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ADXL355 datasheet units

Category: Datasheet/Specs
Product Number: ADXL355
Software Version: Rev A

Hello,

I have some confusion with the datasheet for the ADXL355 datasheet (https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL354_355.pdf). There are tables for high pass filter settings on pages 24 and 37, but the values given on 24 are 100x lower than the values on 37. Additionally, page 24 shows figure 61, with a cutoff listed at 9.8801[kHz] for 4[kHz] ODR which is incompatible with the 1[kHz] lowpass filter. Based on what I can measure in the lab, it seems like the values in table 10 are correct and the units in figure 61 are mislabeled (should be Hz). Can anyone confirm this, or am I reading something incorrectly?

Thanks,

Hayden

  • Hi Hayden, 

    Maybe I don't understand the problem correctly, but I do not think the datasheet is mistaken in this case.

    Figure 62 in the datasheet shows the HPF cutoff frequency is 9.88Hz for 4kHz ORD and HPF_CORNER = b'001. From the equation described Filter register in the 24.7*1e-4*4000 = 9.88Hz.

    Regarding to the figure 61, that figure it is a simulation of the decimation filter (digital LPF) response for 4000Hz ODR setting. The text in page 24 also mentions "Note that Figure 61 does not include the fixed frequency analog, low-pass, antialiasing filter with a fixed 3 dB bandwidth of approximately 1.5 kHz." 

    I hope this helps, 

    Pablo. 

  • Thanks for the prompt response. Based on your response I can see we are reading different data sheets. I looked online for a revision and found Rev.B, which is accurate as you described. I trusted the linked datasheet on DigiKey, which goes to Rev.A, and contains the errors I described, so my mistake.

    As a side note, the difference between these data sheets is Rev.A is referred to as "ADXL354_355.pdf" (see link in my comment) and Rev.B is referred to as "adxl354_adxl355.pdf" (https://www.analog.com/media/en/technical-documentation/data-sheets/adxl354_adxl355.pdf). This is quite confusing in my opinion, can something be done to redirect from Rev.A to Rev.B or at least make it more clear that a new revision is available in the old document?

  • Oh ok, I will let our editorial/web team know about your feedback, hopefully they can get this implemented.