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AFE4300 Current RMS, peak?!

user138497234
Intellectual 265 points
Other Parts Discussed in Thread: AFE4300

Hello, 

I'm wondering, if I'm stupid or the datasheet and the forum information are wrong. Datasheet and forum tells you that the current is at 375 µA RMS +- 20 %. So I expected to measure something between 300 µA and 450 µA with my True RMS Multimeter (Brymen BM869s).

But that was not the case, and I measured 268.33 µA RMS. Multiply that by sqrt(2) and you get 379.5 µA peak, which is close enough to the claimed 375 µA. But peak and not RMS. 

So my question is, if someone could measure his AFE4300 or maybe an official statement by some TI employees. 

Thanks in advance!

  • 0
    TI__Mastermind 49926 points

    Hello,

    You are right. This is a typo in the datasheet that we will be fixing in the next rev of the datasheet.

    The output of the DAC is a sine wave with a peak-to-peak value of 1V (rms value of about 350 mVrms).

    This voltage waveform is converted to a current waveform using an internal resistor RDAC of 1.5 Kohms leading to an excitation current of about 235 uArms.

    The tolerance of the RDAC is ± 20%; and the excitation current can vary by this extent.