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  1. Is the absolute maximum input for INP still +10dBm if the input is driven single-endedly with INN terminated in 50 ohms?
  2. is the sampling transfer function in the datasheet a plot of the peak amplitude at the output vs the input frequency? with THA+ADC setup, the 3dB bandwidth of the frequency response from ADC was only abt 8GHz. Across the 18GHz, the gain dropped about 5.5dB. what could be the cause?

Thank you.

  • 1. Yes. The Absolute Max listed in the datasheet is per pin, applies to each pin.

    2. Strictly speaking, the sampling transfer function plot applies at the output of the HMC1061 device. However, we also show another plot right next to it on the same page that shows the transfer function of the HMC1061 followed by an ADC. The bandwidth in either case is essentially the same. You should not be seeing it limited to 8 GHz, provided the test is being done correctly.

    It is important to make sure that the HMC1061 input is given a constant 1Vpp differential signal throughout the frequency range. If the driving circuit loses amplitude as the frequency is increased, the signal generator's output power must be adjusted to keep the HMC1061 input amplitude at 1Vpp. Also please note that all specified performance for this device is with differential input signal. Although the device can be operated with single-ended drive, the performance will be affected.


  • Hi,

    1. if the input amplitude is maintained at some lower voltage, will it affect the performance?

    2. I am only using CLKA with CLKB terminated, will this degrade the performance?

    3. May I know how do you generate the differential signal for the HMC1061?

    4. If the device is operated with singel eneded drive, how much is the performace degraded?


  • 1. A lower input amplitude than the specified full-scale will directly subtract from the system SNR. On the other hand, the SFDR with respect to the carrier will improve a little as the carrier power is reduced a little from the full-scale. As the carrier power is further reduced, the SFDR may not improve much more.

    2. Yes. The effect is less than what's seen with single-ended signal input, but there is some degradation.

    3. A wideband balun is the best way to do this unless DC operation is required. In that case, a wideband diff. amp may be used. ADL5566 is one such device you may consider. Its -3dB bandwidth is 4.5GHz. Marki Microwave or Mini-Circuits baluns have worked well for us.

    4. We have not characterized the single-ended operation.

    In fact, for all the above issues, I would recommend thoroughly evaluating the HMC1061 using its eval board in conjunction with the ADC of your choice.



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    EZ Admin