blacken the White label so no light gets in.

Next I need to check the Vpp and if the programming is right

The Main Issue We are Having is:
1.) After we program the EPROM chips, after a week or so they will start to create distorted waveforms and digital errors , etc. I have seen the waveforms on the oscilloscope and they are all different kinds of waveshapes and distortions

Can you list what can be causing these problems?

 

[blueroomelectronics]

Sounds like the EEPROMs are deteriorating, too may erase / write cycles, age.
Not sure how effective paper and black marker is at blocking UV, we used foil stickers back in the day.

 

[ChrisP58]

Take the eproms back to the programmer and verify that their content matches what was programmed into them previously. If they're changing then you can look to see why. I would suggest looking for a EEPROM equivalent and chucking the UVEPROM parts entirely. They're probably much cheaper too.

If you do stay with the UV parts, the cover stickers should be foil. Black may be black to visible light, but may not be opaque to UV.

 

[mvs sarma]

there are specific stickers that are UV filters.Try to get and use them. Perhaps black PVC electrical tape might even work. Ensure that the Vpp pin used for program loading is not kept floating in the user circuitry.

 

[Mr RB]

The Datasheets says 15 mins Max. to Erase
...

Again, you are guessing. The real time depends on the age and brand of the UV tube, and the amount of power the tube is getting, and the distance from tube to chip, and type of chip.

And the "15 minutes max" implies that a normal procedure would end in much less than 15 minutes.

It only takes some minutes to do a test and find out the actual erasing time. It's up to you if you bother doing it.

When you Over- Erase the EPROM chip, it Kills the Cells , and the Cells has less and less electrons each time you erase over and over too
...

Which is exactly why it is worth doing a couple of simple tests.