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Original question:

Comparison between simulated results and the ones in datasheet of THS4303

THS4303: THS4303 coupling

Links
Intellectual 2930 points
Part Number: THS4303

THS4303 is used in ADS to compare the effect of loading the recommended decoupling circuit and not loading the decoupling circuit：

For my design, the effect is better without adding decoupling circuit, but the effect is very poor after loading the recommended decoupling circuit.Therefore, whether the recommended decoupling circuit needs to be loaded when THS4303 is used for simulation in ADS, and the reason for such a big difference between the two.If the decoupling circuit is not required to be loaded during simulation, whether the actual layout needs the decoupling circuit

  • 0
    Guru 140200 points

    Hi Jiahui,

    can you show your layout? I ask because in 2GHz circuits the layout plays a dominant role.

    Kai

  • 0
    Guru 48395 points

    Regardless of what ADS shows, you will need some supply decoupling - the ckt you show is pretty thorough for an EVM environment - on a application board, at minimum put the required caps  at the supply pins. 

  • 0 in reply to kai klaas69
    TI__Intellectual 2930 points

    Hi all

    This is my PCB layout, the decoupling circuit in the BOTTOM layer, THS4303 in the top layer

    BOTTOM

    Bottom

    Now I'm doing as shown in the figure below negative impedance converter, for loading decoupling equivalent electric circuit of the negative resistance and no load decoupling equivalent of negative resistance difference is very big, so I want to know whether the simulation in the ADS need to be loaded decoupling circuit, if don't loading decoupling circuit simulation, in the final production loading decoupling circuit results should also be much worse.Because in the simulation loading and not loading results are much worse

     

     When the schematic simulation is carried out in ADS, L2 is loaded decoupling circuit and L is not loaded decoupling circuit. The negative inductance obtained from 0GHz-0.3GHz simulation will have a great difference

     

     

    Best Regards,

    William

  • 0 in reply to Links
    Guru 140200 points

    Hi William,

    maybe I'm too dumb. But can you tell me where the OPAmp is sitting in the layout?

    Kai