Can the HMC624A be used down to 10MHz with appropriate AGCx caps?

Using the HMC624A for an application that requires a very wide BW (down to 10MHz, up to 5GHz).

Can the AGCx caps be increased to 10nF, or will this cause other problems / transient damage during turn-on / turn-off?

regards,

L

  • +1
    •  Analog Employees 
    on Nov 3, 2020 10:55 PM 1 month ago

    Hi Laudio, 

    For this application circuit, we used 10 nF capacitors for evaluations down to 1 MHz (3dB cut-off frequency of 1/2π*50ohm*10nF=318kHz). For operation down to 10 MHz, 1nF capacitors could be large enough. If max application frequency is higher than the self-resonant frequency of capacitors, a few standard capacitors different in value can be paralleled or a single special broadband capacitor can be used.

    Thanks, 
    HK.

    PDF

  • Thank you very much for the detailed information - I see that the P0.1dB is greatly reduced <100MHz (and have seen a large increase in the 2nd Harmonic in my testing) - are there any other DSA ICs that I should consider for the 10-5000MHz range instead?

  • This is typical behavior for all GaAs switches or DSA. I had similar problem, I was searching such DSA within AD portfolio, but without success. From my experience good performance have got Peregrine DSA, these DSAs degrade linearity also at lower frequencies, but you can find MPNs from 10MHz up. The control interface can be of course different.

  • Thanks for the suggestion. I had looked at some of those SOI attenuators, but they are a bit slow for my application (in terms of switching speed), or poor return loss.

  • 0
    •  Analog Employees 
    on Nov 9, 2020 10:16 PM 25 days ago in reply to Laudio

    Hi Laudio,

    Have you looked at HMC424ALP3E? The P0.1dB does also degrades at lower frequencies. But does that work for you?

    What is your switching speed and other critical requirements? Could you please provide more details on your application? Please feel free to DM if you would rather chat discuss the applications privately.

    Our recently released UWB Silicon DSAs will work for you: ADRF5720/30, ADRF5721/31, or ADRF5740.
    Please note, these are considerably more expensive than the HMC624A previously being considered.

    Thanks,
    HK.