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REF200: Alternative components, preferably through hole

Steve ***
Prodigy 10 points
Part Number: REF200
Other Parts Discussed in Thread: XTR101, XTR105

I am not even almost close to an engineer so be gentle.  I have been searching for weeks for a circuit that would provide a small current source to an RTD and I found this article titled TIDU969.  It was perfect just what I was searching for, however the components are all surface mount and I need to make 8 separate boards, too many surface mount components for the below average hobbyist. I am seeking advise on a circuit with through hole components that would accomplish this current source to excite an RTD. 

Again I loved this article, perfect explanation and I understood all the equations except 9.  I believe the 148 ohm should be 157.33 ohms; 148 ohms correlates to 125 degrees C.

Thanks for any guidance ,

Steve

  • 0
    TI__Mastermind 19500 points

    Hi Steve,

    The TIDU969 article uses a REF200 for the current source like you mentioned. There is many ways to create a current source and some that are even more precise than the REF200 but they are all mostly SMT. The only through hole solution I can think of is to use LM334/LM234 + diodes and resistors to create a constant current source. This will require a bit of calculations but there is an excellent example on pg 8 of the datasheet that you can follow to make 100uA current source. since this device only has 1 output pin, you will need to use 2 per board.

    -Marcoo

  • 0
    Guru 140200 points
    Hi Steve,

    you could use the XTR101 or XTR105.

    Kai