邊緣耦合差分對(duì)稱(chēng)帶狀線(xiàn)傳輸線(xiàn)是一種常見(jiàn)的差分走線(xiàn)布線(xiàn)技術(shù)。有四種不同類(lèi)型的阻抗用于表征差分走線(xiàn)阻抗。這個(gè)計(jì)算器可以找到奇數(shù)和偶數(shù)傳輸線(xiàn)阻抗。建模近似可用于了解邊緣耦合差分帶狀線(xiàn)傳輸線(xiàn)的阻抗。

The edge couple differential symmetric stripline transmission line is a common technique for routing differential traces. There are four different types of impedance used in characterizing differential trace impedances. This calculator finds both odd and even transmission line impedance. Modeling approximation can be used to understand the impedance of the edge couple differential stripline transmission line.

邊緣耦合差分對(duì)稱(chēng)帶狀線(xiàn)傳輸線(xiàn)由兩條跡線(xiàn)構(gòu)成，兩條跡線(xiàn)參考跡線(xiàn)上方和下方的相同參考平面。它們之間有介電材料。線(xiàn)路之間也存在一些耦合。這種耦合是差分走線(xiàn)的特征之一。通常，匹配差分走線(xiàn)長(zhǎng)度并保持走線(xiàn)之間的距離一致是一種很好的做法。還要避免在這些走線(xiàn)之間放置過(guò)孔和其他結(jié)構(gòu)。

An edge couple differential symmetric stripline transmission line is constructed with two traces referenced to the same reference planes above and below the traces. There is a dielectric material between them. There is also some coupling between the lines. This coupling is one of the features of differential traces. Usually it is good practice to match differential trace length and to keep the distances between the traces consistent. Also avoid placing vias and other structures between these traces.

差分阻抗定義 Differential Impedance Definitions

差分阻抗 當(dāng)兩條線(xiàn)用相反極性的信號(hào)驅(qū)動(dòng)時(shí)測(cè)量的阻抗。Zdiff 等于 Zodd 值的兩倍

奇阻抗 僅測(cè)試一條以接地層為參考的差分走線(xiàn)時(shí)測(cè)量的阻抗。差分信號(hào)需要用相反極性的信號(hào)驅(qū)動(dòng)。Zodd 等于 Zdiff 值的一半

Common Impedance 用相同信號(hào)驅(qū)動(dòng)兩條線(xiàn)路時(shí)測(cè)量的阻抗。Zcommon 是 Zeven 價(jià)值的一半

偶阻抗 僅測(cè)試一條以接地層為參考的差分走線(xiàn)時(shí)測(cè)得的阻抗。差分信號(hào)需要用相同的相同信號(hào)驅(qū)動(dòng)。Zeven 是 Zcommon 價(jià)值的兩倍

Differential Impedance The impedance measured between the two lines when they are driven with opposite polarity signals. Zdiff is equal to twice the value of Zodd

Odd Impedance The impedance measured when testing only one of the differential traces referenced to the ground plane. The differential signals need to be driven with opposite polarity signals. Zodd is equal to half of the value of Zdiff

Common Impedance The impedance measured between the two lines when they are driven with the same signal. Zcommon is half the value of Zeven

Even Impedance The impedance measured when testing only one of the differential traces referenced to the ground plane. The differential signals need to be driven with the same identical signal. Zeven is twice the value of Zcommon

微帶傳輸線(xiàn)模型 Microstrip Transmission Line Models

已創(chuàng)建模型來(lái)近似微帶傳輸線(xiàn)的特性。Models have been created to approximate the characteristics of the microstrip transmission line.

  for (s/t) >= 5

  for (s/t) < 5

Impedance calculation

Edge coupled microstrip impedances (Z_0,odd, Z_0,even, Z_0,diff and Z_0,common) shall be calculated as specified in previous paragraph.

Example 1

Inputs
T = 1.2 mil
H = 63 mil
W = 10 mil
S = 63 mil
ε_r = 4

Output
Z_odd = 78.4 Ω
Z_even = 78.3 Ω
Z_diff = 157 Ω
Z_common = 39.2 Ω

Example 2

Inputs
T = 1.5 mil
H = 70 mil
W = 15 mil
S = 65 mil
ε_r = 4.3

Output
Z_odd = 68.1 Ω
Z_even = 68.0 Ω
Z_diff = 136 Ω
Z_common = 34.0 Ω

Reference

[1] IPC-2141A “Design Guide for High-Speed Controlled Impedance Circuit Boards”