Again, a perfect supply voltage decoupling must sit at driver of stripline. Nevertheless, as power supply planes do always show much higher noise than ground planes, using a power plane as reference layer cannot be suggested. In not so much demanding applications this can be done, but with your application it seems not to be a good idea.


You cannot avoid this discontinuity, only reduce it a bit. Try to use a few vias in parallel to reduce the effective inductance. Do always use vias for the reference layers surrounding the stripline too, like Richard has recommended it.

Mike, discontinuities introduced by vias do only play a serious role to my experience, when you have many layer changes.

Do you have the right formulas for the striplines? Take care, when routing the stripline near the edges of board, the stripline impedance can relevantly change! For the wave packet to travel properly along the stripline you need uncorrupted reference planes next to the stripline for at least 2cm. When routing the stripline next to the edges or when making steep 90° "curves" discontinuites can come into play, which can result in echoing and ringing, not even mentioning the change of stripline impedance they introduce. So, make only soft curves and keep away from the edges of board and from other striplines also running in this layer!

It's always a good idea to slow down the slew rates and smooth the edges of signals if high slew rates and steep egdes are not needed. In this case use a suited low pass filter at the output of driver. Also, the use of a proper stripline is no longer needed then.

Try to use symmetrical signal routing whenever possible! This will heaviliy minimize the induced ground noise in the reference planes, because the reference planes are no longer the path for the ground return currents! At the same time the susceptibility of stripline signal against noise in the reference planes is minimized too!

Kai