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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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54 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 ...
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0answers
20 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 ...
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3answers
138 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?
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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 ...
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2answers
88 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 ...
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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 ...
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2answers
57 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 ...
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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 ...
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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 ...
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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 ...
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3answers
250 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 ...
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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 ...
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1answer
39 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 ...
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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 ...
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1answer
81 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?
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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 ...
2
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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 ...
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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 ...
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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 ...
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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?
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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 ...
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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 ...
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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 ...
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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 ...
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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. ...
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1answer
74 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 ...
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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 ...
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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 ...
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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 ...
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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, ...
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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 ...
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0answers
44 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 ...
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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 ...
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0answers
38 views

Relay Switching MCU Hanging/Reset

I am working on samD21 MCU to control the 16 relays. I am also using a circuit to detect the input AC switch status On/OFF (Connected serially to the relays). This is connected through optocoupler ...
0
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1answer
68 views

RS-232 to RS-485 transceiver

I'm new in communication protocols and ICs. I would like to know if it is possible to connect a RS-232 (TX, RX and GND) to a RS-485 (Vcc, A, B and GND). I only need a half-duplex communication. The ...
8
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4answers
1k views

Fiducial placement

I've read that fiducial should be placed on the corners of the PCB. And that no more 3 should be placed. Below are some questions I can't seem to find online. 1) Would it be a problem if there are ...
1
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1answer
45 views

pcb board to board connector dealing with ground current

Recently I am designing 2 separate pcb. one of them will be controller with low current signal paths and the other one will have mosfets to control high currents(about 10A). I am thinking of ...
7
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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....
4
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2answers
468 views

Does the distance between the signal lines (in terms of noise immunity) matter when wiring the board?

Studying the design of many boards, I noticed that the signal lines go very close to each other. A small distance between the tracks improves noise immunity or is it a matter of beauty and ...
2
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1answer
69 views

EAGLE - VIAS are smaller on the screen than in the actual gerber

Hi I have upgraded EAGLE to 9.5 and have one quite serious issue. The VIAS are displayed smaller than in the actual gerber file or manufacturing preview. Do you know the option which will force Eagle ...
25
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2answers
3k views

What's the meaning of Electrical Inches?

I was reading a PCB design notes and guidelines from Xilinx for their 7 series FPGAs and came across this sentence: The capacitors should be placed as close as possible to the FPGA. Any placement ...
1
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2answers
106 views

How can I layout these regulators to minimize board size and EMI?

I have three switching regulators. A 12V, 5V(green box), and 48V(purple box). The plan is to supply both regulators through -/+12vout pours. If I am trying to minimize board size while also ...
0
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0answers
23 views

Linking Attributes/Parameters in Altium Designer PCB

I have a test board with one unplated through hole pad and a string that needs to say the diameter of the hole in the top copper layer as shown: I would like to link the hole size and the value in ...
0
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0answers
9 views

Termination mode for CoolRunner CPLD (XC2C32A)

Fitting properties in Xilinx ISE offers some options for -unused and -terminate: ...
0
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1answer
33 views

Create open copper plane in EAGLE

I need to redesign an old PCB and for that I want to put down a open copper plane that won't get covered by solder mask. I tried it by creating a rectangle in the 'Pads'-Layer. The PCBs just arrived ...
1
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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 ...
0
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1answer
50 views

Do I need external pull up resistors for TX and RX lines in CP2102N?

I want to use it to program a microcontroller and this is the recommended set up from the data sheet. I was wonder If I need these resistors or not. I am not asking if STM32 chips require pull ups. ...
3
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3answers
116 views

PCB design for 50MHz

I'm designing a rather big PCB which will have 64 nokia 5110 LCDs arranged in an 8x8 matrix and will all be controlled by a single microcontroller. Each screen will have an 8-bit shift register as a ...
0
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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 ...
0
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1answer
54 views

Version control system for KiCAD which can deal with merge requests

When working on a project with a group of people it is often required to merge changes someone else has made into a master version of the project. However my EDA of chocie, KiCAD, does not seem to ...