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Questions tagged [pcb-design]

About designing the boards which carry the components of an electronic circuit. For questions about getting them built instead use PCB-fabrication. If your question is specific to a certain CAD tool, say which tool and version you are using.

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10
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3answers
262 views
+50

How to minimize impedance from capacitor to Gnd and Power planes

I'm trying to minimize the impedance from my capacitors to the Gnd and Power planes. 1. Via positioning I've learned from several sources that the best via positioning is close to each other. This ...
7
votes
3answers
228 views

Warming PCB in cold environment using SMD components only

I made a sensor board that needs to operate at about -55 degrees Celcius. Unfortunately, its key component often malfunctions when the circuit is cooled for days at the temperature and then powered up....
0
votes
2answers
55 views

How to connect a few shields correctly?

There are several shields on my PCB: shield on CAN-bus, on RS485, on Ethernet, on ENCODER motor signals. How do I correctly connect all these shields? If I use the star topology, which filters should ...
1
vote
0answers
21 views

TP4056 and ST32F103C8T6 shorting after few uses

Complete schematic: Top part: Lower part: This is the circuit schematic, top part is sensor, bluetooth, microcontroller, oled and pins related all working from 3.3v coming from regulation of a ...
1
vote
3answers
141 views

High Speed Signals PCB guidelines [on hold]

How quick does a signal have to be in order to be considered a high-speed signal? What are the limits and threshold where you can get away without special PCB layout?
6
votes
3answers
260 views

Which is the preferred approach to PCB layout for signal vs power traces in analog circuits, and things to consider?

I have had to layout 2 layer PCBs several times now for analog signals, and am just beginning to learn the process. I often face a similar question in one form or another with regard to laying out ...
3
votes
1answer
142 views

PCB Design Specification Document

My company has been designing PC boards since the early '80s. However, we haven't formalized our PCB Design procedures or preferences. Things like preferred PCB sizes, preferred location of mounting ...
0
votes
1answer
60 views

RC Filter Layout on PCB

Is there any difference in effectivity between the following two layout examples of an RC Filter? The first has the signal passing directly through the capacitor, while the second has the capacitor ...
1
vote
2answers
89 views

Why would this power mosfet be made in a surface mount package?

I’m looking at the CSD17303Q5 power mosfet which boasts a 100A max drain current. It confuses me why they have it in a VSON surface mount package because most pcbs would not be able to handle that ...
0
votes
1answer
88 views

Trying to get 2 Amps out of 3 Amp Regulator (MIC29302WU)

I am trying to get 5V,2A out of the MIC29302WU (TO-263 package) with an input voltage of 12V. The voltage drops to around 2.2V when trying to supply even 1.3A. Blowing canned air over the regulator ...
1
vote
1answer
63 views

Altium: Rectangular clearance around rectangular pads

I am designing a high voltage PCB so I have created clearance rules between nets equal to the pad spacing on the high voltage capacitors (4.5 mm). When I pour polygons, Altium appears to produce ...
0
votes
2answers
58 views

How to determine vias and through holes from 4-layer Gerber files

I'm trying to understand the difference between the vias and plated through-holes in these reference Gerber files. On layer 3, I don't understand why there are so many holes (vias)?. Why are some ...
0
votes
0answers
35 views

Antenova M20057 active antenna is not working

I have decided to use Antenova product which is M20057 (datasheet) as an active GPS antenna. I am using Quectel L96 GNSS module. There is an internal chip antenna on L96 module and I have tried the ...
0
votes
0answers
16 views

xpedition designer

I am here to clarify regarding on schematic creation using mentor xpedition designer,I finished my schematic drawing using xpedition dx designer so now i want to take my work another level(layout) for ...
1
vote
1answer
35 views

PcbNew invisible field still showing

I was editing a PCB and KiCAD crashed. When I restarted all fields that were previously invisible are now showing, even though their property is set to invisible. Is this a bug? Or an option I can ...
1
vote
0answers
38 views

Voltage spikes caused by stray wire

I recently had a PCB designed which has several analog, digital, and power elements. The board is powered by 24Vdc which is stepped down using an LDO to 3.3V and 5V. These voltages are used to power ...
0
votes
1answer
41 views

