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MSP430I2020: PGA error specification

HS FAE Germany
Mastermind 32930 points

Part Number: MSP430I2020

Hello,

regarding the PGA customer would like to know how the gain error (Eg) differs between the different PGA settings.

In the data sheet the Eg parameter is specified for SD24GAINx=1,8,16 with Min -1% and Max +1%. What does this exactly mean ?

- Can each channel deviate -1 to +1% from the gain spec ?  

- Can a gain of 1 have a -1% gain error while a gain 8 will have a +0.5% gain error ?

- Or will all gains have the same gain error of -0.5% ?  Or even the same absolute error.

- What is the case with the gains 2 and 4 as they are not listed ?

 Customer has dynamically switching between multiple gain settings, and are planning to calibrate only one gain.

Regards, Holger

  • 0
    TI__Mastermind 49692 points

    Hello Holger,

    Please take a look at the following thread.

    Regards,

    James

    MSP Customer Applications

  • 0 in reply to James Evans
    TI__Mastermind 32930 points
    Hello James,
    so all gains have the same error of +/-1%? Doesn't matter of gain=1 or gain=16?
    - Is the error temperature dependant? Or is quiet better in the range of 0 to 50°C?
    - Can the eror be calibrated in production?

    Regards, Holger
  • 0 in reply to HS FAE Germany
    TI__Mastermind 32930 points
    Hello James,
    please reply on this tread.

    Regards, Holger
  • 0 in reply to HS FAE Germany
    TI__Mastermind 49692 points

    Hello,

    HS WG-FAE said:
    so all gains have the same error of +/-1%? Doesn't matter of gain=1 or gain=16?

    Did you look at Table 5-22 in the MSP430i2020's datasheet? It clearly states that the gain error is +/-2%. Did you read the thread that I linked in my earlier post? Britta clearly says that the gain error of +/-2% applies to all gains.

    HS WG-FAE said:
    Is the error temperature dependant? Or is quiet better in the range of 0 to 50°C?

    Yes, please refer to the gain error temperature coefficient parameter provided in Table 5-22 in the datasheet. It varies across temperature, and I'm not sure if it's better in some temperatures than others.

    HS WG-FAE said:
    Can the eror be calibrated in production?

    Yes, but I would encourage you to think outside of the device and think system-level. There will be component-to-component variations as well as board-to-board variations and silicon-to-silicon variations that will all influence the measurements, which is why calibration is performed.

    Regards,

    James

    MSP Customer Applications

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