Episode #125 of the Stack Overflow podcast is here. We talk Tilde Club and mechanical keyboards. Listen now

Questions tagged [routing]

Questions relating to the routing of printed circuit boards (PCBs) which involves the placement of tracks on the board. It may be performed manually however many PCB CAD programs provide an autorouter to assist in the process.

Filter by
Sorted by
Tagged with
66
votes
10answers
33k views

Why is there such a strong preference for 45 degree angles in PCB routing?

I've always wondered this: every single modern PCB is routed at 45 degree angle increments. Why does the industry prefer this so much? Doesn't any-angle routing offer more flexibility? One plausible ...
38
votes
11answers
32k views

Solid ground-plane vs Hatched ground-plane

So recently when i was routing a PCB , I came across the option to either fill/pour my ground plane with either solid or hatched copper. I've also noticed that the old arduino duemilanove also had a ...
31
votes
2answers
3k views

Ground ring — good or bad?

Here are two routings: Which is better? On one hand, the first is bad because ground ring is one-turn coil, hence induction current will be appear. On other hand, the second is bad because potential ...
30
votes
2answers
8k views

What is Manhattan routing?

In an answer by The Photon he mentions 'Manhattan routing' in regards to PCB design. I haven't found a lot of relevant information about this term on the internet; therefore the question: What is ...
29
votes
2answers
11k views

Purpose of “wave shaped” PCB traces

On some PCB designs, specific traces are routed in curious ways. This probably has to do with high frequency design considerations and general signal behavior that I am not familiar with. Let's take ...
27
votes
9answers
18k views

Do you layout in mil or mm?

I have been using 10 mil trace with 10 mil spacing. The PCB vendors quote that they like traces down to 7 mil. But then I ran across a PDF showing how to fan out a QFP to get all the signals ...
25
votes
6answers
31k views

Finding air wires in Eagle

I am almost done routing a board. However, is telling me that there is still one more wire. I have looked but I just can't seem to find it. Is there a to make Eagle tell me where it is?
24
votes
8answers
12k views

Advice on going from rat's nest to routed PCB

Can anyone offer any useful strategies on going from a rat's nest to a routed PCB? (I'm using Eagle and aiming to make single/double sided PCBs at home) Drawing the schematic is fine, but when it ...
16
votes
2answers
5k views

USB signal routing - Swap data lines using vias?

I'm making my second USB design, but the D+/D- pins on the MCU (atemga16u2) aren't in the right order for the micro B connector. What's the best practice for routing these to go the right way? My ...
15
votes
5answers
6k views

Anything bad to place a via on a pad?

Once I mistakenly placed a via on 0603 pad and didn't have any problem on soldering. I am routing another board now and I could save some space by placing some vias (0.3mm) on a 0603 pad. I wonder if ...
15
votes
2answers
1k views

Why would the VCC/GND pins of an ATtiny26 not be aligned?

In the following pinout diagram for an ATtiny26 microcontroller, a 20-pin IC: The VCC/AVCC and GND pins aren't aligned. Surely it would be easier for PCB design to connect these by going straight ...
14
votes
4answers
4k views

How can I improve this Ethernet differential pair?

This is my first 100 Mbit/s Ethernet project (I am doing it to learn more about differential signals). I did two things that I don't know if are good or bad in this particular case. One is to route ...
13
votes
1answer
4k views

GPS Design Review (RF Input)

I've designed a PCB in Eagle to host a GPS Receiver module and a GPS patch antenna. The RF input to the module is specified as a 50Ω unbalanced (coaxial) RF input. I used this calculator to calculate ...
11
votes
2answers
4k views

Acute angle routes in PCB

Following is from a PCB that I am presently working on. That particular path signals are of 100-400kHz signals. Is there any problem in having routes of this kind?
11
votes
2answers
598 views

Does pin order matter at all for this RAM?

I am trying to route a pic32 chip to a 128kB SRAM chip and having a bit of a hard time getting all 17 address lines and all 8 data lines connected. I am trying to tie the first 16 address pins to ...
10
votes
4answers
24k views

Changing all via and routing sizes at once (Altium Designer, PCB Design)

I have a completed PCB design drawn by Altium Designer. I want to increase via sizes. But there are too much of them, and changing all of them one by one will be a very long and bothersome work. Is ...
10
votes
2answers
4k views

Sharing an oscillator between two ICs

I have a microcontroller and an FPGA on the same board. If they're both going to run at the same clock speed, can I just use one oscillator to clock them both? There seems like there is something I ...
10
votes
3answers
5k views

How to join 3 traces is a PCB?

Usually I route my PCBs never making a 90º turn as best practices recommends, but sometimes there are points were 3 traces must intercept, if I always do 45º turns, in this intersection will be a 90º ...
10
votes
2answers
3k views

Is it normal to have a rats-nest of VCC/GND traces under an IC?

I'm attempting to route a simple board, the first I've done in 15 years since I routed a 12V linear power supply in the equivalent of mspaint. This board consists mainly of an LPC2387, which is an ...
9
votes
4answers
1k views

Can I put vias on routing I2C lines traces on FR4 PCB?

I am using a MSP430FR2633 micro controller and ADS122C04IPWR DAC over I2C at 100kHz. Can I route the I2C lines through vias in a 2 Layer PCB?
9
votes
4answers
3k views

Does there exist an IC that allows on-the-fly routing of signals?

Do there exist ICs with N input pins and N output pins which, either via EEPROM setting or via on-the-fly control by a microcontroller, allow one to route each of the N inputs to ANY of the N outputs? ...
9
votes
3answers
2k views

Why are ground pours isolated from each other on the top layer?

