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MSP430I2041: DCO accuracy and ADC performance

Koichiro Tashiro
Mastermind 22945 points

Part Number: MSP430I2041

Hi,

My customer is considering to use MSP430i2041 and wants to use internal DCO.
According to datasheet, DCO has some variation.


The customer has concerns these DCO variation impacts to ADC performance.
I discusses it with MSP engineer and he said a few % of error in MCLK should not lead to the jitter on sample clock.
So only few % clock error will not impact ADC result.

I got additional question for above.
Q1) If a few % clock error does not impact ADC results, using DCO without an external resistor(+/-3.884%) is also acceptable?
Q2) It seems datasheet does not provide MCLK jitter specification. Do we have DCO jitter data?
Q3) The DCO jitter is same with/without an external resistor?

Thanks and regards,
Koichiro Tashiro

  • 0
    TI__Guru 71216 points

    Hi Koichiro-san,

    Koichiro Tashiro said:
    Q1) If a few % clock error does not impact ADC results, using DCO without an external resistor(+/-3.884%) is also acceptable?

    It is difficult to answer this question because I don't know if "a few %" is less than or more than the +/-3.8884%.  My guess is it is something less, so this would indicate not using the external resistor would lead to a larger %error.  How much error - I don't know.

    Koichiro Tashiro said:
    Q2) It seems datasheet does not provide MCLK jitter specification. Do we have DCO jitter data?

    Unfortunately, there is no DCO clock jitter data available. 

    Koichiro Tashiro said:
    Q3) The DCO jitter is same with/without an external resistor?

    There is no specification in the datasheet for this so it would be difficult to say if the DCO jitter is same with/without the external resistor

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