HMC440 Evaluation Board - defect or am I doing something wrong?

Hello,

I am currently working on a project using the HMC440 Evaluation Board. I started working with the board on Monday and it did seem to work then. When I attempted to do some more tests with it on Tuesday I couldn't get it to work at all. The only thing I'm getting from the NU and ND Outputs are constant 3V/5V signals without any pulses. The only thing I'm getting from NFOUT and FOUT is a low voltage(~50mV) signal whose frequency is equal to the CLK input frequency. As for my Setup: Jumpers are installed on S2-S5 and there is no Jumper on S1 (changing jumpers around doesn't change anything tough). I'm using a 5V, 0.45A DC power supply to power the board and an Agilent 33500B Waveform Generator to provide the CLK and REF input signals. I am, for example, using sine waveforms with a frequency of 30MHz(CLK) and 15MHz(REF) with an Amplitude of 1Vpp each which results in ~0dBm. Is there anything wrong with my setup or did I break the chip?

Thanks,

Peter

  • 0
    •  Analog Employees 
    on Mar 3, 2016 4:59 AM

    Hi Peter,

    Can you send along a block diagram of your implementation?

    Be careful loading down the NU/ND ports, as these are intended to drive a high impedance load (diff amplifier).  If these outputs are loaded down below 2.5V, then the internal output transistors can saturate and become damaged.

    Additionally, the FOUT/NFOUT ports should only be used for testing with high impedance scope probes or DC blocks.

    It's best to use square waves for the input frequencies you listed.  The device is edge triggered and needs a good rise time for best performance.  The HMC698 & HMC699 are sister parts to the HMC440, which show examples of the phase noise floor performance variation with respect to input power level and waveform type.  This same performance can be expect of the HMC439, HMC440, HMC3716, and HMC4069.

    Best Regards,

    David

  • Hello David,

    this is how my test setup looked:

    I did try using square waveform signals but I still get no output signal (appart from the 3/5V DC). Is it safe to assume that the HMC440 is defect and do you see what part of my setup may have caused the defect? We already ordered another HMC440 in order to replace the (presumably) broken one so what changes to the setup do you propose so that it doesn't break again? I must add that I have almost no prior experience with RF electronics so please be elaborate with your answers.

    Thanks,

    Peter

  • 0
    •  Analog Employees 
    on Mar 7, 2016 1:54 AM

    Hello Peter,

    Perhaps the unit is kaputt.

    One way to check device functionality is to offset the two frequencies at the PFD by 1kHz.  For example, if N=2 and VCO=100MHz, then REF would be 50.001MHz.  You should see a negative sloping sawtooth waveform at the 1kHz difference frequency on the NU port.  Likewise, if you set REF to 49.999MHz, then the ND port should be active.  There will be very narrow pulses present (at the REF frequency).  Enabling bandwidth limiting on the scope should clean it up.  Voltage swing will be from 5V to 3V.  When a port is inactive it will sit at approximately 5V.

    Also, I should mention that we consider the device ESD class 0 and proper ESD handling protocol should be followed.

    Best Regards,

    David

  • 0
    •  Analog Employees 
    on Aug 2, 2018 3:23 PM
    This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

    Thank you,
    EZ Admin