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XTR116: DAC out to 4 to 20mA conversion.

Sagar Rathod
Prodigy 115 points
Part Number: XTR116

Tool/software:

Hello, 

I am going to use XTR116 this IC and I am procuring  RDL 4-20mA Current Loop Transmitter XTR116U with Analog Input from Amazon Web, for prototype.

My application is I want to convert STM32L151C8T6A  DAC out voltage to 4 to 20mA output.

The DAC Minimum voltage is 0.1752V and Max Volt is 3.0998V that i want to convert it into 4 to 20mA respectively. This should give linear with DAC out, with high accuracy without calibration.

Let me know my selection of IC is right or wrong, I would appreciate if give more details about connections.

The Max load for 4 to 20mA is PLC or any data logger may can consider.

Thank you.

  • 0
    TI__Guru 63351 points

    Hi Rathod,

    Sagar Rathod said:
    The DAC Minimum voltage is 0.1752V and Max Volt is 3.0998V that i want to convert it into 4 to 20mA respectively. This should give linear with DAC out, with high accuracy without calibration.

    You may define your own input voltage range to the XTR116 V-to-I conversion. If you decide 0.1752V ≤ Vin ≤ 3.0998V, Iout between 4 and 20mA is proportional to the Vin, here is the simulated example. 

    XTR116's current gain is 100A/A, and input current needs to be between 40uA to 200mA, derived from Iout = slope*Vin + b, slope = 160uA/(3.0998-0.1752), b's current is determined by 4.096V/Ros. 

    XTR116 0.1752V = Vin = 3.0998V 07052024.TSC

    If you have additional questions, please let me know. 

    Best,

    Raymond

  • 0 in reply to Raymond Zhang1
    Prodigy 115 points

    Hello Raymond,

    Thank you for valuable answer, TIP41C which is used at output side, can I use any other transistor like SBC817-40LT1G or any other with same package, the TIP41C package is bigger, so suggest any  SOT-23-3 package for same application. 

    Thank You.

  • 0 in reply to Sagar Rathod
    TI__Guru 63351 points

    Hi Sagar,

    Here is some other suggestion, including one SOT-23 package NPN transistor. 

    You would need to select one with lower thermal resistance (Junction to ambient, power dissipation curve), low Cbe and Cbc parasitic capacitance, and it has 2X-3X design margin to handle the Vloop voltage including safe operating area for your application. 

    If you have other questions, please let me know.

    Best,

    Raymond