Bandwidth of AD8000 in non-inverting configuration

I have a AD8000 SOIC package in noninverting configuration (Fig. 50 datasheet). Rf=439 ohms, Rs=0ohms, RL is open circuit, Rg = open circuit, 0.1 uF decoupling caps at supply pins. I am using +/-5V supply. I am interested in the performance at 1.25 GHz. I use -20 dBm input and get -26 dBm output at 1.25 GHz. I don't think this matches the performance shown in Fig.5 of datasheet. Can you suggest what I could change to make it work as expected?

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    •  Analog Employees 
    on May 16, 2017 11:31 PM

    Hi Atul,

    Could you run a frequency sweep on your setup? By that we could see the actual response of the amplifier. In Figure 5, at G=+1, the gain is rolling off rapidly after 1 GHz. This means that a very small change in frequency is a drastic decrease on the gain. The best way to see this is on a frequency sweep on your current setup.

    The variation on your result and on the table 5 is due to parasitic capacitance present on your board. This greatly contributes on the decreased bandwidth as compared to the defined value in the said table.


    Regards.

    Jino

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  • 0
    •  Analog Employees 
    on May 16, 2017 11:31 PM

    Hi Atul,

    Could you run a frequency sweep on your setup? By that we could see the actual response of the amplifier. In Figure 5, at G=+1, the gain is rolling off rapidly after 1 GHz. This means that a very small change in frequency is a drastic decrease on the gain. The best way to see this is on a frequency sweep on your current setup.

    The variation on your result and on the table 5 is due to parasitic capacitance present on your board. This greatly contributes on the decreased bandwidth as compared to the defined value in the said table.


    Regards.

    Jino

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