# Questions tagged [trace]

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

168 questions
Filter by
Sorted by
Tagged with
1k views

### Altium high current trace

I'm designing a PCB in Altium and I need to trace tracks that can support 20A. I used a PCB Track Width Calculator and I need a width of 10mm for my tracks. The problem is, how do you link the pads of ...
434 views

### Differential impedance calculation: reference plane doubt

I'm calculating the width and spacing for my differential signals to meet impedance requirements. I have downloaded Saturn Impedance Calculator for making calculations. My pcb stackup has embedded ...
2k views

### Does the impedance of a PCB track matter if the length of the track is far smaller than the wavelength of the signal?

I have a PCB with tracks of no controlled impedance. The longest track is shorter than 1/5000 of a wavelength. Does the impedance of the track even matter? If not, then at what length would I need ...
2k views

### Understanding USB Differential and Single Ended Impedance Requirements

The USB IF spec mentions the following for USB 3.0: This has me scratching my head. In my experience, $Z_{diff} < 2 Z_0$ -- typically around 1.6-1.8. So how is it possible to meet both the ...
368 views

### Can a PCB trace support peak currents?

I was wondering if a PCB trace can support peak currents, larger than the nominal current. E.g., using a PCB trace width calculator, a 7mm trace supports 8A, but can it support larger peak currents? ...
148 views

### Question about trace current capacity

I've been checking some online calculator (this one and this one) to determine the width of a PCB trace for a given current capacity, but I not sure if the value specified for current refers to direct ...
11k views

### How far can mains voltage arc in air?

I wondered this while soldering a mains voltage circuit board and was surprised by how close together the traces were. It has obvious implications in design of electrical plugs, and the proximity of ...
133 views

### Characteristic impedance of RF PCB when narrowing the trace width to fit pad

I am working on a PCB design that should be matched at a characteristic impedance of 50 Ohms. The circuit down converts a 2.4 GHz signal to a signal in the 2 Mhz- 100 Mhz range using a VCO and a mixer....
88 views

### Trace was cut during a modification of synthesizer, how to repair [closed]

I received a Roland TB303 synth that has issues. When I opened it to see what the issue was, to my horror I found that a prior owner had seemingly cut a trace intentionally. How are these fixed? Is ...
4k views

### Breakaway PCB Design

I am aiming for a breakaway PCB design for a small series where an unneeded compartment can be broken off. (See Image below) I saw this for example on the STM32 Nucleo boards, where it is used to ...
1k views

### Trace width & vias for PCB carrying 15vdc/1a

I am designing a PCB which includes a 3.3v circuit w/ a microcontroller than controls (via a relay) a higher voltage (max 15vdc, 1a) circuit. Is it OK to run that amount of current and amps on PCB ...
351 views

### PCB trace and antenna matching

I'm designing a pcb with a Sub-1GHz chip and I'd like to add a chip antenna on my design. I choosed one of the johanson technology products, especially this one https://www.johansontechnology.com/...
2k views

### Ethernet Trace Layout with PoE & Integrated Magnetics

I'm a hobbiest & I've put together a simple PoE board using a LinkIt Smart Duo, the AG9050-2BR and a Bel Fuse 0813-1X1T-57-F. The power circuit works but the Ethernet signal wont work. The ...
353 views

### Can a dental X-Ray machine be used to look at PCB

I have an old castaway PCB board that was being thrown out, but I am having a hard time figuring out where all the traces go. Could a dental x-ray device be used to scan it (thus making it easier to ...
532 views

### Long lines: whether or not to treat PCB traces as RF lines

My setup: 53 x 28 mm PCB, uC will run somewhere between 1 MHz and 8MHz. Dual layer PCB design. From the info I gathered on this site it seems there are two aspects to consider in deciding how to ...
389 views

### Minimize crosstalk using shield/guard trace with capacitor ground

I'm designing a PCB using this component http://www.ti.com/lit/ds/symlink/afe4403.pdf And from the datasheet page 90 layout guidelines I found point(2) which says If the INP, INN lines are required ...
70 views

### Will my square pad short if the pour isolation is too small?

How do I get the pour to isolate the pad and not the drill here? I'm assuming the square pad goes all the way through and will short my second layer (in teal). Am I correct? update: Confirmed! I put ...
419 views

### Why break a PCB trace plane into multiple parallel traces?

I have a vehicle battery maintainer (20A) that was overloaded and stopped working. On inspection I found a group of traces blown, however all the traces are connected at both ends. It looks like a ...
1k views

### Can a ground plane be used as a current return path? (DC only, no signals, no AC)

I'm creating an adapter which hosts two connector types and simply routes two connections from one connector into the other. Only two traces/connections are used; Vcc (about 6v) and GND Operating ...
603 views

### Is it necessary to have a 50 Ω impedance track after the matching circuit and the antenna for a space constrained RF mcu(MKW21Z) design?

