EEVblog #1085 - Bypass Capacitors Visualised!

What people said

Recommends DerStrom8 · 2016-12 · Electrical Engineering Stack Exchange · on “Routing and placement of decoupling capacitor when using power plane”

As others have mentioned it's important to place the decoupling capacitors as close to the IC pins as possible to minimize the trace inductance between the capacitor and the IC supply pins. Otherwise it defeats the purpose of the decoupling capacitor. Power pours are a great way to make connections and are perfectly acceptable in your case. It's important, however, that the supply voltage "hits" the capacitor first and THEN goes to the IC. In other words, you should not have the power plane connect directly to the IC supply pins using thermals. Instead, have it connect to the capacitor using thermals and then have a discrete trace connecting the capacitor to the pin. So instead of your first

Recommends Bimpelrekkie · 2018-05 · Electrical Engineering Stack Exchange · on “How to find coupling and decoupling capacitor values?”

My doubt is how do we choose those values exactly? We don't! No capacitor is ideal, there is always series resistance and inductance to be considered. To learn more watch this EEVBlog video by Dave Jones [LINK] . Note that bypass capacitor is just a different word for (supply) decoupling capacitor. More on the effect of different types of capacitors is demonstrated in this video [this video] . One of the conclusions you should draw after watching the videos linked above is that the choice of (bypass) capacitor depends a lot on the frequencies of the signals you want to decouple your supply for. In the case of (AC) coupling capacitors you want the most optimum capacitor for your signal frequencies

Recommends Jeroen3 · 2018-08 · Electrical Engineering Stack Exchange · on “Should I add bypass capacitor for every IC and Microcontroller?”

Theory of bypass capacitors is not as simple as *paralleled sums the capacitance*, see EEVblog #859 - Bypass Capacitor Tutorial [LINK] and EEVblog #1085 - Bypass Capacitors Visualised! [this video]

Recommends Pranit Pawar · 2019-06 · Electrical Engineering Stack Exchange · on “For decoupling an IC's power supply pins, is there any reason to use multiple capacitances when all the MLCCs have the same package size?”

Impedance of capacitor depends on the frequency of the signal passing through. Our job would have been easier had all signals been ideal. But they aren't! There are different frequency components in any signal. In order to selectively filter out the undesired signals, you need different frequency dependent impedances. Hence, different value capacitors! Check out this video by Dave Jones @EEVBlog [LINK] To get a visual feel of the concept watch this [this video]

Recommends DerStrom8 · 2020-04 · Electrical Engineering Stack Exchange · on “Does ground pour circumvent bypass capacitors?”

Please watch this video. It allows you to clearly visualize the effect of bypass capacitor placement, and the fact that whether current "hits" the capacitor first or last is entirely unimportant: [this video]

Recommends user1850479 · 2020-09 · Electrical Engineering Stack Exchange · on “Four Layer PCB Design”

I would like to jump to 4 layers pcbs, but everytime that I've looking in Google information, it's much complex than 2 layers. Impedance tracks, resistance of the tracks, decoupling capacitors for some impedance, EMIS, and the stack of course. I know this concepts separately, but when I'm designing I don't really know much more than the datasheet can tell me. I'm hesitant to answer this because I'm also inexperienced, but in my limited design experience 4 layer design is less complex than 2 layer because you have a dedicated ground and power plane. Conversely, when trying to make a 2 layer board work, you need to put a lot of care into minimizing the loop area of your power and ground traces

Cites Liquid Plasmas · 2019-11 · Electrical Engineering Stack Exchange · on “Massive pk-pk ripple on output using isolated DC-DC converter module”

It's been some time since I opened this question but I wanted to share the ultimate solution to help others new to diagnosing switching mode power supply characteristics (many of the comments helped but @VoltageSpike and @Elliot Alderson really set me on the right path). In the end this was mostly a matter of not understanding how to probe the transient voltages produced by an SMPS properly with an oscilloscope. After reviewing several different references: EEVBlog bypass capacitor overview: [this video] EEVBlog grounding strategies for single ended oscilloscope probes: [LINK] EEVBlog measuring power supply ripple and noise: [LINK] CUI's guide on measuring ripple and noise with single ended probe

Cites DerStrom8 · 2021-10 · Electrical Engineering Stack Exchange · on “PCB routing: isolate through-hole pins to force routing through decoupling capacitors?”

The truth of the matter is that it doesn't really matter if the current "hits" the capacitor before the pin of the IC or not. This has long been debated and recent studies have suggested that simply having the capacitor placed close to the IC is sufficient. Dave Jones of the EEVBlog did a video to help illustrate this, but he is most certainly not the only one. I believe Rick Hartley, one of the world's leading experts in high-speed board design, has also proven that it does not really matter the order in which the current "hits" the pins. In most cases, it is actually preferred to have the capacitor connected to the IC pin through a plane, as that is lower inductance than a discrete trace.

Cites ElectronicsStudent · 2023-03 · Electrical Engineering Stack Exchange · on “Power Supply and Routing Query”

Looks like a nice layout! I guess it will workjust fine in any hobby use case. If i wanted to "do it the perfect way", i would further improve it by: Decoupling each VCC pin with a dedicated 100n on the Top-Side with a similar placement - relative to the pin - as the C on pin 23. I would put a via between the IC pin and the Capacitor (Feel free to use larger pads/smaller drills for these vias to increase copper width around the drillhole, have an eye on production tolerances) connecting VCC to a different layer. EDIT : Decoupling capacitors mainly solve a single problem: Source impedance. Now, a common schematic consits of some application parts and a power supply. On a common board they are