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LMH6552: TINA simulation

Samaneh Afshar
Intellectual 330 points
Part Number: LMH6552
Other Parts Discussed in Thread: LMH5401

Hi, 

 I need to deliver a single ended signal with 2.8 VPP amplitude to 1 50 ohm load. The frequency of the signal is ranging between 100 to 700 MHz. I have decided to go with LMH6552 as it has a bandwidth of 1.5 GHz with voltage swing of 10 V. I have designed the LMH6552 for gain of 5V/V. I have attached my TINA file. Could you please let me know why for frequencies above 200 MHz the output signal is not sinusoidal anymore?

Please kindly note  that I can provide either differential or single ended signal to the LMH6552 but the output should be single ended.So I appreciate if you let me know if there exist any better TI product for this application.

Regards

SamanehLMH6552.TSC

  • 0
    TI__Genius 15565 points

    Hello Samaneh,

    You are reaching the slew rate limitation of the part. At 3800 V/us with a voltage swing of 10Vpp, you will begin to push the slew rate at around 190MHz.

    Best,

    Hasan Babiker

  • 0
    Guru 48395 points

    Why are you using an FDA if you need single ended out - FDA's typically will have poor HD2 on each side, cancelled by using differential. 

    700MHz 2.8Vpp requires a min SR of 6000V/usec - look for parts with more than that to have any hope. 

  • 0 in reply to Michael Steffes
    TI__Genius 15565 points

    Hello Samaneh,

    You may want to use the LMH5401 in a single-to-differential conversion and then using a balun for diff to a single-ended output.You can use a balun at the output here since the frequency requirement is from 100 to 700MHz. The device can do close to 2.8Vpp for 150-ohm single-ended output.

    The LMH5401 can also be used here without the balun at its output, but the HD2 distortion will be worse as Michael as pointed out.

     The schematic will be something similar to the below, only that the balun will need to be a 1:1 from Mini-circuits or Macom:

    Best,

    Hasan Babiker