Altium: Vias not showing annular ring

I have vias connected to the polygon. In the old design (left pic) the vias have annular rings. But I modified few other things in the PCB. I removed unused vias in both new and old design. But now in ...
2
votes
3answers
571 views

How to calculate the size of ground plane we need to use in a PCB (printed circuit board) design [closed]

I searched about the ground plane and found out the ground plane is a good solution to reduce noise and get a seamless ground. How do I calculate the size of the ground plane for a PCB? When and ...
1
vote
2answers
61 views

PCB: ground plane thermals (in Eagle)

In a previous iteration of a PCB layout, I added a ground plane fill as recommended by many tutorials online (eg Sparkfun). By default Eagle creates thermals to ease soldering to the ground plane, but ...
1
vote
2answers
60 views

Temperature Sensor Selection for temp range of 160C to 240C with 1C Accuracy

I am attempting to select a temperature sensor for a controlled heating application. The sensor will need to be inserted into a chamber with a cartridge heater and steel ball bearings inside of some ...
1
vote
1answer
82 views

Can Vias be used on the board for branching tracks?

I need to split the RST line in two directions and also connect it to the opposite layer of the board. I did it like this: Is branching the RST line the right decision?
0
votes
1answer
244 views

Figuring out convenient footprint for given actual lead spacings

This a beginner question, but I couldn't find an answer in net. I want to place the following components call it from left to right Cap1, Cap2 and Res on a PCB: As you see above I also mentioned the ...
2
votes
1answer
40 views

Why do PCI Express riser/adapter cards have electrical components?

I'm looking to make a custom PCI Express right angle adapter because the ones on the market don't work with my space constraints. Now, because it's basically an extension cable, I'd imagine it should ...
0
votes
0answers
46 views

Create Nixie tube pin connector socket in eagle cad

I am unsure how to properly layout a socket for a nixie tube in eagle cad. I'm especially unsure how to match the exact dimensions and what tool in eagle to use to create a hole with copper on both ...
1
vote
1answer
150 views

Arduino PSU with battery backup (SLA) and mains/battery monitoring

Please could somebody review my following schematic, as it is my first attempt at a PSU circuit. The aim of this circuit is as follows: I am using a 15V (150W) PSU to power an Arduino, 2 separate 12V ...
0
votes
0answers
45 views

UART communication not working without injecting voltage in pin headers

I have a bluetooth module (rn4020) talking via UART to a stm32f103c8t6 MCU in a custom PCB, I also have an OLED screen and some pin headers for listening what either module receives (as seen in the ...
8
votes
3answers
3k views

Why are DIY PCB components placed at right angles?

I'm learning PCB CAD. I want to know why components seem to be placed at right angles and orthogonal to the PCB (assuming that it's rectangular). Since the traces are secondary to the placement of ...
0
votes
1answer
57 views

Oscillator connection

I have two questions here for how to connect the oscillator to a microcontroller (SPC584b): How can I determine the values of the capacitors? What is the need of SB2 & SB3?
0
votes
4answers
150 views

Designing a PCB with variable-sized component alternatives

I'd like to get a little PCB manufactured with a basic circuit that I can populate with components of various sizes. E.g. have a place where any of a range of possible capacitor sizes could go. So I ...
3
votes
2answers
215 views

Why are project files in Altium modified every time they are opened? Is there a way to prevent this?

I use Altium Designer 18. When I open a project file (.PrjPCB), the asterisk ("*") appears next to the project name indicating that the project has been modified, but I haven't actually made any ...
0
votes
1answer
98 views

Connection of LAN8742A nRST pin causes failure when ESD strike

My circuit uses LAN8742A ethernet phy. The system has a metal case and gets 220V AC to power supply board. After converting 5V DC it goes to my board that has Ethernet and mcu. I screwed case and ...
0
votes
0answers
33 views

Controlling a series of LEDs ( AC->DC via bridge rectifier)

I'm working on a PCB (Christmas Present) to take in A/C to a string of LEDs and control them (with transistors? and a microcontroller). This is a bit out of my league, but it is making me learn ...
0
votes
1answer
61 views

Designing PCB with AC Live and Neutral on two layers

I'm designing a smart socket that will route 240V AC Live and Neutral to a voltage regulator and also to a relay that will control the current flow. Due to the limited space, it will be easier to ...
6
votes
1answer
5k views

