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TMAG5170: Magnitude Data (13-bit) vs Channel Data (12/16-bit)

Chad
Prodigy 130 points
Part Number: TMAG5170

Hi,

    How does the magnitude data compare to the sensor data? The magnitude data is 13-bit, the sensor channel data is signed 16-bit and the ADC data is signed 12-bit data. How do I relate or understand the magnitude in comparison to the channel or ADC data? 

thanks

  • 0
    Prodigy 130 points

    It appears to be a 2^4 difference, at least when the sensor channel data is averaging to have 16-bit signed precision. 

    Can you confirm this to be correct? Also the magnitude data should always be positive? So is the magnitude data really just a 12 bit number? With an unused sign bit as the 13th bit? 

  • 0
    TI__Mastermind 26335 points

    Hello Chad,

    Thanks for considering to use Texas Instruments.  If you do not use conversion averaging you are only able to get 12 bits of resolution from the ADC.  This is the max resolution you can get using the magnitude data.  Looks like Figure 7-9 has a typo.  The sentence below states on D01 to D12 are sent through SPI.  I will double check with my team though.

    So with regard to the resolution, say we were using the 50mT range option.  With averaging, we could expand a channel result to read as low as 50mT/(2^(16-1signbit))= 1.5uT, whereas the magnitude would only read as low as 50mT/(2^(12-signbit))=24uT.