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XTR108: Getting started with current loop design

Part Number: XTR108
Other Parts Discussed in Thread: INA826, INA2331

Our team is getting started with 4-20mA current loop design and was searching for advice or recommendations.


Does  the XTR108 look correct? What is the recommended reference design for the XTR108? The provided reference (Fig.35 of SBOU123A) has many externals wrt to provided datasheet figure (Fig.2 of XTR108). There are also 33 posted reference designs for 4-20mA, is there a recommended design for use in our application?

E2E's help and advice is greatly appreciated by our team, reach out if any clarifications are needed!

  • Hi Justin,
    Are you looking for a 4-20mA receiver to receive the 4-20mA signal from the PMP21, or are you looking to re-condition the PMP21's 4-20mA output? My reading of the PMP21 technical information pdf is that the PMP21 already outputs a 4-20mA signal, so no 4-20mA transmitter would be required.

    If you're looking at re-scaling the 4-20mA output of the PMP21, you might want to consider another part than the XTR108 unless you need the programmable gain and offset calibration the XTR108 provides. While XTR108 can be used with various sensor types, much of its functionality is targeted at resistive bridge sensors or RTD temperature sensors. If you're just looking for a V-to-I converter, we do have a number of parts that accomplish that, depending on whether you need a 2-wire or 3-wire 4-20mA loop output.

    If you're looking for a receive-side circuit, there are a number of options we can recommend. A few op-amp based solutions are detailed beginning on page 37 of Another option would be to use an instrumentation amplifier such as the INA826 and a current sense resistor to measure the 4-20mA signal. An example circuit for a 4-20mA receiver using INA826 is shown in the INA826 datasheet in figure 63.
  • Justin

    We haven't heard back from you so we assume this answered your questions. If you need more help just post another reply below.

  • Hi Dennis, my apologies for the delay! The INA826 is an excellent choice, thank you for your recommendations this has been very helpful in our design work.

    Would the INA2331 be valid for a 2-channel solution?

  • Hi Justin,

    INA2331 should work fine for a 2-channel solution.