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CC1352R: Seeking Recommendations for DAC to Generate 4-20mA Output on CC1352R-Based Board

surya
Expert 2395 points

Part Number: CC1352R
Other Parts Discussed in Thread: DAC161P997, DAC161S997, AFE78101, AFE78201, AFE88201, AFE88101, DAC8771, DAC8750, DAC8775, DAC7750

Tool/software:

Dear Experts,

We are designing a board based on the Texas Instruments CC1352R microcontroller and plan to integrate a Digital-to-Analog Converter (DAC) to generate a 4-20mA current loop output for industrial applications, such as sensor interfacing or process control. Could you please recommend the best DAC ICs or solutions that would be suitable for this purpose?

We are looking for a DAC that meets the following requirements:

  • Output Capability: Able to drive a 4-20mA current loop with high accuracy and stability.
  • Resolution: Preferably 12-bit or higher for precise control.
  • Interface: Compatible with the CC1352R’s communication interfaces (e.g., SPI or I2C or single wire (DAC161P997)).
  • Power Supply: Operates within a 3.3V power supply (or compatible with the CC1352R’s voltage levels).
  • Size and Integration: Compact footprint suitable for a space-constrained PCB design.
  • Additional Features: Support for external reference voltage, low power consumption, and robust performance in industrial environments (e.g., temperature range of -40°C to +85°C).

Additionally, we would appreciate guidance on:

  • Any external circuitry (e.g., op-amps, transistors, or resistors) required to implement the 4-20mA current loop.
  • Recommendations for loop-powered or non-loop-powered configurations, depending on the DAC.
  • Any reference designs, application notes, or evaluation boards that could accelerate our development.

Thank you for your expertise and suggestions!
Surya.

  • 0
    TI__Guru* 99445 points

    Surya,


    Is this transmitter an active or passive application? The difference is that a remote transmitter is a passive transmitter, where you have a remote device powered by a supply (maybe 24V). When you apply power to the remote transmitter, the current sunk from the supply is between 4-20mA. This current value is scaled to show the measurement of the transmitter. For example, if the transmitter is measuring a temperature from 0°C to 400°C, 4mA would represent 0°C and 20mA would represent 20mA. Measurement values would scale linearly through this range. Frequently, this is a two-wire transmitter that is a sinking device, sinking current from a power supply. Often, the loop power is used to power the transmitter.

    In the other case, the analog current output is an active transmitter. The device uses a power supply and the output is an adjustable current or a voltage. This would be what you would think of as a voltage or current source, either output would be adjustable.

    If the application is for a passive transmitter, you would use something like the DAC161S997 (SPI) or DAC161P997 (Single-Wire Interface). Another possibility would be the AFE88101 (16-bit), or AFE78101 (14-bit). These are both designed as the DAC for setting the current in the 4-20mA loop. If you need to be able to transmit lower than 4mA, then you might look at the AFE88201 or AFE78201. The last devices require more circuitry, including an op amp, transistor, and some precision resistors.

    If the application is for an active transmitter, you would use something like the DAC8750, DAC7750, or DAC8771 (DAC8775 is a four channel version). These devices have current outputs in several different ranges. The DAC877x devices also have an integrated buck-boost converter that can boost a single +12V supply higher voltages to drive the outputs. You could also start with a generic DAC with a voltage output and output a current using a voltage to current stage.

    Each of these devices described here have some amount of collateral describing these types of systems and what you would need to build them. Let me know what you need, and I can help better guide an answer.


    Joseph Wu