去耦电容
去耦电容是電路中裝設在元件的電源端的電容,此電容可以提供較穩定的電源,同時也可以降低元件耦合到電源端的噪聲(解耦),間接可以減少其他元件受此元件噪聲的影響。[1]
在共享导体的电路中,共享电源的时候,当一个器件需要对外提供输出的时候就会同时拉低该导体的电压,产生噪声耦合到共享的电路中。在有噪声的环境中,这些電磁波会在导体内感应出电压信号,影响回路中的元件。在数位电路中,器件容易在临界位置由于干扰而产生错误的信号,从而产生错误的动作。去耦电容可以減少以上情形的發生。
去耦电容一般都安置在元件附近的电源处,以減少布线阻抗對滤波效果的影響。去耦电容多使用陶瓷电容,其数值由电压信号最快上升和下降速度确定。
參考來源
- Don Lancaster, TTL Cookbook', Howard W. Sams, 1975, no ISBN, pp.23-24
外部連結
- ESR and Bypass Capacitor Self Resonant Behavior: How to Select Bypass Caps – article written by Douglas Brooks
- Decoupling – decoupling guide for various frequencies by Henry W. Ott
- Bypass Capacitors, an Interview With Todd Hubing – by Douglas Brooks, President, UltraCAD Design, Inc.
- Choosing and Using Bypass Capacitors – application note from Intersil
- Power Supply Noise Reduction – how to design effective supply bypassing and decoupling networks by Ken Kundert
- Circuit Board Decoupling Information – decoupling guidelines for various types of circuit boards
- Active Decoupling Capacitor – Circuit allowing reduce volume of high voltage electrolytic capacitors
- Minimizing Crosstalk in Wiring and Cabling – presentation by Richard J. Mohr at the IEEE Long Island EMC Section Meeting
- Basic Principles of Signal Integrity – Altera whitepaper
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