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Get Up To Par With Signal Integrity

In this day and age, signal integrity for a high-speed PCB design takes on new meanings. The PCB designer cannot be complacent with the same procedures and rules of thumb practiced before. These days, he or she must be at the top of their game when it comes to assuring signal integrity. Take for example if digital high-speed signals aren’t correctly routed, they can cause jitter or worst case, a device’s complete malfunction.

figure1-PlacementofDecouplingcapacitors (1)Also, analog devices with low-end amplitude analog signals take on special consideration and attention. Those signals are extremely prone to noise. If digital noise seeps into them from the planar capacitance located between digital and analog planes, those analog devices won’t function properly.

You should take a moment to check out our article on signal integrity appearing in PCD&F/Circuits Assembly Magazine, a leading industry publication. This article gives you a clear picture of the areas to focus on when it comes to signal integrity.

In the meantime, here are some tips and hints to know about signal integrity.

  • Find out how detailed the PCB layout engineer is checking out the board’s schematics. This is crucial data that cannot be overlooked.
  • Ask about how component placement is being performed. What steps are taken to isolate the critical areas on the board?
  • Get a better handle on the stack up of your PCB. There are a number of key factors making it an effective stack up. Learn about those.
  • Assure that decoupling capacitors are properly placed on the opposite side of the BGA right below the pin, as shown in Fig. 1 above.
  • Learn how experienced the PCB layout engineer is. Experience pays handsome dividends especially for trace routing.
  • Check on how power supplies are dealt with. Is the PCB layout engineer precisely following the manufacturer’s guidelines?

Signal integrity demands considerable attention these days due to the increasing complexity of PCB designs and the highly advanced digital and analog components OEM system houses require. There are countless areas a PCB layout engineer can overlook, thus creating signal integrity issues. So, it’s always a good idea to encourage your contract manufacturer or EMS Provider to provide you the most experienced and savvy PCB layout engineer. This is the professional who is adept at carefully evaluating certain considerations and taking the necessary actions to maintain PCB signal integrity.