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Recent content by _John

  1. J

    I thought I'd measure the leakage current of a few caps

    Thank you. I haven't had to take a measurement at that low of current. I see the Keithley 610B electrometer has some pretty good specs in the current measurement mode--I figured the meter noise would be larger than that (+/-3 fAmps). Does your test circuit pick up much noise when taking these...
  2. J

    I thought I'd measure the leakage current of a few caps

    Interesting--thanks for sharing. Care to also share what circuit (or equipment) you used to measure such a small current?
  3. J

    AT25128 Mass Erase / Write Lock

    On these four DUTs I was able to recreate the issue easily every time--typically within an hour of being at -40°C. I modified the four PCBs which had this issue and took off the AT25128 parts and soldered on M95128 parts (ST equivalent EEPROM). Last week I spent several consectutive days in the...
  4. J

    AT25128 Mass Erase / Write Lock

    I got more to fail. Here are the markings of parts which failed at -40°C. DUT 1 ATMLP352 5DBD B .3X2692A DUT 2 ATMLP416 5DBD B .3Y4690A DUT 3 ATMLP348 5DBD B .3X1297B DUT 4 ATMLP482 5DBD B .3W2975C The third row markings were difficult to make out on the last two devices so what is written...
  5. J

    AT25128 Mass Erase / Write Lock

    I will provide the markings in the coming weeks. Right now I want to keep these assemblies full production intent for the remainder of my testing. Since they are sealed assemblies I cannot view the EEPROM chip right now. Unsealing the assembly introduces the slight risk of cracking a trace on...
  6. J

    AT25128 Mass Erase / Write Lock

    I have not performed those tests in the temperature chamber yet. I performed a lot of power cycling, brown out voltage, etc tests at room temperature before I ever went in the cold chamber and I never saw any anomalys. DiSa, did your issue result in all memory locations being written 0xFF...
  7. J

    AT25128 Mass Erase / Write Lock

    I did the following: - AT25128B was soldered down on a PCB assembly which is connected to a microcontroller SPI master (original post has more details) - At room temp, I successfully wrote all the data to EEPROM that I need in the application - I verified this by reading back the data and...
  8. J

    AT25128 Mass Erase / Write Lock

    Are you reading back all 0xFFs in the EEPROM also? I still do not have a solution with the AT25128B device. I am changing manufacturers and switching to ST to hopefully resolve this issue. I haven't determined root cause yet; but, I am getting close. When putting the device in the cold...
  9. J

    AT25128 Mass Erase / Write Lock

    Thank you for the great idea. I considered that also to prevent accidental writes/operations. Unfortunately our microcontroller has no spare outputs. I may need to free up some I/O pins if I can't resolve this issue soon.
  10. J

    AT25128 Mass Erase / Write Lock

    Thank you for your reply. Atmel does have some proprietery methods of mass erasing the chip; but, they do not share this procedure. They shared some of the details with me and from what they told me I am not accidentally entering this mass erase protocol. I have a decoupling cap right...
  11. J

    AT25128 Mass Erase / Write Lock

    Hello, I am using the AT25128B EEPROM and I have observed some strange behavior. I am storing data in approximately 15% of the addresses and what mysteriously happens is the stored data is all erased and becomes 0xFF. When diagnosing the issue I also see that the BP0 and BP1 bits of the status...
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