EVAL-ADL5391 single-end input

I like to input 2.5V ±1V sine wave whose frequency range is between 1k - 10kHz.

I wonder if I can use EVAL-ADL5391 X input configurations at datasheet figure23.

Judging from Table4 descriptions, I can remove T1 and replace it with 0Ω resistor.

Can I use X input without T1 for my usage?

what is the original purpose of T1?

what is the waveforms at XPLS and XMNS terminals when remove t1?  2.5V +/-1V sine wave and 2.5V -/+1V sine wave?

Is R1(56.2Ω) needed for my purpose?

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  • 0
    •  Analog Employees 
    on Aug 19, 2021 3:37 PM

    HI -

    The input to ADL5391 can be single ended, differential or through a Balun.

    One thing to note is that the frequency range and dynamic range will be limited if used as a SE mode.

    The original purpose of T1 is for Single-ended-to-differential transformation for high frequency ac
    operation. If you are planning to do dc operation then the T1 balun can be removed and jumped over using 0 Ω resistors.

    The evaluation board is matched for lower frequency operation, so I think you should be okay for your frequency range operation up to 10KHz.

    If you are driving the X inputs SE, without ac coupling capacitors, the reference voltage of 2.5 V needs to be taken into account. Voltages above 2.5 V are positive voltages and voltages below 2.5 V are negative voltages.

    As C1 (DC blocking Cap) is not installed on the EVAL board on XMNS terminal there is no waveform at this terminal.

    With regard to the R1 resistor(56.2ohms) its a matching resistor. The fundamental bleed through not only depends on the amount of
    power put into the device but also depends on matching the unused differential input/output to the same impedance as the
    used input/output.

    So it is good to keep it installed for your purpose, especially if you are not using the Y and Z inputs.

    To be able to assist you better, can you please answer the following Qs.

    1.Are you planning to drive 5391 in SE operation on all the  inputs and outputs.

    2.  Or Are you planning to use 5391 SE on X inputs alone?

    3. What do you plan to apply on the Y inputs- YMNS & YPLS & the summing input Z?

    Any details on your application would be helpful?

    Warm Regards,

    Rachana

  • >1.Are you planning to drive 5391 in SE operation on all the  inputs and outputs.

    >2.  Or Are you planning to use 5391 SE on X inputs alone?

    >3. What do you plan to apply on the Y inputs- YMNS & YPLS & the summing input Z?

    I plan to use Figure22 circuit configuration after removing T2 and T3. I don't input to Z.

    In this case, does the circuit work well in the frequency range between 1k and 10kHz?

    what are input voltage ranges to XPLS and YPLS?

    Does the bleed through get problem in this circuit configuration? and in what condition does the bleed through get problem?

  • 0
    •  Analog Employees 
    on Aug 26, 2021 6:18 PM in reply to ogura.isao@sankyosha.co.jp

    Hi,

    So are you planning to use ADL5391 as a square law detector?.. DO you plan to drive 5391 as a SE input for DC operation or with using ac-coupled caps.

    Can you please share details of your application, so we can  assist you better?

    if you remove T2 & T3, do you plan to drive the part with differential inputs?.. After removing T2 & T3, do you plan to put 0 Ohms in its place?

    The impedance matching provided by R1 & R2 should be good for low frequency operation. So I believe your frequency range should be supported with fig 22.

    The input voltage ranges for XPLS and YPLS is VPOS, as listed under the Absolute Max Ratings Table #2 on Page 5 of the DS.

    In the Fig 22 configuration the bleed through is not a problem, during the amplitude squaring application, there are components of the multiplier output that correlate to the signal bleedthrough and second harmonic.

    As mentioned on Page 11 of the DS, The fundamental bleed through depends on the amount of power put into the device and matching the unused differential input/output to the same impedance as the used input/output.

    from equation 4 on the page 11 of the DS, the input signal bleedthrough depends on the internal offset of the circuit and input signal amplitude.

    Warm Regards,

    Rachana

  • I plan to drive 5391 as SEs with ac-coupling caps like Figure22 replacing baluns with 0 ohms in places.

    I like to know if my configuration circuit works with R1, R2 resistors for low frequency like 1kHz.

    Or Do I need to remove R1, R2?

  • +1
    •  Analog Employees 
    on Aug 31, 2021 12:40 PM in reply to ogura.isao@sankyosha.co.jp

    Yes your mentioned  configuration circuit works with replacing baluns with 0ohms.

    You will need the R1 & R2 resistors in the circuit. These provide impedance matching for low frequency operation at like 1KHz.

    Warm Regards,

    Rachana

  • 0
    •  Analog Employees 
    on Sep 14, 2021 3:28 PM in reply to rachana.kaza@analog.com

    HI - Please let me know if you need any further information on this.

    Thank you,

    Rachana

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