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Questions tagged [trace]

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

-1
votes
1answer
41 views

I2C PCB Troubleshooting / Trace Design Flaw

I have a board with an Atmel SAM D21E microcontroller that I need to connect 4 I2C devices (with conflicting addresses) to. It only has one I2C channel, however, so I am using a TCA9548A Multiplexer ...
0
votes
2answers
170 views

Why sometimes some PCB designer add extra traces to connect two pin to each other?

I've checked a PCB board which has designed by very famous company and I saw something weird.They connected two pin to each other 2 times and from the top and the bottom of the board I am going to ...
0
votes
0answers
26 views

Repairing damaged battery pad

Trying to fix up this PCB -- One of the batteries leaked and corroded a hole in one of the battery pads. I tried to fix it a while ago with some electrical paint, but it did nothing. I remember ...
2
votes
2answers
69 views

Replacing burnt traces

I have a tiny PCB that I've been working on and off of for a while now. I received it with leaking batteries, and it had corroded some of the traces off the board. Most recently, I tried redrawing the ...
5
votes
1answer
134 views

Routing large RF trace to small SMD pad

I am designing an RF board in Altium where due to the dielectric selected and its thickness, the trace width for a 50 ohm characteristic impedance is thicker than some of the SMD component pads. What ...
2
votes
2answers
120 views

Routing thick high current traces to small SMD pads?

What is the best practice for routing high current traces through the pads of small 0603 components? I have a wide high current trace which that passes through a 0603 decoupling capacitor. Initially ...
0
votes
0answers
49 views

wiring for an APC transformer

I have a transformer that was salvaged from an APC battery backup. I googled all the numbers, I found only one that was similar, but not enough. From what I understand, the middle wire is typically ...
1
vote
3answers
162 views

Minimum PCB Trace width with SMD components and Autorouter problem

I would like to receive some suggestions from you about the trace width for my PCB. I'm using some SMD components (ATmega328p TQFP32 and FT232), the main power is 5VDC at maximum 2A. I use also a ESP ...
0
votes
0answers
24 views

Analogue Video Trace Matching

I'm working on an analogue audio, video and sync board for my Dreamcast. Something I've been wondering about is the tolerance for analogue video, specifically RGB, in regards to the delta for trace ...
2
votes
3answers
106 views

How to fix incorrect routing to SMD transistor terminals

I've got a doozy of a situation: On this circuit I had made, I routed an IRL530N D2Pak transistor with Source and Gate switched....the large heat pad should be the gate input, but instead I routed it ...
0
votes
0answers
36 views

Antenna trace 135 degree bending

I designing PCB for SIM7600CE with space constraint.Here, I placing filter matching and the antenna section through 135 degree angle traces (GREEN MARKING).Is it Okay?Can I have any PCB guidelines? ...
25
votes
6answers
4k views

Is it OK to route a trace through a pad?

Will I have any trouble routing the traces in this way? (VCC and GND) Is it OK considering that the entire circuit current is under 50mA?
1
vote
1answer
69 views

DDR Trace Length Inside Package from Simulation Model

The DDR4 in question is a Micron MT40A512M16JY. From the vendor site, you can get the datasheets, specs, sim models. I assume from the sim models you should be able to see the trace length of each ...
1
vote
1answer
72 views

DDR3 trace length: need a confirmation

I am reading JEDEC DDR3 specification, and so many other documents on DDR3 guidelines. Before I move to pcb prototyping, I just need a confirmation. I connected all my lines, respected the grouping, ...
1
vote
0answers
35 views

Slewed fpga drive rise time on pcb to enet phy

What can cause rise times to be slewed from an fpga to an enet Phy? Can it be trace capacitance? This is a high density 14 layer board . Traces route from fpga to ribbon connector, along a short ...
0
votes
0answers
37 views

Faster 8051 not taking the slower 8051 pin status correctly

I'm trying to do a rather simple data transaction between two 8051 microcontrollers using a variant of the SPI protocol. The large one is a slave and the small one is a master. The documentation for ...
0
votes
1answer
28 views

Antenna CPW internal layer

I see on the internet showing CPW( coplanar waveguide) always placed on TOP layer with ground underneath. This is what I usually do. Is it possible to place a CPW in an internal layer? if so what ...
1
vote
0answers
84 views

How far away can DDR3 memory be placed from the SoC?

I thought of an idea where i have a pcb with a soc on it, and a seperate one with the DDR3 memory that can snap into each other. This way i can replace or debug specefic parts of the system and have e....
2
votes
1answer
46 views

How to set the width of all the traces together to the desired value before using autoroute option in Autodesk Eagle?

How to set the width of all the traces together to the desired value before using autoroute option in Autodesk Eagle? every time I use autoroute, the trace width is by default set to 0.0154mm. I have ...
0
votes
1answer
330 views

Is there available differential impedance calculation for this stripline configuration?

