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TMAG5170-Q1: Current consumption and CORDIC algorithm

Part Number: TMAG5170-Q1
Other Parts Discussed in Thread: TMAG5170

Dear Sir, Madam

I saw on the datasheet of the component the current consumption in continuous conversion mode is about 3.4mA, however it is written in "test condition" it was done with /CS high. So I would like to know if this consumption is when we put a "high" level in input of the pin (so the system doesn't communicate in SPI) or when the pin is in "high" level (so we put a "low" level in input of the pin and the system communicate). If it is the consumption when the system doesn't communicate, could you give me the current consumption when the system is in communication in continuous conversion mode please ?

Is the CORDIC algorithm editable by the user or not ?

Is the use of CORDIC modify the current consumption ? If it is, what is the current consumption ?

I look forward to hearing from you.

Arnaud LANDRI

  • Arnaud,

    Thank you for reaching out with your questions.  We don't expect that you'll observe significant changes in current consumption during either case.  The CORDIC algorithm is quite an efficient means to generate angle data.  During SPI communication, input buffer switching tends to be a very minimal current consumption vs. a static behavior, so the main concern would be the one output buffer of the device and any necessary current to drive this net.

    thanks,

    Scott

  • Scott,

    Thank you very much for your answer.

    I don't want to modify the algorithm used in the CORDIC. In fact, for our project, the use of software has a lot of constraints to respect and we would like we can't have access to it and modify it. So it's for this reason I want to know if the user can have access to the algorithm and modify it or if it is protected and the user can't modify it.

    Also, I would like to order the TMAG5170A1EDGKRQ1 but I see it is out of order on all websites I saw (yours included). Do you have 10 samples that you can provide us please ?

    Best regards.

    Arnaud

  • Scott,

    I received a mail from TI which say me my chat wasn't send, so I send it to you again.

    Thank you very much for your answer.

    I don't want to modify the algorithm used in the CORDIC. In fact, for our project, the use of software has a lot of constraints to respect and we would like that we can't have access to it and we can't modify it. So it's for this reason I want to know if the user can have access to the algorithm and modify it or if it is protected and the user can't modify it.

    Also, I would like to order the TMAG5170A1EDGKRQ1 but I see it is out of order on all websites I saw (yours included). Do you have 10 samples that you can provide us please ?

    Best regards.

    Arnaud

  • Hello Arnaud, 

    There is no access to modify the CORDIC calculation inside the TMAG5170.

    While the Q1 version is out of stock, you can use the non-Q1 version (TMAG5170) to evaluate the device. The difference between the two versions is functional safety and automotive qualification for Q1 version. 

    Best Regards, 

    Justin Beigel

  • Hello Justin,

    Thank you for your answer, I will look at that with my colleagues.

    Also I have an other question about the temperature drift. In the datasheet it is written the temperature drift is worth maximum 2.8%, but is it 2.8% of magnetic field measured ? Is it 2.8% of angle measured (or angle calculated) ? Or is it 2.8% of an other thing ?

    Best regards.

    Arnaud LANDRI

  • Arnaud,

    The +/-2.8% specification is for sensitivity drift of any individual axis of TMAG5170A1 in either the +/- 25 mT or +/- 50 mT ranges. This specification is referring specifically to the drift from 25C to 125C. There is somewhat higher drift when taking the part to -40C.

    Angle measurements, however, will more closely depend on the sensitivity mismatch specification.  Supposing ideal inputs which are equal in amplitude and 90 degrees separated in phase, equal shifts in sensitivity will produce no angle error.  If instead there is some sensitivity mismatch, then the resulting output magnitudes will no longer be equal.  This will produce a non-ideal input for the CORDIC, and there will be some angle non-linearity.

    The sensitivity mismatch spec is shown here:

    Thanks,

    Scott