Questions tagged [trace]

Lanes of copper on a printed circuit board, for carrying current or signals between pads

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votes
2answers
974 views

What should be considered when sizing trace widths for digital logic signals?

For traces that carry a static DC current, it's pretty easy to calculate the minimum trace width based on the required ampacity of the trace. However, I'm not sure what should be considered when ...
6
votes
2answers
2k views

Power Plane and Decoupling Capacitors Routing

Forgive me for my simplicity. I'm just a hobbyist and not an engineer by trade. I am trying to make my first 4 layer PCB in Eagle and I have a question I cannot find the answer to regarding power ...
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3answers
409 views

11A trace width

Using this PCB Trace Width Calculator the external tace width for 11A (default settings) is suggested as 8.21mm. Is this acceptable? I was expecting something bigger, and just wanted to check that ...
2
votes
2answers
2k views

In Altium how do you increase the trace width from a Pour to GND Vias and Pads?

In my PCB layout I have a ground power connector and several pads where I would like thick traces to connect to the ground plane. When I use the polygon pour feature, it will connect these with 4 ...
7
votes
4answers
24k views

How to calculate parasitic capacitance in a trace?

I am given the equation for parasitic-capacitance as: \$ C = \dfrac{\epsilon_r \cdot \epsilon_0 \cdot L \cdot W }{ d }\$ I am also told my trace is to be 1000 micrometers long (1mm) and 45nm wide. ...
44
votes
4answers
59k views

How to make traces on an universal PCB?

I hope this question won't be closed as too subjective. I'd like to know best practice - how to make traces on universal PCB's with individual holes without traces (like the following image). My idea ...
1
vote
1answer
275 views

SDRAM on opposite side of board with respect to uC

Just a quick question. Is it advised against to place a high speed memory device on the opposite side of the PCB with respect to the microcontroller? And if it is ill advised, how is it possible to ...
4
votes
2answers
2k views

Why Altium routes trace to the side of the pad?

I am curious, are there any reasons why Altium tends to route a trace to the side of a pad, instead of the top? The top looks more logical, since it will not disturb other traces in a SOIC for example....
5
votes
1answer
923 views

Trace width to 0805 pad?

How worried should I be if I route wider than 10 mil trace to 0805 pad? Would 16, 20 or 24 mil trace cause soldering problems without making 10 mil neck?
5
votes
2answers
722 views

Satisfactory Margin for Traces from PCB Edge

I've had problems routing too close to the edge of a PCB before and was wondering if there's a suitable rule-of-thumb that I should use (maybe to put in a design rule in Altium somehow with my keepout)...
1
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2answers
1k views

How do you adjust the trace rotation on a Hameg HM 307?

I have a [rather old] Hameg HM 307 oscilloscope with the trace rotation slightly off. There is no trace rotation adjuster anywhere on the outside of the device. The user manual mentions that it is ...
3
votes
3answers
3k views

Repairing broken trace on commercial board

A friend has a USB flash drive on which the SMD USB connector broke off. When it broke, it pulled the pad traces off the board with the solder. We are trying to think of a way to reconnect the ...
4
votes
3answers
4k views

How to measure propagation velocity through a trace on a pcb?

With a pcb in hand, how to measure the propagation velocity of a path from point A to point B, with accuracy in the picoseconds range?
1
vote
1answer
305 views

Unoccupied SMD and TH pads and noise/interference/capacitance

Imagine a rather noise sensetive application, My question is if there are unoccopied pads for SMD and through-hole are existing on the board and somehow connected to other components through theire ...
2
votes
2answers
2k views

How to calculate typical signal trace clearance?

Knowing nothing more than most of the signal traces on a project are 7.5mil and it's a high end audio product, i.e. it's not a high frequency or any 'advanced' application, what would be a safe ...
2
votes
3answers
3k views

Eagle Schematic and Board layout design for simple opamp module questions

Hopefully I'm not doing anything illegal, I posted a very similar question a few days ago, but this one is different. Here is what I've been working on the past couple days, trying out different ...
16
votes
4answers
3k views

When laying out circuit board traces, what impedances do I need to consider?

I do low-speed circuit design for microcontrollers and such (usually at less than 20 MHz), and now I'm getting started on some more high-speed circuits. What I want to know is: What considerations ...
5
votes
2answers
1k views

LM13700 Question

I'm currently troubleshooting a state-variable filter I built. All of the filter types work, but the resonance pot has no effect. Tracing a sine signal through the feedback pathway, I found that it ...