Ground Plane

One of the junctions, which is between the ground plane and the metal particle is mechanically fixed, while another one which is between the particle and the STM tip is adjustable. 

Figure 3. SE two-junction system consisting of a scanning trm-neling microscope (STM) tip and a metallic nanoclusters as a central electrode on a ground plane.

Note that a typical circuit schematic makes no indication or mention of even the existence of this very useful and necessary ground plane. Further, very rarely do IC designers have a precise model of the PCB built into their magnificent simulators—which may explain how they manage to prove almost any hypothesis they may be favoring on a particular day ... 

Many vendors have come up with interdigited capacitors (or IDCs). These extra low ESL capacitors are based on the same principle with which I built my monolithic 5V/50A Flyback described in Chapter 5, titled Maximizing the Effectiveness of the Ground Plane. See Figure 4-17. As you can see, they must have been a pain to lay out inside the chip, but wait until you try to connect them on your PCB without defeating the very purpose they... 

Figure 5-5 How DC and AC Return Currents Flow in a Proper Ground Plane...

A thoughtless cut in the Ground Plane can divert the return current away from its preferred path (underlying the forward trace), thereby increasing the area of the enclosed high-frequency current loop and therefore also the inductance... 

Figure 5-7 How Cuts in the Ground Plane Can Reduce Its Effectiveness...

Finally, in Figure 5-7 we understand how a thoughtless cut in the ground plane (perhaps for routing between adjacent layers) can prevent the current from flowing in its desired path and effectively ruins its effectiveness. Further, we have also managed to create a slot... 

You have to follow the gray current loops that show how the Gate drive current flows. The lower Fet is in effect very close to the IC, because the ground plane cancels most of the... 

Note that if the upper Fet were a P-Fet, its driver s return current would usually flow through the ground, not the SW trace (there would be no bootstrap circuit present). So a P-Fet/N-Fet combination is actually more forgiving in terms of PCB layout (so long as we have a good ground plane ). 

Keeping the feedback trace short may not always be physically feasible. We should realize that keeping it short is certainly not of the highest priority. In fact, we can often deliberately make it long, just so that we can assuredly route it away from potential noise sources. We can also judiciously cut into the quiet ground plane to pass this particular trace through, so that it is, in effect, surrounded by a sea of tranquility. ... 

We should not think that heat is lost only from the copper side. The usual laminate (board material) used for SMT (surface mount technology) applications is epoxy-glass FR4, which is a fairly good conductor of heat. So some of the heat from the side on which the device is mounted does get across to the other side, where it contacts the air and helps reduce the thermal resistance. Therefore, just putting a copper plane on the other side also helps, but only by about 10 to 20%. Note that this opposite copper plane need not even be electrically the same point it could for example just be the usual ground plane. A much greater reduction of thermal resistance (by about 50 to 70%) can be produced if a cluster of small vias (thermal vias) are employed to conduct the heat from the component side to the opposite side of the PCB. 

Translating to the ground plane, since the pulse wavefront is perpendicular to the slant range direction, we get the range resolution on the ground to be... 

Dielectric constant is directly proportional to the capacitance of a material. Present computer operations are limited by the coupling capacitance between circuit paths and integrated circuits on multilayer boards since the computing speed between integrated circuits is reduced by this capacitance and the power required to operate is increased.11 If the dielectric constant is reduced a thinner dielectric provides equivalent capacitance, and the ground plane can be moved closer to the line, so that additional lines can be accommodated for the same cross-talk. Thus, the effect of a low dielectric constant will be to increase the speed ofthe signal and improve the density of the packaging, and this will result in improved system performance.2... 

Minimal (Sample on Ground Plane) Plasma Cleaning Plasma Anodization (Oxygen plasma) Plasma Etching Plasma Ashing (Oxygen plasma)... 

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