I am trying to calculate the differential impedance of a differential pair in a 4-layer PCB as follows: Layer: Low speed signal Layer: Power plane Layer: Differential pair Layer: Ground plane I am ...
0
votes
0answers
63 views

Oscilloscope Trace Appear Delayed

I saw a thing on my GDS-1052-U oscilloscope: if I set the time base to 25mS/div there appear a delay of the signal on the screen. So, when I rotate the knob for the time base to 25mS/div, there is a ...
3
votes
1answer
198 views

How can I account for package trace length in KiCAD?

The documentation I got for the MCU provides "package trace length" (in micrometers) as well as "package trace delay" (in picoseconds). For example like this - 6535.15 um package trace length for M_DQ[...
8
votes
2answers
1k views

thickest pcb track before hitting ridiculousness in digital circuits

Ok, you can call me ridiculous. But, When I make PCB's, I learned myself to get into a habit into making thick PCB traces for every wire including those that others would use maybe a 5 - 8mil width. ...
0
votes
3answers
226 views

Is it okay to use wider trace than actually required while designing a PCB?

I used eagle to recently, design a board with all trace widths 30 mills except a few as 20 mills. I actually didn't require traces this wide and 15 mills would probably have been enough. Does this ...
3
votes
4answers
483 views

Is it bad to run traces directly over each other on separate layers?

A bit new to PCB design, I have to run two traces between two pins, and the best way I can think of is to have one trace go to the bottom layer through a via and then run directly under the top layer ...
1
vote
1answer
112 views

Traces across transmission line

I am designing a PCB which has a chip antenna with a coplanar wave guide. Having a 4-layer PCB (stackup layer: rf signal, GND, POWER, signal) can I run traces across the antenna transmission line on ...
0
votes
0answers
413 views

PCB trace width / via size calculator for intermittent signals

Somewhat a duplicate of Can a PCB trace support peak currents? Are there rules of thumb for a PCB designer to compensate the output of via / trace width calculators to account for cases where the ...
1
vote
2answers
40 views

While performing the controlled impedance routing what about the current flowing through it?

While calculating the conductor impedance the parameters that we consider are the conductor width, conductor thickness, frequency & substrate parameters. For achieving the particular impedance ...
0
votes
0answers
50 views

Query relate to rf impedance matching

I am into RF design and I have some queries related to impedance matching and trace. We had an RF module and the module was connected to an antenna through a single trace with no LC components in ...
1
vote
2answers
872 views

Is there an ideal PCB trace width for data lines?

For a 1oz FR-4 PCB, is there an ideal PCB trace width for data lines? For power supplies, I realize wider is usually better, and power planes are preferred. But what about data lines? Is narrower ...
3
votes
3answers
905 views

50 Ohm Single Ended Signal Impedances on PCBs

I have a basic understanding of transmission line theory and how 50ohm traces are designed on a PCB. I was wondering what the origin of this 50ohm impedance is. Are single ended digital signals on ICs ...
1
vote
2answers
119 views

BGA break out and impedance control

I'm connecting two BGAs (0.8mm pitch) which are DDR3 signals. Vendor recommends 40 and 80 ohm for SE and diff traces. My PCB manufacturer suggests the following specifications for the diff traces: <...
2
votes
0answers
187 views

PCB trace caps (a.k.a. finger / interdigital caps) formula

I am trying to calculate a two-fingered, both on the same layer, capacitor. I have run into a few papers on it but they are taking a ground plane on the other side of the PCB into consideration and ...
0
votes
0answers
185 views

PCB trace is 50 ohms, for reflection can we detect the discontinuity point?

all, I've searched some information but still have questions. If it is all impedance control from the whole trace (driver -- PCB trace - device input), does this mean no any reflection in the real ...
1
vote
2answers
3k views

Why is length matching important for high-speed signals?

Broadly speaking, I understand that PCB trace length matching is important from signal timing and signal integrity point of view, but I want to know some more specifics about these two parameters and ...
0
votes
1answer
63 views

IC Pins with adjacent same net need to be made as common shape?

Attached is the layout I am working on. Please see the yellow circled area. It is a common net. I have kept it as separate trace in the layout for each pin. Is there any advantage by providing shape ...
1
vote
1answer
182 views

10BASE-T Layout Guidelines

How critical are parameters like trace length matching, differential impedance, vias, etc. when designing a 10BASE-T only application? I know that due to the reduced frequency, there is a larger ...
2
votes
3answers
705 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 ...
1
vote
2answers
279 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 ...
8
votes
4answers
1k 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 ...
1
vote
1answer
954 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 ...
0
votes
2answers
254 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? ...
0
votes
1answer
101 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 ...
6
votes
3answers
6k 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 ...
1
vote
1answer
93 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....
-2
votes
2answers
81 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 ...
0
votes
2answers
696 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 ...
0
votes
0answers
275 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/...
3
votes
2answers
1k 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 ...
0
votes
0answers
227 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 ...