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TMAG6180-Q1: continuous calibration

Shinji Tsuji
Genius 15394 points

Part Number: TMAG6180-Q1

Hi team,

I have a question about Angular performance spec in the datasheet 5.6 magnetic characteristic. 

ANGERR_DYN_DE = Angular error linearity across temperature on continuous calibration(gain/offset) 

Does this "continuous calibration(gain/offset) mean device internal "offset compenstion and Automatic Gan Control"? Or does it mean the calibration doen by user(7.1.3 calibration of sensor errors)?

 

regards,

  • 0
    TI__Mastermind 25530 points

    Shinji-san,

    Thanks for reaching out on E2E.  The continuous calibration is done by the customer.  The idea of this calibration is that as temperature changes they can continually track peaks of sine and cosine outputs and adjust amplitude and offset corrections as needed.

    Thanks,

    Scott

  • 0 in reply to Scott Bryson
    TI__Genius 15394 points

    Hi Scott-san, 

    6.3.5 Automatic Gain Cotnrol (AGC) is always enabled continuous calibration is expected on top of this AGC, correct?

    regards,

  • +1 in reply to Shinji Tsuji
    TI__Mastermind 25530 points

    Shinji-san,

    You are correct that AGC is always enabled in TMAG6180-Q1.  The device will ramp the AGC initially at power-up and stop when the outputs are within tolerance of the 60%FS target.  If Vcc varies significantly during operation, we may see the AGC attempt to adjust the amplitude.  The continuous calibration would account for this, however.  The calibration should monitor the peak value of both SIN and COS and then normalize them to each other by applying a scalar prior to the arctangent calculation.  The goal is that the ratio of the amplitudes is equal to 1 so that we get the best linearity from our arctangent calculation.  Any time the AGC is adjusted, we might see some minor change to this ratio which would then be updated.

    Thanks,

    Scott