Shenzhen SiSolver Technologies Ltd
This paper analyzes the reasons of inaccurate PCB impedance simulation of the traditional simulator and introduces a novel and cost-effective method for accurate PCB impedance simulation of any specific stack-ups. The new method doesn't need to extract material properties from prototype boards or empirical modified DK from PCB Fabs. The test results show the new method & tool have better precision simulation ability with deviation less than 2.5%, compared with traditional simulation tool. It can meet the requirement of less than 5% tolerance impedance to match the high speed & high frequency PCB design, and consequently leads to a more cost-saving and time-saving method to rapidly occupy the market.
DK distribution of FR4 mixed dielectric is not uniform, and Electromagnetic field distribution of impedance model is not uniform too. Traditional method uses a fixed DK to design, but the real effective DK is multivariable. 10% impedance tolerance is the ultimate limit of the empirical DK method, and it helps only for some simple boards. Empirical DK method results in the Black-Box of impedance design process. The non-transparent Black-Box lead to problems on the quality, cost and lead-time. The introduced new method using the specific stack-up & DK simulation technique and multilayers dielectric field solver with resin-filled layer can achieve <2.5% tolerance. The new method is novel and cost-effective without any empirical data involved. It helps to achieve 5% tolerance spec and save lots of cost and time.
Initially Published in the SMTA Proceedings