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ADS1247: When using ADS1247 to read 10K NTC temperature sensor ADC, there will be a cycle fluctuation of about 10 seconds

user6260564
Prodigy 20 points
Part Number: ADS1247

Tool/software:


Read a 10 KNTC temperature sensor and configure a 39K sampling resistor for periodic fluctuations at room temperature. Using an external reference voltage source, a 50uA current source, PGA = 1, and DR =80SPS, there will be approximately 10 seconds of periodic fluctuations. This kind of jitter should be ruled out as an external cause. I would like to ask if it is caused by configuration issues or circuit problems.

  • 0
    TI__Mastermind 48951 points

    Hi user6260564,

    If you measure the ADC inputs at the ADC pins, do you see the same fluctuations? You might need to use an oscilloscope

    If you measure the reference voltage during this time period, do you see any fluctuations?

    Can you provide a schematic of your system?

    Can you try using the internal voltage reference to bias the resistor divider (NTC + sampling resistor) instead of the current source? Then the system will be ratiometric, where the biasing source (ADC REFOUT) excites both the sensor and is used as the reference voltage.

    -Bryan