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CC2590: Output PA impedance and matching network

Marin Milovac1
Prodigy 10 points
Part Number: CC2590
Other Parts Discussed in Thread: CC8530,

Hi everyone, I have two questions regarding CC2590 range extender which i plan to use in conjunction with CC8530.

1. In the datasheet i could not find the output impedance value for PA, only for LPA.

2. Second question is what is this network for? I have done  some simulations and i saw it is not for frequency filtering so i presume it is for impedance matching? Is it for 50 Ohm or some other value?

Thank you in advance

Marin Milovac

  • 0
    TI__Guru**** 317180 points

    For range extenders it's very important for the PA to see the wanted impedance to avoid instabilities. In addition filtering is required to attenuate harmonics to pass regulations. The network you have circled is combined impedance matching and filtering to get the wanted attenuation. Note that also the PCB traces to AVDDx are part of the matching since these have to be viewed as inductions. 

    It's not possible to condense the requirements into one or two impedance numbers in the datasheet hence we urge customers to follow the reference design as closely as they can to get a design that has the performance stated in the datasheet. 

    For customers that for some reason can't follow the reference design they can simulate our design (The PCB HAS to be included in the simulation) and ensure that the network used has the same transfer function as TIs reference design. This include the tracks to AVDDx