• HMC492 failures

    I've created a microwave counter using an HMC679 chip followed by 4 HMC492 chips, driving more ( common ) ECL chips.

    Initial tests showed all the HMC492 chips were failed and had to be replaced. I attributed this to the soldering process ( oven reflow…

  • RE: HMC573 HMC492 HMC905

    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,
  • RE: HMC492 bistable behavior


    It sounds like the divider is self oscillating when the input is removed.  There is an app note on this phenomenon at the link below.  The appropriate value to prevent self oscillation without RF input is 8.25k for the HMC492, HMC493, and HMC494.

  • RE: HMC-493 and HMC-492 self oscillation

    Hi Eric,

    In the past we have found that 8.25k was the appropriate value to prevent self oscillation without RF input for the HMC492, HMC493, and HMC494.

    Best Regards,


  • how to calculate the Active loop filter parameter when I use HMC702 and HMC733 with HMC492 to generate a signal of 16GHz? In my design,the PFD is 60MHz with the reference frequency 120MHz.Must I change the Kv of the VCO when I use the Hittite PLL  ev...

    使用HMC733和HMC702和分频器HMC492产生16GHz的信号,参考频率 120MHz,鉴相频率60MHz。我计算环路参数的时候需要将Kv除以2吗?因为VCO输出的频率经过功分和分频之后返回到HMC702的VCOIN端。

  • RE: Can I use the chip of HMC492LP3 to get a 5G sine wave while giving a input of 10G sine wave ?


    The HMC492 frequency divider output will be a square wave with strong odd harmonics.  If you wish, you can low pass or band pass filter the output to achieve a sine wave.

    Generally speaking, most frequency dividers/counters are edge triggered logic…

  • RE: HMC494LP3 self oscillation

    Hi there,

    Some dividers will self-oscillate in the absence of an RF input signal. For the HMC492, 493 and 494 dividers a shunt 8.25k ohm resistor placed on one of the differential inputs was the appropriate value to prevent self oscillation.


  • RE: 关于在二分频器HMC492LP3芯片手册中的问题


  • Equivalent Hours of HMC764LP6CE & HMC783LP6CE

    Dir Sir,

    I would like to know the equivalent hours of HMC764LP6CE & HMC783LP6CE. I cnn't find the information in the attached Reliability Report. How can I calculate that value?

    Best regards,


  • RE: HMC394LP4, CML Interfacing to Inputs

    Some of the other HMC dividers have an input network similar to what you described (as an example HMC705 or HMC492), but this part went a different route for some reason.  I also would tend to agree with you the /IN naming convention.

    In regards to the diagram…