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XTR111: XTR111

Yuxuan Tang
Prodigy 20 points

Part Number: XTR111
Other Parts Discussed in Thread: TINA-TI

I want to generate a double-exponential current pulse using XTR111, as shown below. 

By applying a double-exponential voltage pulse as the input for XRT111, I hope I can get a current pulse with similar shape. But the spectrum of the voltage/current pulse can reach up to ~5 MHz, which is beyond the XTR111 bandwidth (~ 1MHz, shown in Figure 3 of XTR111 datasheet), so I am wondering if the XTR111 can be used to generate the expected double-exponential pulse? Are there any other amplifiers that would be a better choice to generate the current pulse?

Thanks

  • 0
    Guru 140200 points
    Hi Yuxuan,

    figures 39, 40 and 41 of datasheet demonstrate that the XTR111 produces noise at its output which needs some low pass filtering to get a useful output signal. This will even further reduce the bandwidth of this circuit.

    Have you thought about using the "Howland Current Source" for this task?

    Kai
  • 0 in reply to kai klaas69
    TI__Expert 6275 points

    4-20mA transmitter will not work for this application.   You will need an wideband op amp Possible circuit arrangement is an improved Howland Current pump detailed in attached powerpoint.  Please study the attached collateral.  You will need to use a avery wideband op amp and need to determine what load you are driving to get high enough supply voltages and op amp voltage rating to deliver this current pulse.

    This should help answer your question.  

    In addition consider downloading the free SPICE simulator from TI, TINA-TI at:

    By building and simulating your circuit in TINA-TI many problems can be avoided before building it in the real world. If you have problems once the circuit is built in TINA-TI feel free to post the schematic from TINA-TI on the E2E Forum for further assistance.

    2728.Design and Apps Current Sources.ppt