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MSP430FR6972: How to measure higher input resistance than MSP430 ADC

Kz777
Expert 7895 points
Part Number: MSP430FR6972

Hi Champs,

 

If the MSP430 ADC input resistance is higher than MSP430FR6972 spec (Nom:0.5kohm), do you have any idea to connect ?

 

 

 

Regards,

Kz777

 

  • 0
    Guru 300330 points
    You could use any circuit simulator to find out after which time the sampling capacitor (Ci in figure 28-7 of the User's Guide) is charged sufficiently.

    Or reduce the source's impendance with a buffer amplifier.
  • 0
    TI__Guru**** 212117 points
    Hi Kz777,

    As Clemens mentioned, the Sample Timing Considerations are covered in Section 34.2.6.3 and Figure 34-7 of the User's Guide and the passive component specs are shown in Table 5-24 of the Datasheet so you could try to simulate results for high input resistances. Similar implementations rely on a buffer amplifier circuit, can you specify the application at hand?

    Regards,
    Ryan
  • 0 in reply to Ryan Brown1
    TI__Expert 7895 points
    Hi Clemens, Ryan,
    Thanks for your reply. Anyway, we decide to implement OP-amp for impedance match.
    Regards,
    Kz777

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