45
votes
Accepted
Have I placed too much on this PCB layout?
I assume that you are using the autorouter because you think it will save your time. But I have some bad news: it is said that PCB layout is 80% component placement, 20% routing. You can't just slap ...
- 12.6k
25
votes
How do I separate ground planes on a PCB with two different voltages?
Simple answer is you don't split planes unless you know what you are doing and why you are doing it.
Separate the ground planes and route signals over the the gap in a split ground planes at your own ...
- 57k
24
votes
Accepted
What is an ideal layout for a normally-open solder jumper?
Take this layout:
|¯¯\ \¯¯|
|__/ /__|
Just make the arrows better than I did here :D
Slide with solder left to right to close, right to left to open. Reduce the ...
- 571
23
votes
Have I placed too much on this PCB layout?
Unlike what others have said, using the auto-router isn't the problem. They are right in that you can't just throw a whole design at the auto-router and expect it to solve everything for you. But, ...
- 314k
23
votes
Accepted
What breadboard simulation software is this?
It is most likely Fritzing.
It is an educational free software quite popular among newbies and teachers. It can draw wiring diagrams like the one you posted, or true schematics and even PCB layouts.
...
20
votes
Accepted
What is the purpose of copper planes in a switching power supply?
Lower track impedance
In a switching regulator, the track impedance matters a lot. Not only resistance, but also inductance, and both are reduced when using wider tracks (or planes).
Heatsinking
A ...
- 1,748
20
votes
Accepted
Mounting components on both sides of a PCB
First off, use a 4 layer board. Not only does it make layout easier but inner ground and power planes provides a barrier against front/back crosstalk. Also, 4 layer is not much more expensive than 2 ...
- 14.2k
20
votes
Have I placed too much on this PCB layout?
The auto-router isn't magic. And shouldn't be used to do full boards. You first need to route the important bits yourself. Like power, high speed and bypass caps. Then you can let the auto-route do ...
- 23.6k
18
votes
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Can you put a through-hole part behind an SMT part?
The hole for the connector would be near the center of the MCU package, away from the pins.
This is a very bad idea.
Usually the pins from through-hole parts stick through the board by at least a ...
- 133k
17
votes
Mounting components on both sides of a PCB
Adding to Dirk's Answer
Be aware, mounting on both sides of a board may not buy you as much real estate as you might be imagining.
When it comes to board density, your ability to route traces tends ...
- 46.9k
16
votes
Accepted
I painted myself in a corner. How to layout?
Your suggestions are spot on.
Solder your components first, but think about what you could use as a wire, e.g. a resistor can be used as a jumper. ICs are the main thing to put in first, as they are ...
- 7,969
16
votes
I painted myself in a corner. How to layout?
Even though you are using perf-board to build your projects, there is nothing stopping you from using schematic capture and PCB layout software to lay out the placement of your components.
Doing this ...
- 665
16
votes
Placing of capacitor close to IC power pin - logic
The black art of decoupling.
The reason you put decoupling capacitors close to the required IC is to supply current for the high frequency signals. This means you want to reduce the inductive loop ...
- 4,146
15
votes
Why MOSFET source is indicated with arrow ?
IC MOSFETs aren't the same as their discrete counterparts
You are correct in that laterally diffused four-terminal MOSFETs (such as those that make up CMOS ICs) are symmetric devices -- the substrate ...
- 9,008
15
votes
What is an ideal layout for a normally-open solder jumper?
The correct answer is probably: there exists no ideal layout.
Or at least none which the PCB CAD and/or manufacturer will approve. Usually the default clearance area around a pad/trace is too wide to ...
- 21.6k
14
votes
Accepted
Quad SPI PCB layout
For FR4, using effective epsilon of 3.25 we get the wavelength of a 80 MHz signal in the PCB at 80 by calculating
wavelength = (c/f) * (1/sqrt(epsilon)) = (300000000 m/s / 80000000 1/s) * (1/sqrt(3....
- 7,727
14
votes
Have I placed too much on this PCB layout?
You have made one of the biggest mistakes a newbie can make, and that is trust the autorouter to do your work for you. This is a huge misunderstanding among hobbyists, and that is that the autorouter ...
- 21.5k
14
votes
Accepted
Pie shaped stubs in RF supply PCB layout
These are called radial stub; if you have a pair of them, it's bowtie, or butterfly stubs.
They indeed (at least here, as far as I can tell) fulfill a impedance matching role: Think you want to ...
- 98.4k
13
votes
Kicad Ground Pads are not completey connected with Ground plane
No Thermal Relief - Do you really want to do that?
Thermal reliefs are enabled by default for a reason. Large copper planes act like an excellent heatsink for the circuit board. This is both a ...
- 7,267
12
votes
How should chips with pins on bottom be drawn?
A schematic is not meant to be a drawing of a circuit, and shouldn't be used that way. The "pins" in a schematic just show connections. Put them wherever they need to go to make the drawing ...
- 30.5k
12
votes
Accepted
KiCAD: Cannot see traces on a PCB side which has been filled with copper
Try pressing B. That will re-draw all fill zones on the board.
- 36.8k
11
votes
Why MOSFET source is indicated with arrow ?
The arrow doesn't indicate the direction of current flow, it indicates the PN junction between the body and the channel.
If you use the 4-terminal symbol, it is in fact often symmetric:
In IC ...
- 133k
11
votes
What is the purpose of copper planes in a switching power supply?
Heat and low impedance for the high current paths. Some of the land area on this board might be non-critical but when you have the empty board space it provides a little extra safety margin.
It is ...
- 3,731
11
votes
Have I placed too much on this PCB layout?
An economic perspective:
So, this is a hobby project.
In this case, consider the number of hours you will spend doing your layout versus the cost of a slightly larger board. Some manufacturers (like ...
- 80.3k
11
votes
Is it ever bad to run an IC VCC trace next to a ground plane with 1mm clearance?
In general, it's good to run Vcc as close as possible to the ground copper that will carry its return current. This reduces the size of the current return loop, which minimizes radiated emissions and ...
- 133k
11
votes
Design of 50 ohms RF trace for 2.4GHz...Double layer FR-4 PCB
Your calculations check out for the given values, but keep in mind that the dielectric constant of FR-4 is not tightly controlled, and may vary between 4.35 and 4.7 between manufacturers [1]. Since ...
- 138
11
votes
Accepted
How should chips with pins on bottom be drawn?
I'll start by answering your second question. Generally you should place pins in your schematic symbol so that it produces the neatest schematic possible. Usually this means power on the top, ground ...
- 21.5k
11
votes
Accepted
PCB Crystal Layout
Initial Design Review
The first thing I notice is your MCU ground is only connected to the main ground plane via a tiny thin trace that runs around the crystal:
This means all the current return ...
- 68.9k
11
votes
Accepted
How necessary are gate resistors for MOSFET gate driving?
The gate resistor does two things: it dampens the Colpitts or tuned-gate oscillator mode when a very low impedance is connected, and sets switching speed.
Oscillation mode, first:
simulate this ...
- 43.7k
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