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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?


IF Frequency = 2650MHz

LO Frequency = 2875MHz to 3162MHz

RF Frequency = 225MHz to 512MHz



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. 



  • Hi Keddy,

    I believe your question is directed at the AD8342. 

    I support the LTC6948.  I just wanted to make sure your customer was aware of the LTC6948's frequency gap between the output divider = 1 and output divider =2.  Based on their LO frequencies they could head a couple routes

    1) LTC6948-4 could support both Down and UP conversion LO frequencies

    2) LTC6948-1 for Down conversion, LTC6948-2 for UP conversion

    Performance should be similar with either approach.  I just wanted to make sure they notice frequency gap and order the correct LTC6948 version for each path. 



  • Hi Chris,

    Thanks for your reply! 

    My question is at AD8342. However, your reminding do prompt me for double checking with my customer. Thank you very much!

    BTW, do you know who can advise me on the AD8342?


    Keddy Yang

  • Looks like we found the AD8432 eng.  Had an error in the system.  Should see something shortly.

  • 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.

  • This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

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    EZ Admin