ADL5205 maximum gain


I received some questions from our customer. The customer tried to simulation of ADL5205 using ADL5205 S-Parameters on ADI WEB site. But he got 20dB for maximum gain. Could you please refer attached file?

The questions are followings,

 - Could you please advise me about the circuit for getting the result of Fig.30 of ADL5205 datasheet?

 - Could you please advise me the setting of port impedance of network analyzer for getting the result of Fig.30 of ADL5205 datasheet?

 - Are there any problem about the schematic for the simulation?

Best regards,


  • Hi Akira,

    Couple things to note, seems the measurement is off by 6dB. So you will have a 3dB hit/loss assuming the input is 100ohms and the output is 200ohms.

    Also, can I please ask if the measurement is being taken on the standard eval brd? The same one shown in the datasheet? If so, there will be loss there too.

    The output series resistors will need some adjusting/changes to get the correct gain, as well as if the input and output baluns are being used in the measurement.

    Get back to me on these questions and I can help work through this.



  • Hi,

    Thank you for your reply.

    The customer doesn't have the eval board. But the customer refer the datasheet for their simulation.

    We can see many 0 ohom and other resistors in the iupit circuit and the output circuit of the eval. board schematic.

    How should we use then for the case of single input and output?

    Best regards,


  • Hi Akira,

    The evaluation board is configured by default for a single-ended (SE) input/output using a balun. Please note on the schematic all reference designators that have "DNI" next to it, means "Do Not Install".

    If you need the instructions for a SE input/output without using a balun. Please let me know and I can give you the configuration for that.

    Hope this helps.



  • Hi Rob,

    Thank you for yoru reply.

    I discussed customer about this issue and he would like to know 2 points

    (1) He would like to know waht circuit was used for measuring Fig.30 of ADL5205 datasheet.

          Was it measured by EVB and single-ended input/output?

    (2) He would like to know the setting of port impedance of network analyzer for getting the result of Fig.30 of ADL5205 datasheet.

          Do you have or get like that information?

    Thanks & Regards,


  • Hi Akira,

    Please see attached test setup.

    The network analyzer is setup for 50ohms on each port.