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REF200: REF200 Appliction

Naser S.
Genius 11605 points
Part Number: REF200

My customer  likes to use REF200 as their DC current source device to source 200uA to other device (capture below). Voltage rails available for this application are 1.2V, 1.8V, 3.3V.

Question, when produce 200uA from your device as current source:

  1. Which voltage rails should I use for this and which pins should I connect to?
  2. Which pins from your device should I use to connect to other device so it can source 200uA? And what voltage should I see on this line when it source 200uA?
  3. What should I connect your device pin 6 to?
  4. What should I do with unused pins?

 Regards,

Naser

 

 

 

  • 0
    TI__Intellectual 1540 points

    Hi Naser,

    The capture did not show up. Is this a 3-Wire RTD system?

    1. The REF200 needs at least 2.5V, so the 3.3V rail should be used.

    2. The 3.3V rail should be connected to pins 8 and 7, and pins 1 and 2 will provide 100uA each. Pin 1 and 2 can be connected in parallel to achieve the 200uA. The voltage on the output will depend on the load, since this is a current source and a current is set, not a voltage. However, there is a limit to how high that voltage can go, and figure 9 (below) from the datasheet can be used as a reference. In your case it appears that the minimum voltage drop is about 250mV. 

    3. The most negative potential in the system. If there are no negative rails, connect to ground.

    4. Leave pins 3, 4, and 5 floating.

    Regards, Diego