Analog & Power Ground Planes Doubts

Working on a new board, I have to face some requirements to ensure the performance of the whole system once is manufactured. PCB is a 4-layer one, and it has both analog and digital components. But ...
0
votes
0answers
33 views

Making a more efficient replacement for my diode

I am making a boost converter using the LM3481 IC (although it might be considered a sepic topology as well). Typically in a boost topology, you put a diode before the output capacitors so they don't ...
2
votes
3answers
5k views

Change Default Altium Footprint Part Designator Top Overlay Text Size

I got an Altium question. I'm trying to speed up my Altium workflow. Everytime I Design > Update Schematics, when I import all the footprints into the .PcbDoc the part designator overlay text is ...
9
votes
3answers
1k views

Traces in connector's solder keep out area

I'm designing with a Molex 87438-0443 connector whose PCB footprint includes a 'solder keep out area' between each pair of copper pads for each connector lead. It appears that the manufacturer wanted ...
0
votes
2answers
39 views

Plane Splitting - Single winding AC to dual rail on the same board as preamps

So I have asked a similar question and was wondering if I could trouble you guys for a little more advice. I believe I have taken all of the advice from before into account. Ill get right into it. ...
0
votes
1answer
75 views

PCB Pads vs Components Footprints in PCB design

I want to understand the process of PCB design using a software like Altium. I have come across two approaches as follows: Approach 1: While making the component parts library we make the footprints ...
10
votes
5answers
7k views

Why do some PCBs have the courtyard in the silkscreen layer?

I've seen quite a lot of PCBs which have the passive components outlined all the way in their silkscreen. Something like this: Here there is an outline around each passive which goes (almost) all ...
-2
votes
2answers
962 views

What are good alternatives to the dw01a used with TP4056?

Currently I have a 18650 battery charge and discharge circuit in my Board design as a "Emergency fall-over power. And I have some problems with it. First problem I see is that while the battery is ...
0
votes
0answers
59 views

Ground Planes, 0v or GND?

I have a board that has a dual voltage isolated DC-DC converter on it. The converter takes 0 an 5v in and gives -5,0,5 v out. The 0v of the input is actual ground. Most of the PCB uses the isolated ...
0
votes
0answers
31 views

Is it ok to put GND and VDD pours below IC (AS7265x)

I am designing a PCB to use with the AS7265x sensors. The datasheet states, on page 51: In order to prevent interference, avoid trace routing feedthroughs with exposure directly under the AS7265x ...
0
votes
1answer
29 views

Altium Designer multi sheet design quad op amp

I have to design an multi channel sampling device: there is an input stage with some filters, then digitization of them and some supplementary circuit. To create a filter, I want to use quad op amp, ...
2
votes
1answer
181 views

Proper way to route high-voltage tracks near THT components

I think this is not a duplicate of this question. My design has the following constraints: type and position of connectors pinout assignments 260 VDC / 2A for high-voltage tracks 12V / 200 mA for low-...
2
votes
2answers
143 views

Timing a circuit's 'on-cycle' after a push button switch is pressed

First off, thank you for reading all of this - you are the part of the internet that gives me hope for mankind. I’m looking for a circuit that I would think is relatively straightforward, but has a ...
21
votes
3answers
25k views

Mounting hole on a PCB

Here is a picture of 3 mounting holes on three different PCBs. The red one is what I prepared on Eagle CAD and used "hole" button on the left side menu , something like this: Do I need to use "...
0
votes
0answers
24 views

Parasitic Inductance - DPT circuit

I have a question about parasitic inductances. Let's take the figure below as an example, a DPT circuit is shown here. I have added an inductor (parasitic loop inductance). I would like to have a ...
0
votes
1answer
169 views

Help with reverse engineering a small PCB

I need to reverse engineer this small board (7.5 x 28 mm) which serves an inductive proximity sensor. I suspect some of the components are dated/obsolete but the board works well. Ideally I would end ...
0
votes
0answers
46 views

Altium net has only one pin in hierarchical design despite port connection

I am working on a multi channel hierarchical design in Altium 19 and getting an error 'net has only one pin' for all signals contained in buses routed between two sheets. Below is my top level ...