PCB News - Circuit board factory: Is the PCB design wiring must not go at a 90 degree right angle?

Circuit board factory: Is the PCB design wiring must not go at a 90 degree right angle?

Circuit board factory: "PCB design should avoid right-angle routing", most PCB engineers know this requirement. So, must the PCB design traces not go at a 90-degree right angle? To answer this question, we must first understand the effect of 90° right-angle wiring on the signal. The influence of 90° right-angle wiring on the signal is mainly reflected in three aspects:

  1, the right angle can be equivalent to the capacitive load on the transmission line, slowing down the rise time;

  2, impedance discontinuity will cause signal reflection;

  3, EMI generated by the right-angle tip.

The reason why 90° right-angled traces can cause signal integrity problems is that the width of the copper foil at the right-angle corners of the transmission line is wider than that of straight-line traces, which will cause a sudden change in the characteristic impedance at the right-angle bend; Ordinary signal routing will not cause problems, but for high-speed transmission lines, signal reflections will occur, and serious reflections will cause signal integrity problems. Therefore, when designing high-speed circuit boards, routing through the 45° corner mode instead of 90° cornering can reduce the signal reflection caused by the change in wiring width and the signal rise delay caused by this additional discrete capacitance. Change.

In addition, many people think that the right-angled tip is easy to transmit or receive electromagnetic waves and generate EMI. This has also become one of the reasons why many people think that right-angled wiring cannot be routed.

In general, it is recommended that when doing PCB Layout, right angles are prohibited, whether it is ordinary signal lines, high-speed digital signal transmission lines, or RF transmission lines, including copper-clad copper, all are designed to be obtuse angles.

The above is the interpretation of the question "Is the PCB design trace must not go at a 90 degree right angle?" I hope it will be helpful to you. iPCB is a high-tech manufacturing enterprise focusing on the development and production of high-precision PCBs. iPCB is happy to be your business partner. Our business goal is to become the most professional prototyping PCB manufacturer in the world. Mainly focus on microwave high frequency PCB, high frequency mixed pressure, ultra-high multi-layer IC testing, from 1+ to 6+ HDI, Anylayer HDI, IC Substrate, IC test board, rigid flexible PCB, ordinary multi-layer FR4 PCB, etc. Products are widely used in industry 4.0, communications, industrial control, digital, power, computers, automobiles, medical, aerospace, instrumentation, Internet of Things and other fields.