You can tell when something isn’t as clear as it should be. The same questions come up time and again. You ask three experts and get three different answers. Routing differential pairs can be like that. Why? Because “it depends” – on exactly what signals those pairs are carrying and what kind of PCB you’re creating.
Do you still use Post-it Notes? Invented in 1979, this simple, yet incredibly powerful, communication mechanism is still commonly found in engineering and design departments. Despite modern electronic communication, many companies still struggle to provide a replacement for their ease-of-use and versatility.
This post is dedicated to the PCB designer who logs hundreds of hours each year manually routing complex PCB designs while wishing the activity was not so detailed and stressful.
As Zuken technology partners, we are often asked about how best to set PCB constraints for double-data-rate (DDR) memory, and how to route to those constraints. This question arose recently when we were asked to create a common style of DDR3 design for training, and we tried mining the web for detailed information on PCB constraints. There had to be something out there, we thought.
Recently, a discussion flared up in our office after someone questioned the use of the term ‘trunk routing’. They wondered whether it’s really a term in its own right – or just a fancy name for bus routing? The question was raised by someone who’s not that familiar with our high-speed design tools – so we’ll let them off the hook! But it begs the question: do people really understand the difference between the two?