I am planning to use HMC252 in my new project which is based on RF - UHF band. I need detailed layout guideline and PCB stack up guideline for this device.

Few basic questions :

  1. Does it require specific laminate for PCB stackup or any laminate can be used? Can I use standard FR4 material?
  2. How much long I can route the RF signal to and from switch? Longer traces prone to radiate if length is more than quarter wavelength.


pavan vora

  • Hi,

    I attached the mfg files of HMC252QS24E Evaluation board. It is constructed of four layer stack-up used in most of our product evaluation boards. The top dielectric layer containing the RF transmission lines is 10-mil RO4350 with dielectric constant of 3.48. RF transmission lines are designed using a coplanar waveguide with ground plane model and having a characteristic impedance of 50 Ohm with a trace width of 16mils, and clearance to ground plane of 13mils.

    You can use FR4 dielectric material instead of Rogers on the basis of your preference. FR4 will give you a decent electrical performance at the operating frequency range of HMC252QS24E if you follow the general layout techniques of RF PCB design.

    I recommend you to keep RF transmission lines as short as possible. As you said longer traces are more susceptible to EMI and also increases the path loss.


  • Thanks s.ilke

    Here, specific to my application, I need to rout signal longer than 2 inch. Do you see issues routing signals with much of length? Will it work properly if I follow proper impedance control requirement?

    Can you provide me some more info for generic RF layout guidelines as I am new to RF world? A link to the source will also be enough.



  • Hi,

    I suggest you to search "RF PCB design techniques" on the web. You will find many good resources.


  • We used HMC252 in one of our Bluetooth application, at first the HMC252 works fine, but later on 1 out of the 6 channels is broken (very high DC impedance while the control pins are set correctly). We then replaced the HMC252 with a new chip, that channel was then back to normal. This phenomenon has occurred in three HMC252s.

    Has anyone seen this before? and how to solve it? we can't keep replacing the chips...


  • 0
    •  Analog Employees 
    on Aug 12, 2015 5:51 PM

    Duplicate question. Please reply here: