Use AD8342 for Tx and Rx path

Hi there,

My customer is using LTC6948 synthesizer with integrated VCO. And intend to use AD8342 for both the TX and RX path if possible. However, using AD8342 on the TX path will require the use of a balun at 225MHz to 512MHz (usually winding type), which is not desirable due to high limitation.  no issue with RX path because at 2313MHz, my customer can easily find ceramics balun.

So back to Tx path, If my customer were to short one end of the differential output to ground without the use of a balun, can you advice what is the conversion gain (or probably a loss by doing so) and any other impact?

Down-conversion

IF Frequency = 2650MHz

LO Frequency = 2875MHz to 3162MHz

RF Frequency = 225MHz to 512MHz

 

Up-conversion

IF Frequency = 225MHz to 512MHz

LO Frequency = 1801MHz to 2088MHz

RF Frequency = 2313MHz

I did recommended LT5560, but my customer concerned about the IIP3 for this part is rather low. 

BR,

Keddy

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  • 0
    •  Analog Employees 
    on May 15, 2018 5:54 PM over 2 years ago

    Here is the answer from the AD8432 engineer

    We don’t have single ended data for this part. There will be obvious performance degradation, such as gain, linearity, spur level, if one port is grounded directly. There is one section IF port in AD8342 datasheet talking about how to design the load circuitry, page 17-18. There are three ways, using buffer amplifier, balun or impedance matching network. Customer can use any of them and follow the instructions to design their own circuit.

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  • 0
    •  Analog Employees 
    on May 15, 2018 5:54 PM over 2 years ago

    Here is the answer from the AD8432 engineer

    We don’t have single ended data for this part. There will be obvious performance degradation, such as gain, linearity, spur level, if one port is grounded directly. There is one section IF port in AD8342 datasheet talking about how to design the load circuitry, page 17-18. There are three ways, using buffer amplifier, balun or impedance matching network. Customer can use any of them and follow the instructions to design their own circuit.

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