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HMC773A: Can we swap LO/IF port?

Hello,

Can we use HMC773A by swapping LO/IF port under following condition?

For RX;

  Input RF signal : 18.5GHz, maximum 0dBm

  Input LO signal : 0.5GHz, +13dBm

  IF = 18GHz

For TX;

Input IF signal : 18GHz, maximum 0dBm

Input LO signal : 0.5GHz, +13dBm

RF = 18.5GHz

We understand it is not recommended use and you do not guarantee performance. But, could you please advide us we can do like that use? And what kind of impact to perfomances of HMC773A?

Best regards,

Akira

  • Hello Akira,

    In both cases this probably won't work.

    For the IF port you're exceeding the IF BW of the mixer and most of your signal is going to be reflected back due to poor return loss at 18GHz.

    Same goes for the LO port. 0.5GHz is not in the LO BW. Most of the signal is going to be reflected back due to poor return loss.

    Such poor return loss is probably going to affect the system that you put the mixer in as well.

    Why can't the LO/IF ports be used as recommended? Are you looking at the HMC773A to be put into a board which has already been designed?

    Thanks,

  • HI,

    Thank you for your answer.

    Our customer would like to make frequency sifter, e.g. 18.5GHz to 18GHz and 18GHz to 18.5GHz. And the customer looks a mixer for the purpose. In normal case, we input the LO signal to LO port and getting output signal for IF port for a case of downconvertor. But LO port of HMC773A don't support the frequency of 0.5GHz. On the other hand IF port of HMC773A can support 0.5GHz. So, our customer conceived swapping of IF and LO port. I think passive double-balanced mixer can work under swapping IF port and LO port. Does HMC773A has active circuit or special type of passive DBM?

    Tkanks & Regards,

    Akira

  • Hi Akira-san,

    This is a passive mixer double balanced mixer but the LO and IF cannot be swapped a you mentioned. I suggest putting the 0.5GHz signal in the IF and the 18.5GHz signal in the LO.

    If the customer still wants to use the previous configuration I suggest advising the customer to get an eval board and testing it. We don't test for such conditions as we do not recommend it.

    Thanks,

  • Hi,

    Thank you for your answer. Yes, I'll advise to the customer getting the evaluation board of HMC773A and testing it.

    By the way, according to the customer, he has used HMC412AMS8GE and HMC292LM3C by swapping the ports before. HMC412, HMC292 and HMC773A are passive double balanced mixer. Are there any changes of circuit structure between HMC412, HMC292 and HMC773A?

    Thanks & Regards,

    Akira

  •  

    Hi Akira,

     

    HMC412, HMC292 and HMC773A are passive balanced mixers. To make the parts work properly, all the ports need to be fed within frequency range as data sheet required. Otherwise large portion of signals might be reflected.

     

    By the way, HMC412AMS8GE and HMC292LM3C are not recommended for new designs. A new part can be recommended if needed.

     

    Thanks,

     

     

  • Hi,

    Thank you for you support!

    Thanks & Regards,

    Akira