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LMH6401: Single ended to differential conversion with no gain and low noise figure

Prodigy 40 points

Replies: 5

Views: 129

Part Number: LMH6401

I need to convert a single ended signal to a differential signal. However, I do not require gain. Additionally, this is a highly sensitive measurement, so low noise figure is critical. The only SE to differential converters I can find are amplifiers with quite a bit of gain. With the gain, I end up having to add attenuation (both before and after amplification), which greatly reduces SNR.

Is there a SE to differential converter with no gain and low noise figure?

  • Hi, 

    I would suggest that you could look at the THS4131 as an option. This has an input referred noise of 1.3nV/rtHz. To figure out the exact noise figure I need to know the impedance of your source. Is it 50 Ohms? 

    Regards, 

    Jacob Freet 
    High Speed Amplifiers

  • In reply to Jacob Freet:

    Hi Jacob,

    Thank you for the great suggestion. I see that the gain is tunable and can be set to 1 if desired. That is exactly what we are looking for.

    I should have given more information in my question though, I apologize.

    We are indeed operating at 50 Ohms. However, the THS4131 unfortunately does not have enough bandwidth. Ours is a broadband application, DC to 6.5 GHz. Sorry for not clarifying that up front. Are there similar components with the bandwidth we need?

    Thanks!

    -Brandon

  • In reply to Brandon Buckley:

    Are you seriously DC to 6.5GHz - that DC part is hard in a 6.5GHz high end - and normally, you need some gain to get a low input noise figure. There are some specialized modules that do that span, but virtually the entire 6.5GHz RF amplifier world is AC coupled. 

    Michael Steffes

  • In reply to Michael Steffes:

    found one, but I am sure there are a few others, 

    https://www.rfmw.com/Products/Detail/MMA053AA-Microsemi-Corp/618501/

    Michael Steffes

  • In reply to Brandon Buckley:

    Hi Brandon, 

    The LMH5401 or LMH6401 are going to be the closest devices we have. 

    Regards, 

    Jacob Freet 
    High Speed Amplifiers