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Hi Team, 

How many EXCITATION CURRENT SOURCES are there in LTC2984?

  • Hi ,

        There are multiple configurable current sources (current DACs) in the LTC2984 - however, typically only one is active at a time based on the channel configuration. 

        Cases where more than one current source is active:

    1) Thermocouple open-circuit detect uses a separate current source  from the one used by the cold-junction compensation sensor (Thermistor, RTD, or Diode) - those are active at the same time during the conversion.

    2) 3-wire RTDs use two matched current sources applied simultaneously to cancel the effect of the sensor lead resistance.

    Hope this helps, 


  • Hi Logan,

    Thanks for the information.

    Typically only one is active at a time--> I understood this point.

    You told that, there are multiple current sources in LTC2984--> I just want to know how many configurable current sources are there in the device?

    For an example if I want to connect 3 types of RTD(PT500, PT100, PT1000) means I need to configure three different types of IDACs for each type. For this kind of purpose I am asking the number of configurable current sources.

  • Hi

         The excitation current setting is part of the channel configuration. By specifying the type of sensor (RTD), the connection (2, 3, or 4-wire), and the excitation current, the LTC2984 will configure the IDAC appropriately. They are reconfigured based on the channel configuration word at the beginning of each conversion - there is no setting for the IDAC separate from the sensor configuration. 

        If you have not done so already, please download and play with the TestBench GUI (Demo Software) here: - you do not need the evaluation kit hardware to configure channels and view the 32-bit channel configuration word.


  • Hi Logan,


    I have one more query, How much data rates LTC2984 will support?

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