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adjust the gain to 0 dB

Category: Hardware
Product Number: ADL5565-EVALZ, ADL5565

can someone confirm with us to get a a 15.5 dB gain on this ADL5565-EVALZ devboard.

I put zero Ohms for R3,4,5,6 and let R1 and R2 open but I did not get 15.5 Db gain. am I missing any thing or the datasheet is wrong.

Thank you.

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  • Hi  ,

    Good day. Have you tried configuring the other components as stated in Table 18 of the datasheet?

    Based on what you've posted, I think your configuration is correct.

    May we know what your input is and how much gain did you measure? Can you also perform the continuity test on the resistance for check?

    Regards,
    Gilbeys

  • Thank you for the info. Now  we need to get a 0 dB gain for a differential configuration, could please tell us what resistors and with what values to use:

  • Hi  ,


    Good day. The formula of the differential gain of ADL5565 is given by the formula:

    RL is recommended to be 200 ohms but can vary depending on your application. Based on this, we can derive the value of RG to be:

    ^{R_G=\frac{200}{Av}\times\frac{R_L}{10+R_L}}

    From this equation, to get a gain of 1 (0 dB), the recommended value of Rwill be 190.5 or 191 ohms. Since VIP1/VIN1 had an internal resistor of 100 ohms then the recommended external resistor will be 91 ohms. Also, if you are to use VIP2/VIN2, I recommend using an external resistor of 141 ohms. RG is the gain-setting resistor.

    However, it would be better if follow this configuration in the "Gain Adjustment And Interfacing" section of the datasheet:

    With the following resistor values:

    Hope this helps.

    Regards,
    Gilbeys

Reply
  • Hi  ,


    Good day. The formula of the differential gain of ADL5565 is given by the formula:

    RL is recommended to be 200 ohms but can vary depending on your application. Based on this, we can derive the value of RG to be:

    ^{R_G=\frac{200}{Av}\times\frac{R_L}{10+R_L}}

    From this equation, to get a gain of 1 (0 dB), the recommended value of Rwill be 190.5 or 191 ohms. Since VIP1/VIN1 had an internal resistor of 100 ohms then the recommended external resistor will be 91 ohms. Also, if you are to use VIP2/VIN2, I recommend using an external resistor of 141 ohms. RG is the gain-setting resistor.

    However, it would be better if follow this configuration in the "Gain Adjustment And Interfacing" section of the datasheet:

    With the following resistor values:

    Hope this helps.

    Regards,
    Gilbeys

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