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MSP430F6747A: Recommended capacitor values

Part Number: MSP430F6747A

Hi,

My customer is using MSP430F6747A for production.
Customer is planning to update their PCB and some capacitors on board needs to be replaced.

Below values are recommended in datasheet.
VREF: 100nF(nom)
DVCC: 4.7nF(min)
AVCC: 4.7uF(nom)
AUXVCC3: 0.47uF(nom)

What are expected impact if these capacitance values are lowered?

Thanks and regards,
Koichiro Tashiro

  • Hi,

    I assume the application is in the metering area, and utilizing on one hand the ADC functionality of the device and on the other hand is subject to high robustness requirements against ESD/EMI.

    Both aspects can be negatively influenced by reducing the capacitor values, but as the capacitors are not the only factors influencing the analog performance and robustness versus electromagnetic interference, it is not possible to quantify the quality of the impact. Only the tendency of the trend towards worse performance can be assumed.

    The other factors influencing the analog performance and robustness is the HW design, layout and the resulting signal integrity. Also the power supply design and architecture has a decisive impact. But as all these aspects are design specific, we can only recommend to test the analog and robustness performance with the reduced capacitor values, before making the decision for mass production.

    One additional aspect to keep in mind is the min. specified backup capacitor for the DVCC. Please keep in mind the MSP430F6747A has an integrated power management including an LDO on chip. Going below the recommended minimum value of the supply capacitor might negatively impact the stability of this LDO, with respective results on the safety of operation of the MSP.

    Best regards

    Peter

  • Hi,

    under the assumption your questions have been answered sufficiently, I am closing the thread. In case you should have additional questions, please let us know.

    Best regards

    Peter