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RF430FRL154H: Required capacitors for RF430FRL154H?

Chris Larsen1
Prodigy 85 points
Part Number: RF430FRL154H

I am using the RF430FRL154H in a very compact design, and I would like to use fewer capacitors than that in the application circuit in the datasheet.  It shows capacitors on VDDSW, VDD, VDDH, VDDB, VDD2X SVSS, and RST as well as the flyback capacitor on CP1 and CP2.  I am only using the VDDH supply external to the chip.  Which capacitors should I populate, and which are optional?

It would seem as though VDD, VDDSW, VDDB, VDD2X, and SVSS caps are all not necessary for my application.  However, I noticed when I removed a cap from VDDSW/VDDB, the tag stopped responding.

  • 0
    Prodigy 85 points

    Just to be clear, VDDSW, VDDB, VDD2X, SVSS, and VDDD are not used anywhere else in my circuit.  It's just unclear to me which of these need decoupling for the IC to operate properly.

  • 0 in reply to Chris Larsen1
    TI__Guru*** 128255 points

    Hello Chris,

    See Section 2.3 of our FAQ for details on the required components: https://www.ti.com/lit/pdf/sloa247

    If you aren't using the ADC, you can omit the SVSS capacitor. If a battery isn't used, I feel that VDDB cap should be able to be omitted, but if it is used then it would not be able to be omitted. It sounds like you are doing RF power only though.

    VDD2X is required for device operation. VDDD is used for digital logic in the device so you would need that one.

    I am not entirely sure why the VDDSW cap would impact that, from what I am seeing I wouldn't anticipate that being the case. But if you were missing some of those other caps like VDD2X then that could explain it.

  • 0 in reply to Ralph Jacobi
    Prodigy 85 points

    Thanks!  When I started working with this IC, the FAQ didn't yet exist, so I didn't think to look for one.  This answers the question well.