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ADS1283: Electrical parameter report

Zhang Liang
Genius 4305 points
Part Number: ADS1283
Other Parts Discussed in Thread: ADS1282, ADS1282-SP

Hi,

We will use the ADS1283 for the new project, and we want to get the electrical parameter charger report after we use the ADS1283 about 1 or 2 years, thanks.

  • 0
    TI__Mastermind 18900 points

    Hello Zhang,

    I've heard "electrical parameter charger report" before but I'm to assume you meant Electrical Parameter change report which I interpret as aging or long term drift. Please correct me if I misunderstood your request.

    Unfortunately, it does not look like we have any long-term drift data specifications for the ADS1283. In fact, none of our ADS128x family has long term drift data, even the ADS1282-SP which is the Radiation Hardness Assured version of the ADS1282. For future reference, specifications with the phrase "Long-term" is what should be searched in the datasheet.

    Unfortunately, these long term specifications are measured, not simulated. As a result, I can only make generalizations about the spec. From what I understand, most design rules allow for no more than 2 times the maximum specification over the lifetime. Again, I want to emphasize that this is not a guarantee and the device most likely is much less than that. But if you need a number, this should help you.

    I will also say that I've never seen an ADS1282-SP customer ask for this specification. Maybe that is a good sign for your project.  

    Best,

    -Cole

  • 0 in reply to Cole Macias
    Genius 4305 points

    Hi Cole,

    Many thanks for your detial reply, this is very useful for us, and I have below issue:

    1. Our engineer wants to know the electronics parameter charger report to evaluate the tolerance to calculate the absolute rating, we can assess our product working life when we design the product specification, and the ADS1283 is the very inportant device for our product, so please kindly check if there are any report or explain;

    2. I have download the "Ongoing reliability monitoring" report from TI websit, and this is only the temperature or humidity tesing condition, and there are no any detial explain to the paramater charge.

    3. Please kindly supply fhe mean of "2 times the maximum specification over the lifetime", what is the base? Typical or other parameter, thanks?

  • 0 in reply to Zhang Liang
    TI__Mastermind 18900 points

    Hello Zhang,

    In general, these answers are very statistically driven. As such, they aren't very concrete so I'd like to apologize in advanced for that. That being said, if the customer isn't familiar with the concepts in this TIPL video, they need to watch it: https://training.ti.com/ti-precision-labs-adcs-statistics-behind-error-analysis

    1. ...evaluate the tolerance to calculate the absolute rating

    In the case where only a typical spec is given, you can multiply by +/-3 or +/-4 the typical depending on the tolerance of your design. The gaussian distribution assumes that +/-1 standard deviation is contained with the typical value which is why +/-3 or +/-4 will give you the absolute maximum. This TIPL should be able to help explain these concepts. https://training.ti.com/ti-precision-labs-adcs-statistics-behind-error-analysis

    2. I have download the "Ongoing reliability monitoring" report from TI websit, and this is only the temperature or humidity testing condition, and there are no any detail explain to the parameter charge.

    That's correct. Those details are on a pass and fail criteria and failure is defined as a device that falls outside of any listed maximum specification (or catastrophic functional failure).

    If the device was tested for shifts, then the specs will be in the datasheet. If the shift parameters don't exist in the datasheet, then they were not tested. In the case of ADS1283, we don't have anything in regard to humidity or temperature shift in the datasheet which means they were not tested to quantify the shifts.

    3. Please kindly supply the mean of "2 times the maximum specification over the lifetime", what is the base? Typical or other parameter, thanks?

    The way to interpret this is that any specification that falls within ranges of the absolute maximum will shift no more than +/-2 times the absolute maximum if listed. As mentioned previously, if you only have a typical you might want to adjust for the maximum.

    In addition, the video talks about the combination of multiple worst case scenarios and how they are statistically unlikely. Generally speaking, this generalization is the culmination of design rules for a worst case scenario. Using the +/-2 times the typical may make more sense for a real system. Again, this all depends on the risk of the design analysis.

    General comments

    It looks like that this analysis is in the pursuit of error analysis over time. Root sum of squares show that an error value doesn't contribute much if its not within ~3x the largest error source(s). I'm very skeptical that humidity or age drift of INL or offset, for example, will contribute more than temperature drift of offset. I do encourage the analysis though, I'm curious what they come up with. 

    Best,

    -Cole