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LMH6401EVM: devices with correct impedance that were suitable at 10 MHz - 2.5 GHz

Part Number: LMH6401EVM
Other Parts Discussed in Thread: LMH6401, THS4302

We have an electrical signal (male SMA connector, 50 Ohms) at 10 MHz - 2.5 GHz that we want to be amplified by a LMH6401EVM, which has performance up to 4.5 GHz. According to Fig. 2 of the user manual for the LMH6401EVM, we need two external baluns at the input and output of the LMV6401EVM to convert the input to and output from balanced in order for the LMH6401 to amplify properly.


We were unable to find any such devices with correct impedance that were suitable at 10 MHz - 2.5 GHz and were wondering if you had any suggestions as to what works with your board. A sample setup, as shown in Fig. 2, recommends either a ZFSCJ-2-1-S+, but that device only goes up to 500 MHz; or a BAL-0010, the total (2x) of which costs 10x more than the LMH6401EVM itself and has limited availability / lead time. Thanks...

  • Hi Naser,

    You could eliminate the input balun by grounding one input and applying the signal to the other, but this will only allow you to use half of the output swing.
    Besides using expensive RF baluns, there is not really a better way to use a differential amplifier for a single ended signal. It would be cheaper to use a single ended amplifier like the 2.4GHz THS4302 (5V/V). For RF, it is really only possible to make amplifiers with integrated feedback due to parasitic effects, and we don't have any 2.5GHz variable gain amplifiers currently.

    Best regards,