Suggestions on High-speed PCB Design of Holes
Gold Phoenix PCB Co., Ltd was founded in 2000 and is the one of the most complete large-scale OEM/ODM Manufacturer in Wuhan, whose specialty is engaged in PCB design, PCB layout, PCB fabrication and PCB assembly. The company employs over 200 highly skilled people and provides the highest in quality products.
In high-speed multilayer circuit, growing data rate make signal integrity become a critical design issue which greatly affect the overall performance of a high-speed circuit. As a result, the PCB design of the throng-hole, a PCB electrical conductors used to connect the routing in different layers, is very important. The throng-hole is comprised of hole, the solder pad around and POWER layer quarantine and is usually divided into blind hole, buried hole and through hole. In high-speed PCB design, the simple holes will cause a great deal of negative effects to the design of the circuit, especially in the high-speed multilayer. Due to the frequency growth and the steepening of the signal rising edge, the impedance discontinuities caused by holes will bring about signal reflection which seriously impact on the system performance and signal integrity.
In order to reduce the adverse effects of hole parasitic, here are some suggestions on the PCB design service. Firstly, in view of both the cost and signal quality, a reasonable size of the hole is very important. At present, it is difficult to make the hole much smaller. On the other hand, holes with a larger size for power supply or ground wire is also necessary because of the impedance reduction. Secondly, thinner PCB board is conducive to cutting down two of the parasitic parameters of the holes. Thirdly, the holes of the PCB board signal traces should be as few as possible .Fourthly, the holes for power and ground pins should be as near as possible to make sure the lead between the holes and pins as short as possible in order to avoid the increase of inductance. Meanwhile, power and ground leads should be as thick as possible to reduce the impedance. Fifthly, some ground holes could be placed near the holes for the signal changed in different layers in order to provide the nearest loop for the signal. Even a great amount of extra ground holes can be placed on the PCB. But in the case of great hole density, some solder pads may lead to the formation of breaker slot in copper layers to cut off the circuit, the solution is to move the hole location or cut down the pad size of the holes in this copper layer.
These days, the high-speed PCB design is widely used in the field of communications, computer, graphics and image processing and so on. The design of all of the high-tech value-added electronic products is in the pursuit of low power consumption, low electromagnetic radiation, high reliability, miniaturization, etc. in the high-speed PCB design. In order to achieve the above objectives, the PCB design of holes is an important factor. Gold Phoenix will keep on improving the technology and offer better PCB design service.