Mitigating Power Bus Noise with Embedded Capacitance in PCB Designs
نویسندگان
چکیده
This paper investigates the power bus noise and power bus impedance of printed circuit boards with four different kinds of embedded capacitance. These boards have power-ground plane pairs separated by a very thin layer of material with high dielectric permittivity. It is shown that embedded capacitance effectively reduces power bus noise over the entire frequency range evaluated (up to 5 GHz).
منابع مشابه
Importance and Limitations of Modeling Parasitic Capacitance between Package and PCB for Power Bus Noise and Radiation
Power and ground planes on multilayer PCBs can effectively radiate electromagnetic fields excited by the IC simultaneous switching noise. The high frequency electromagnetic radiation is often calculated from the electric field along the edge of the PCB, which can be estimated with a cavity model using magnetic walls. The excitation of the cavity modes is related to the via current passing throu...
متن کاملPrinted Circuit Board Power Bus Decoupling Using Embedded Capacitance
The purpose of decoupling capacitors on printed circuit boards is to meet the instantaneous current demands of high-speed active devices while minimizing power bus noise. Embedded capacitance is an alternative to discrete decoupling capacitors and is achieved by taking advantage of the natural capacitance between the power and ground planes. This paper investigates the electrical properties of ...
متن کاملQuantifying SMT Decoupling Capacitor Placement in DC Power-Bus Design for Multilayer PCBs
Noise on a dc power bus that results from device switching, as well as other potential mechanisms, is a primary source of many signal integrity (SI) and electromagnetic interference (EMI) problems. Surface mount technology (SMT) decoupling capacitors are commonly used to mitigate this power-bus noise. A critical design issue associated with this common practice in high-speed digital designs is ...
متن کاملThe Development of a Closed-Form Expression for the Input Impedance of Power-Return Plane Structures
In multilayer printed circuit boards, the noise on the power bus is influenced by the impedance between the power and ground planes. Power-bus noise estimates require an accurate estimate of the power-bus input impedance. This paper develops a closed-form estimate of the input impedance for circular power-return plane structures. When the structure is lossy (e.g., boards employing embedded capa...
متن کاملPower Bus Isolation Using Power Islands in Printed Circuit Boards
Power islands are often employed in printed circuit board (PCB) designs to alleviate the problem of power bus noise coupling between circuits. Good isolation can be obtained over a wide frequency band due to the large series impedance provided by the gap between the power islands. However, power bus resonances may degrade the isolation at high frequencies. The amount of isolation also depends o...
متن کامل