10 HDI PCB Design Tips to Maintain Signal Integrity

Originally published at: https://www.protoexpress.com/blog/hdi-pcb-design-tips-for-signal-integrity/

When it comes to designing HDI PCBs, a plethora of challenges await, including complex routing requirements, issues related to propagation delays, electromagnetic effects, and impedance mismatches. To fully harness the potential of high-density boards, consider signal integrity to avoid issues like crosstalk and signal reflection. Highlights: To maintain signal integrity: Select a dielectric material with low Dk (<4) and(<4) Df Place the signal layers between the ground planes Place microvias as close as possible to the signal pads to avoid impedance discontinuities Place the decoupling capacitor close to the power pins to ensure power integrity 6 common challenges in designing…

In HDI PCBs, where traces outside the BGA region have a standard width and spacing of around 4 mil, what is considered an acceptable deviation in trace width and spacing when breaking out a BGA? How can you ensure that the transition from the BGA region to the rest of the PCB maintains signal integrity while accommodating the necessary changes in trace characteristics?

What termination techniques do you find the most effective for high-speed signals in HDI PCBs, and how do you determine the appropriate termination method?

Generally I think parallel is the default if you have no information. As far as determining the best method you should go by the components data sheet.

  1. For component ingress and egress the discontinuities should be limited to Lambda/10.

  2. By measuring it, preferably with a VNA.

  3. Follow “Best Practices”