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ADS1232: Typically voltage of temperature sensor

Mehmet Kendi
Prodigy 20 points
Part Number: ADS1232
Other Parts Discussed in Thread: ADS1118, ADS1220, ADS124S08, ADS1248

Hi everybody

Datasheet page 13 / TEMPERATURE SENSOR (ADS1232 only) / ... Typically, the difference in diode voltage is 111.7mV @ 25°C.
My question: how typically is this value? The datasheet creates the impression that this 111.7mV @ 25°C is pretty accurate,

At 28.3°C I measure 118.8mV (equivalent to 43.8°C). The device is following correctly while I increase or decrease the temperatur.
Vref: 4.96V

Do I have somewhere an issue?

Best regards

Mehmet

  • 0
    TI__Guru** 112715 points
    Hi Mehmet,

    Welcome to the E2E forum! Unfortunately I cannot find any specific data collected for the temperature sensor of the ADS1232. The accuracy of this sensor is not trimmed or tested at our device's final test. Some of our newer devices are well know for accuracy such as the ADS1118, ADS1220 or ADS124S08 as a few examples. The older devices like the ADS1232 are based on theoretical values as the diode characteristics are quite predictable. But as there is some process variation from device to device, there may be some differences which can be several degrees.

    There can also be some added temperature due to self-heating of the device, and package to ambient temperature differences. As you are seeing a very large difference, the only way to get a good idea of the temperature sensor response used in this device, you really need to use some form of calibration. Generally a two point calibration can be quite effective. It is quite possible that the initial 25 deg C value is incorrect. For the ADS1248, the 25 deg C value is 118mV, which is much more in line with what you are seeing.

    I should also mention that it is important to remove any device offset by initiating a self-offset calibration.

    Best regards,
    Bob B
  • 0 in reply to Bob Benjamin
    Prodigy 20 points

    Dear Bob, thank you very much for the fast and detailed reply.