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VIN and REFIN on the AD7747

Question asked by ChristianGoetzen on Sep 14, 2013
Latest reply on Sep 16, 2013 by seanbrown



in the datasheet for the AD7747, figure 38 on page 25 (rev.0) shows how to connect an RTD. However, I don't understand how to choose the resistor between REFIN(+) and REFIN(-). Should it be equal to (or rather a little bit higher than) the maximum expected value of the RTD?


Secondly, can I change the circuit so that REFIN(+) is connected to VDD, REFIN(-) to VIN(+) and VIN(-) to GND? The RTD I want to measure is unalterably connected to ground.


Thanks in advance,

Christian Götzen