PCB科技 - 電路板工廠：阻抗控制對PCB電路板的重要性

電路板工廠：阻抗控制對PCB電路板的重要性

阻抗的含義是什麼 PCB電路板, 為什麼是 PCB電路板阻抗? This article first introduces what 阻抗 and impedance types are. 其次, 它介紹了 PCB電路板 應為阻抗. 最後, 它解釋了阻抗對 PCB電路板. Follow the electronic (電路板廠) editor to learn more about it.

在有電阻的電路中, 電感, 和電容, 交流的障礙叫做阻抗. 阻抗通常用Z表示, 這是一個複數. 真正的部分叫做阻力, 虛部叫做電抗. 電路中電容對交流電的阻礙作用稱為電容電抗, 電路中電感對交流電的阻礙作用稱為電感電抗, 電路中電容和電感對交流電的阻礙作用統稱為電抗. 阻抗組織為歐姆.

(1) Characteristic impedance

In electronic information products such as computers and wireless communications, the energy transmitted in the PCB circuit is a square wave signal (square wave signal, called pulse) composed of voltage and time, 它遇到的電阻叫做特性阻抗.

(2.) Odd Mode Impedance

The impedance value of one line to the ground of the two lines is the same as the impedance value of the two lines.

(3.) Differential impedance

Two identical signal waveforms with opposite polarities are input at the driving end, 分別由兩條差分線路傳輸, 兩個差分訊號在接收端相减. 差分阻抗是兩條導線之間的阻抗Zdiff.

4. Even mode impedance

The drive terminal inputs two identical signal waveforms with the same polarity, 以及兩條導線連接在一起時的阻抗Zcom.

(5) Common mode impedance

The impedance Zoe of one line to the ground of the two lines, 兩條線路的阻抗值相同, 通常大於奇數模阻抗.

PCB電路板 阻抗是指電阻和電抗的參數, 阻礙交流. 在生產過程中 PCB電路板s, 阻抗處理至關重要. The reasons are as follows:

1. The PCB circuit (bottom of the board) should consider plugging and installing electronic components. 封堵後, 應考慮電導率和訊號傳輸效能. 因此, 阻抗越低, 更好的, and the resistivity should be less than 1&mes;10 per square centimeter -6 or less.

2. The production PCB電路板工藝必須經過沉銅過程, electrolytic tin (or chemical plating, or thermal spray tin), 連接器焊接, 等., 這些連接中使用的資料必須確保底部的電阻率, 為了保證電路的整體阻抗較低，以滿足產品品質要求, 並能正常工作.

3. 鍍錫 PCB電路板s是整個電路板生產中最容易出現的問題, 這是影響阻抗的關鍵環節. The biggest defect of the electroless tin coating is easy discoloration (easy to be oxidized or deliquescent) and poor solderability, 這將導致電路板焊接困難, 高阻抗, 導電性差, 或董事會整體績效不穩定.

4. 中的導體中有各種訊號傳輸 電路板廠. 當需要新增其頻率以新增其傳輸速率時, 如果電路本身因蝕刻等因素而不同, 層壓板厚度, 導線寬度, 等., 阻抗值將改變., 使其訊號失真，電路板效能下降, 囙此，有必要將阻抗值控制在一定範圍內.

電子行業, 根據行業調查, the most fatal weakness of the electroless tin coating is its easy discoloration (easy to be oxidized or deliquescent), 釺焊效能差導致焊接困難, 和高阻抗導致導電性差或電路板整體效能不穩定., 容易形成長錫須，導致PCB電路短路，甚至燒毀或起火.

據報導，20世紀90年代初，昆明理工大學在國內首次開展了化學鍍錫的研究, followed by Guangzhou Tongqian Chemical (enterprise) in the late 1990s. 到現在為止, 業界已經認識到這兩個機构是最好的. 其中, 根據我們的連絡人篩選調查, 許多公司的實驗觀察和長期耐久性測試, 經證實，通前化工的錫層為低電阻率的純錫層, 導電性和釺焊質量可保證在較高水準. 難怪他們敢於向外界保證塗層可以保持顏色一年, 無起泡, 無剝落, 和永久性錫須，無任何密封和防變色保護.

後來, 整個社會生產產業發展到一定程度, 許多後來的參與者經常相互複製. 事實上, a considerable number of companies themselves did not have the R&D or initiative capabilities themselves. 因此, many products and their users’ electronic products (circuit boards) The bottom of the board or the overall electronic product) performance is poor, 而效能不佳的主要原因是阻抗問題, 因為在使用不合格的化學鍍錫工藝時, 它實際上是鍍錫在 PCB電路板 It is not really pure tin (or pure metal element), but tin compound (that is, 它根本不是金屬元素, 而是一種金屬化合物, 氧化物或鹵化物, or more directly a non-metal substance) or tin A mixture of compound and tin metal element, 但是用肉眼很難找到

因為 PCB電路板 is銅箔, 銅箔的焊點上有一層鍍錫層, and the electronic components are soldered on the tin-plated layer by solder paste (or solder wire). 事實上, 焊膏正在熔化. The state soldered between the electronic component and the tin plating layer is metal tin (that is, the metal element with good conductivity), 囙此，可以簡單地指出，電子元件通過鍍錫層連接到PCB底部的銅箔上, 所以鍍錫層的純度和阻抗是儀器的關鍵； 但在電子元件插入之前, 當我們直接使用儀器檢測阻抗時, 事實上, the two ends of the instrument probe (or called the test lead) first touch the copper foil on the bottom of the PCB板. The tin plating on the surface is then connected to the copper foil at the bottom of the 多層PCB板 傳達當前. 因此, 鍍錫是關鍵, 影響阻抗的鍵和影響整個PCB效能的鍵, 這也是容易被忽視的關鍵.

我們都知道, 除了簡單的金屬物質, its compounds are poor electrical conductors or even non-conductive (also, this is also the key to the distribution capacity or spreading capacity in the circuit), 囙此，在錫化合物或混合物的鍍錫中，存在這種准導電性而不是導電性, the existing resistivity or the resistivity after the electrolysis reaction due to future oxidation or damp and the corresponding impedance are quite high (enough to affect the level or signal transmission in the digital circuit) and The characteristic impedance is also not consistent. 囙此，它將影響電路板和整個機器的效能.

因此, 就當前的社會生產現象而言, 底部的塗層材料和效能 多層PCB 是影響整個系統特性阻抗的最重要和最直接的原因 多層PCB. 以及濕電解的可變性, 囙此，它的阻抗帶來的令人擔憂的影響變得更加不可見和多變. 其隱匿的主要原因有：一是, it cannot be seen by the naked eye (including its changes), 其次, 無法持續量測., 由於其隨時間和環境濕度的變化而變化, 它總是很容易被忽視.