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Issues  with EVAL-AD7294-2SDZ Current Sensor


I have both, the EVAL-AD7294-2SDZ and the EVAL-AD7294EBZ.

I got the EVAL-AD7294-2SDZ because it allows me to interface to the I2C without cutting traces.

However, I don't seem to get the Current Sensors to work properly.

It does however work in the EVAL-AD7294EBZ.

I do exactly the same setup as with the EVAL-AD7294EBZ. I modified the on-board sense resistors to be identical.

I also added a 1uF capacitor to suppress unwanted noise.

What I get is an extremely noisy data stream as long as the sense voltage is within +/-200mV.

I did make sure that all parts of the AD7294-2 are powered on.

Is there anything else that I need to do? Is there a bug in the eval software?

Regards and thanks in advance,



  • Hi, Arne.

    Do I understand that you installed the same Rsense for both evaluation boards? Can you send an illustration for both of your setup including the modifications you have applied? Please also send the data stream you are seeing so we can check on this better.



  • Hi Karen,

    In both boards I replaced the on-board sense resistor with 100Ohm.

    In addition to that, I am using an off-board sense resistor with 10milliOhms that is connected to the board via two coax lines with approximately 1m length.

    I wanted to have a decent size on-board sense resistor to keep line noise low.

    The EVAL-AD7294EBZ gives me a fairly clean signal, while the EVAL-AD7294-2SDZ gives me a signal that has basically full scale noise as long as I am within the +/-200mV window. I will see if I can get a screen shot from my setup.

    In this context, can you explain to me what the difference is between the AD7294 and the AD7294-2? I can hardly make out any differences in the data sheets.



  • Hi Arne,

    There is little or no difference between both parts. The power down mode for the AD7294 is a little different to that of the AD7294-2.

    I spotted an issue with the AD7294-2 Evaluation Board Software source code when I went to take a look. I spent today fixing it. Please just download and run the following. Let me know if you experience any issues:




  • Hi Padraic,

    Thanks, I will download the new code and install.

    I will be out for the weekend so you won't hear form me before next week.



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