I have followed quite a few RF MCU based designs from Texas Instruments like CC3200, CC2650 etc and in all of them I did not have to worry about the trace impedance between the MCU pins and the ...
410 views

### How is a trace formed?

I know it's the conductive connection between different points on a circuit board, but what is its form, how is it made? My confusion stems partly from this image of a PCB cross-section, which I ...
492 views

### Seemingly excess trace length reason [duplicate]

I was looking at the traces of a computer's mother board and noticed that some traces appear excessively long and zig-zaggy(Really couldn't think of a better term). I am wondering why the designer ...
66 views

### How to decide earth trace width in protection circuit?

I am using the earth trace for protection circuit in telecom system. The protection circuit includes MOV, sidactor & fuse. So please suggest How to calculate the Earth trace width.
41 views

### How do I register polygons as traces in Altium?

I've used the Place>Soild Region command to create polygon traces for my board. However when I highlight the traces by hovering over and pressing shift. The Net is connected but the highlight does not ...
170 views

New to Altium here, so my apologies in advances if some of my terms are off. Anyways, I'm looking for a setting that enables traces to be highlighted when clicking on a pad or via. This is the ...
316 views

### If I have an obtuse trace, will the complementary acute angle cause issues?

I was wondering if the complement of an obtuse trace would cause issues when routing, would it be better to have a 90 degree trace or one that comes in like this? or 90 degrees EDIT: Added a third ...
36 views

### How to display unroutable tracks early in eagle autorouting process

I felt like I spent a week trying to route the same circuit. I then look in the manual for hints, and it talks about how the status of the autorouter includes the number of tracks that it believes are ...
224 views

### Center trace between two pads

Is there a way in eagle to center a trace between two pads? and by center, I mean directly center it with even spacing on both sides of it. I'm asking because its easier to solder pads that aren't ...
3k views

I find a lot of online tools to calculate the capacitance between two traces (or a trace and a plane) on opposite pcb layers. One such tool can be found here: http://chemandy.com/calculators/...
609 views

### Thermal relief for thick PCB traces

A PCB trace that carries considerable current (~5 Amps) needs to be wide, on the order of 4mm. I am concerned that this wide and thick (70mil) trace may cause problems during hand soldering, but can ...
2k views

### Solder bridge in schematics and 0 resistors

I came across solder bridge in the schematics for STM32F4 Disocvery board and I don't think I fully understand the design here. For example in schematics they have a lot of solder bridge symbols like ...
374 views

### Why does the IPC standard allow for smaller clearance on inner layers than external layers?

Why does the IPC standard allow for smaller clearance on inner layers than external layers? In this thread it is alleged that external layers are susceptible contamination. That makes sense with home-...
1k views

### How does trace/via clearance affect parasitic inductance if they go to the same net

After reading [Mike DeSimone]'s response regarding good decoupling and bypassing practices I kept wondering about distance between wires (wire = trace or net) . [Mike DeSimone] comments that wires ...
175 views

### Best approach/practice to design PCB which can handle 50-80A current?

I'm designing a PCB which needs to handle high currents across various fuses, relays and connectors. The current ratings would be 8A, 20A, 50A, 80A. So I would like to know which is best approach to ...
1k views

### PCB trace capacitance

I am designing a capacitive touch keypad using cypress MBR series. The design guide has an excel spreadsheet to help with max trace length and button dia requirements. The idea is to keep the button + ...
7k views

### Design rf trace antenna 433MHz + 315MHz on pcb

I'm a hobbyist and I'm designing a PCB in Eagle that include micro controller and RF receiver and transmitter, 2 modules of 433mhz and 2 of 315mhz, I have a defined place on the PCB of 10x50 mm for ...
1k views

### How to choose trace width for very high current PCB?

I am currently designing a PCB layout for my team's high current, high voltage project and am having trouble with choosing my trace width. The circuit is composed of 12 inductors placed in series ...
383 views

### How to find current limit or resistance of current path that is a polygon in PCB?

I'm trying to understand what is the relevant path of current when I use polygons for PCB design. Edit: I'm particularly interested in the current limit in that path without destroying it. Please ...
3k views

### PCB trace clearance in 220V circuit

This is a pcb layout where I am converting 220V rms to a DC voltage (for microcontroller). The pcb has severe size constraints. This is one design I could come up with: Circuit explanation: Consider ...
145 views

### How large should PCB traces be to control a solenoid?

I'm working on an electronics project that'll regulate and offboard solenoid. The leads controlling the solenoid will need to sustain fairly high levels of current. This is the solenoid I'm working ...
549 views

### Negative consequences use epoxy glue to fix lifted SMD trace/pad

What are some unforeseen side effects using glue to fix SMD pads and traces that have been lifted off from the PCB board. It was for 0406 caps, the cap is soldered on the pad but both pads are lifted ...
3k views

### Altium 15 - Cannot see traces in 3D view

I am new to PCB designing and I've finished creating the my first prototype board. I want to send it to get printed but I'm worried that I haven't done my traces correctly because they do not show up ...
780 views

### Plane Resistance with Vias

I have a long and wide power trace (0.3" x 3") that is duplicated on several layers of a PCB. For some thermal purposes, there are many thermal vias punched into the trace (See Figure below). I ...
369 views

### Parallel bus trace width and spacing

I have been working on designing a PCB for a Z80 computer that I plan to sell a few times for interested people. The Z80 will work at a maximum of 8 MHz and has parallel lines going to a system ...
2k views

### Does my PCB Require 50 Ohm Impedance trace even if i am using external antenna?

I am using the Quectel M95 GPRS Modem in my PCB, and the hardware reference guide says "The Pin 39 is the RF antenna pad. The RF interface has an impedance of 50Ω. " I am using a u.efl connector and ...
2k views

### Extra spacing between some traces and the ground plane

I have seen several designs where there is extra spacing between some traces and the ground plane. For example, see the traces between the points A and B or C and D in the following picture (this is a ...
3k views

### How to route a trace on PCB with 50 Ohm impedance?

I used some online calculator to calculate parameters of trace so it has 50 Ohm impedance. I use FR-4, so H=1.5mm, T=0.035mm and Er = 4.5. 2-side PCB, one side with signals, the other with GND. I set ...
255 views

### Crystal grounds and minimal trace distance to leads

Some questions have already been asked about crystals but there's a few competing designs and I have a few "obsessive" type questions on layout. Here's a almost completed layout with a PIC16F ...