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ADS1015-Q1: 3 Failed parts when exposed to surface temperature >65 deg C

Kavin Kumaravel
Prodigy 20 points
Part Number: ADS1015-Q1

Tool/software:

Hello Team,

We are currently using this ADC in our product to acquire four analog signals (AIN0 to AIN3), all of which are connected.

After thorough investigation, we have isolated an issue that appears to be within the ADC itself.

Issue Description:

  1. In a small number of units,  3 samples out of over 30,000 products, we’ve observed incorrect readings specifically on AIN2 when the surface temperature of the ADC exceeds 65°C.
  2. AIN2 is configured to measure an amplified current signal.
  3. We have verified that the analog input to the ADC is accurate and stable.
  4. However, the digital value read by the microcontroller from the ADC for AIN2 is incorrect, it appears as garbage data.
  5. The other input channels (AIN0, AIN1, AIN3) continue to function normally under the same conditions.
  6. Based on our analysis so far, the issue is not with the analog signal chain but seems isolated to the ADC’s behavior at elevated temperatures.
  7. Could also be an issue with i2c.
  8. When temp <65 deg, ADC works as expected.

As i had mentioned, we are not seeing this behavior in all parts but only few and in these few issue is  reproducible.

Have you seen this behavior before? Could you please support and share the FTA for the same. Thank you

  • 0
    Prodigy 20 points

    Exact part number: ADS1015AQDGSRQ1

  • 0 in reply to Kavin Kumaravel
    TI__Genius 15150 points

    Hi Kavin,

    Thanks for taking a thorough look into this. This isn't an issue that has come up before. Can you share what the expected ADC values are, and what the corresponding garbage data is? How is "garbage data" classified in this case?

    Regards,
    Joel

  • 0 in reply to Kavin Kumaravel
    TI__Genius 15150 points

    Hi Kavin,

    I've sent you a friend request so we can get more information on the specific devices over email. Let me know also if it is okay to email you directly.

    Regards,
    Joel

  • 0 in reply to Joel Meraz
    Prodigy 20 points

    1. Our analog current measurement unit converts -5A to 50A into a 0–5V output, which is fed directly into the ADC.

    2. The ADC input range is 0–5V, and we have thoroughly tested various scenarios across this range.

    3. Once the ADC surface temperature exceeds 65°C, we observe a sudden and significant rise in the digital output (ADC counts) on all AIN

    4. The input signal remains accurate and stable, verified with external measurement equipment.

    To debug further, we developed custom firmware that reads raw ADC values via a serial interface. The attached image shows a graph of all four AIN inputs and corresponding raw data captured by the microcontroller.

    We have completely ruled out the firmware as the root cause. The issue occurs across different software versions and was validated using raw data monitoring and code-level analysis.

    Current Suspicions:

    1. ADC (Integrated I2C interface)

    2. Isolator (ISO7763FQDWRQ1) – this component sits between the ADC and the MCU.

    Given the severity of this issue, we are forced to halt production of affected units until a root cause and solution are confirmed.

    We are also requesting our purchasing department to escalate this matter with our contacts in the TI support and purchasing teams.

  • 0 in reply to Kavin Kumaravel
    TI__Genius 15150 points

    Hi Kavin,

    Thank you for the response, and for conveying the severity of the issue. I've reached out to you on private message with my email, so we can discuss the details.

    Regards,
    Joel