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.
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.
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: https://www.analog.com/en/products/ltc2984.html#product-requirement - you do not need the evaluation kit hardware to configure channels and view the 32-bit channel configuration word.
