There is a “chamfering rule” for PCB wiring, that is, sharp angles and right angles should be avoided in PCB design, and it can be said that this has become one of the standards to measure the quality of wiring, so why not go right angles for PCB wiring?

There are three main effects of right-angle movement on signals:

1. It can be equivalent to capacitive load on the transmission line and slow down the rise time.

2. Impedance discontinuity will cause signal reflection.

3. EMI generated by right Angle tip.

In principle, PCB wiring is acute Angle, right Angle line will make the line width of the transmission line change, resulting in impedance discontinuity, impedance discontinuity will reflect. According to the amplitude and delay of reflection, superimpose on the original pulse waveform to obtain the waveform, resulting in impedance mismatches and poor signal integrity.

Because there are connections, device pins, wire width variations, wire bends, and holes, the resistance will have to change, so there will be reflections.

Right-angle alignment is not necessarily undesirable, but it should be avoided if possible, because attention to detail is essential to every good engineer. And now the digital circuit is developing rapidly, the signal frequency to be processed in the future will slowly increase, these right angles may become the focus of the problem.