Simulation design method for AC coupling capacitor reference plane

Abstract

The invention discloses a simulation design method for an AC coupling capacitor reference plane. The method comprises the steps of S1, establishing a PCB model, wherein a hole digging size of an impedance hole is gradually increased by 2mil from a size equal to that of a pad, until the lower side of a capacitor is integrally hollowed; S2, extracting a PCB S parameter through utilization of Sigrity Power SI, importing the S parameter into Hspice for TDR impedance simulation, thereby obtaining a TDR impedance simulation curve and the TDR impedance simulation curve at the position of the capacitor; S3, extracting the impedance at the position of 470ps, obtaining impedance values corresponding to 7 cases and drawing an impedance change curve; and S4, analyzing a simulation result. The method has the beneficial effects that 1, through comparison of various elliptical hole digging modes, a hole digging area with the best impedance continuity effect is found, the impedance continuity of a link is ensured, thereby achieving a signal completeness purpose; and 2, the elliptical hole digging size is researched, thereby obtaining the best hoe digging area, the method is high in operability, is easy to realize in design and production and can be widely applied to the field of high-speed PCB design.

Description

technical field [0001] The invention relates to the field of high-speed PCB design, in particular to a simulation design method of an AC coupling capacitor reference plane. Background technique [0002] In today's era, Internet technology is developing rapidly, and information technology is changing rapidly every day. With the advent of the cloud era and the era of big data, the amount of network data has increased explosively. The transmission of massive data not only poses a test for network transmission equipment, but also for High-speed signal transmission rate puts forward higher requirements. [0003] As data rates increase, small impedance discontinuities on high-speed serial links can cause signal reflections, crosstalk, mode switching, and other adverse effects. There are usually AC coupling capacitors connected in series on the SERDES serial signal differential link to filter out the DC component of the high-speed signal. The ideal coupling capacitor will complet...

AI Technical Summary

Problems solved by technology

The ideal coupling capacitor will completely filter out the DC component of the signal, but in actual circuit work, the capacitor has parasitic inductance. Each capacitor itself, the fan-out leads of the capacitor, and the layer-changing vias are impedance discontinuous point

[0004] Impedance mismatch will bring reflections, affecting the insertion loss (IL), return loss (RL), jitter (Jitter) and bit error rate (BER) of the entire signal link, and ultimately affect the performance of the entire link

Images