Other Parts Discussed in Thread: REF200, LM317, ADS1247, ADS1148, ADS1147, ADS1248
Hello,
I would like to design a circuit with 4-wire measurement technology for a resistor. This resistor itself is integrated in a resistor matrix of other resistors with which the heat distribution on this surface can be simulated. The resistor for the temperature measurement in the center has an area (l x w) of (820 x 100) µm^2.
This has the following specification (datasheet):
Sensor type: meander-structured resistor
Sensor connection: 4-wire-connection
Resistance value (25 °C): 3.2 +/- 0.1 kOhm
Sensitivity: 10.0 Ohm/ (theoretical value based on the Ti temperature coefficient)
(In fact I don't even have these test chips right now - and I am dependent on this information)
The type of resitor is supposed to be an RTD, although the nominal value seems too high to me. A wanted temperature range of T = -20 °C toT = 120 °C results in a resistance value of R(-20°C) = 2.75 k to 4.15 k which results in a voltage drop of 1,1 V to 1,66 V at the resistor, which I would like to amplify with an OP to 0 to 5 V to feed into an IO-HW? The offset should ideally be trimmed to zero by HW (but this could also be done by SW if necessary).
What do you think? Could this be realized with an OP INA333 (4-wire) or INA 326 in three wire circuit? And could you use the LM317 or better the Ref200 as constant current source? I would be very grateful for support.
Best regards, Bernd
