多層印刷電路板中藉由通孔連通柱傳輸差模信號之訊號完整性設計

Signal Integrity Design for A Transition of Differential Signals by Plated Through-hole Vias in Multilayer PCBs

陳政翔(Zheng-Xiang Chen)

指導教授 ： 薛光華

中原大學/電機資訊學院/電子工程研究所/碩士(2016年)

https://doi.org/10.6840/cycu201600400

摘要

本論文研究在厚層印刷電路板(PCB)中對於時域傳輸波形TDT (Time-Domain Transmission)、TDR (Time-Domain Reflectometry)、頻域波形|Sdd21| (Insertion Loss)、|Sdd11| (Return Loss)與眼圖(Eye Diagram)的影響，首先提出差模訊號連通柱原始結構並說明加入空氣連通柱之抑制概念與抑制問題，因走線會隨著製程與其他需求走在不同層，因此差模訊號連通柱長度以及差模訊號連通柱殘段長度不是固定的，因此本論文先利用差模訊號連通柱結構之各參數變化來觀察主要設計方向，並用幾種模擬軟體與公式相互驗證此方式是精準的，接著提出設計帶線在不同層時，利用差模訊號連通柱加入阻抗匹配空氣連通柱來達到阻抗匹配以及差模訊號連通柱殘段加入高阻抗空氣連通柱來使整體阻抗提高降低分流進而改善訊號完整性。
　　本論文所提出之抑制方案不管對於時域波形、頻域波形及眼圖都有很明顯地改善，適當加入空氣連通柱結構可以有效解決差模傳輸微帶線與差模訊號連通柱之阻抗不連續問題，以及利用基本電路原理使訊號往差模訊號連通柱殘段較少而達到好的訊號完整，最後實際做出來的板子，改善結構也有很好的抑制效果。

關鍵字

差模訊號連通柱殘段；眼圖；通孔連通柱；訊號完整性

並列摘要

This paper studies the impact of PCB on the time-domain transmission (TDT) waveform, Time-Domain Reflectometry (TDR) waveform , Insertion Loss |Sdd21| , Return Loss|Sdd11| and eye diagram. First of all, we propose the original structure of differential-mode signal via, and explain the inhibition concept and inhibition problem by adding air via. Because the wiring is conducted on different levels in accordance with the process and other requirements, the length of differential-mode signal via and via stub are not fixed. Therefore, first of all, this paper uses the change between various parameters of differential-mode signal via to observe the main design direction, and also uses several types of simulation software and formulas to verify that this method is accurate; then, during the wiring design on different levels, impedance is added to the differential-mode signal via to match the air via, in this way to achieve impedance match, and the high-impedance air via is added to the residual segment of differential-mode signal via to improve the overall impedance and reduce shunt, in this way to improve the signal integrity.
　　The inhibition scheme proposed in this paper can significantly improve the time-domain waveform, frequency-domain waveform and Eye Diagram. By properly adding the air via structure, it can effectively solve the impedance inconsistency problem between differential-mode transmission microstrip line and differential-mode signal via. In addition, the basic circuit theory can be used to reduce the length of residual segment of differential-mode signal via and achieve higher signal integrity. Finally, on the actually produced board, the improved structure shows great inhibition effects.

並列關鍵字

differential via stubs；eye diagram；plated through-hole (PTH) vias；signal integrity

參考文獻

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