I am reading the application note from TI about the LM3409 evaluation board. In the board layout (Figure 3) the bottom layer is a single GND pour. But top layer has also some copper pours which end ...
9
votes
1answer
11k views

How to connect ground planes together

What is the best way to connect ground planes together ? I know that ground planes are connected together at multiple locations in order to keep a low impedance GND across the whole board and provide ...
9
votes
2answers
3k views

How can this layout be improved? (Gigabit Ethernet with discrete magnetics and POE)

Answer: No there is nothing majorly wrong with the layout, it turns out that the ethernet transformer was out of spec by 0.2dB on Insertion loss, when paired with the PHY IC we are using. Question ...
9
votes
1answer
545 views

Optimize signal return path with decoupling capacitors in a two layer board

I'm designing a pretty complex two layer board - I should really go for a 4 layer one, but that's not the point here. I'm done with component placing and routing and I'm doing the finishing touches ...
9
votes
1answer
762 views

Is my FPGA out of routing resources?

I have a Serial-ATA Controller design working on almost any kind of Xilinx 7-series devices, except for the Artix-7 device, which gives me headaches... The pure design (SATA 6.0Gb/s, 150 MHz design ...
8
votes
5answers
11k views

How can I make a decent ground plane in Eagle?

I've made a couple of simple PCBs as a hobbyist, and for the first time now I want to add a ground plane pour but I'm having some issues. As I have currently understood I need to: Create a polygon ...
8
votes
3answers
1k views

Via in between differential traces - how bad is it?

I'm working on a board that has some LVDS 2.5 signals. All the guides I've read about board layout say not to put vias in between the differential traces, eg this guide In a few cases it would be a ...
8
votes
2answers
10k views

Length Matching Differential Pairs

I am routing a PCB with an Ethernet connection and I am having a bit of trouble deciding on how best to route the TX and RX differential pairs. I have done the impedance calculations to figure out the ...
8
votes
1answer
3k views

My 12 MHz crystal does not oscillate

I am having trouble with a board I have had fabricated. The processor is an NXP LPC1788 Cortex-M3. I am using a 12 MHz external crystal to clock the processor as recommended in the datasheet. ...
8
votes
1answer
868 views

Routing Considerations for a Buck Converter

I am looking to build an adjustable output buck converter with the following requirements: Output 1.25-15V Input 20-24V Max current 5A (with limiting) Max output ripple 100mV (preferable but less ...
7
votes
2answers
11k views

Creating a high-current bus on a PCB

I'm planning a custom power-distribution / fuse-board for in-car application, but that requires carrying high currents (50A+ @12v*) on a PCB trace. Since I'd like to keep the board cost, and physical ...
7
votes
3answers
472 views

How to connect these pads

I have trouble connecting a THT HDMI Connector to a pcb: The HDMI Connector I'm talking about is this. The holes are too close to go in between them: (The blue line is 0.15mm thick) Is this usual (...
7
votes
5answers
1k views

In this schematic how are the caps such as C5, C6, and C9 connected? They are just going between my power source and ground?

I was told C6 is a bypass for the oscillator(X1). Now I have been building this circuit and I understand that in Eagle grounds are connected automatically and so are voltage sources without having to ...
7
votes
2answers
8k views

What is the best way to layout a PCB with crystal oscillators and MCU?

I have heard that the clock circuit is a noise source and that the clock circuit is also sensitive to noise. I believe that keeping the clock circuit close to the MCU and keeping other routes or ...
7
votes
2answers
273 views

USB-C Connector: How to route signals

I'm having trouble understanding how to route the signals out of the Molex 1054500101 Type-C USB connector - specifically the B1-B12 pins. The distance between row A and row B is only 0.5mm, too ...
7
votes
1answer
201 views

Best layer stack strategy for a 6 layer PCB with mostly SMD components

I am doing a design in a 6 layer PCB where both sides are populated. 95% of the components are SMD. The design is not "High Frequency" in terms of signal speeds....the fastest thing here is a MCU with ...
6
votes
1answer
416 views

What are the advantages and disadvantages of Manhattan-Style routing?

Manhattan-Style routing being the use of expressly east-west planes and north-south planes, using a via and changing planes when a signal changes direction. Comparing to freestyle routing, which lets ...
6
votes
1answer
205 views

Its ok use different layers for power?

For example in a double side board I'm using one layer as gnd and the other layer as power, and then I route the whole circuit inside the planes. Is that ok? Because I saw that usually both sides are ...
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 ...
6
votes
1answer
415 views

Things to be aware of when using voronoi shaped traces

I was thinking of giving voronoi shaped traces (e.g. http://publications.csail.mit.edu/abstracts/abstracts05/rus/rus.html for those who need an example, or just google image search it) a try. In ...
5
votes
2answers
1k views

Need recommendations on 4 layer board

I've looked around for the answer to this question, so I'll only ask the new questions. I am designing a PC board that has some need for circuits carrying 2 amps and some that are very low power ...
5
votes
3answers
8k views

'Unrouting' a ground plane on Eagle

I have been using Eagle for quite a while now but there is one thing that continues to bother me while I am using it. I have made the ground plane cover the shape of the board, however, when I am ...
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)...
5
votes
1answer
526 views

Electrolytics and PCB Routing

In researching whether or not it's common practice to run traces/place vias underneath electrolytic capacitors (specifically SMD electrolytics, didn't seem like it would be an issue to me), I came ...
5
votes
4answers
15k views

How to specify 100 ohm impedance on a pcb gerber

I've been using Altium for several years when I've needed to designed boards. However it's all been for simple analog designs and never anything too technical. I'm now trying to take a jump into a ...
5
votes
1answer
416 views

Acute angle on a pad or a via

It is better to avoid acute angle to join two routes (depending on current direction and waveform). I often see on board acute angle with a pad or a via. Is it bad? Should it be avoided as well?
5
votes
1answer
778 views

Does this PCIe routing look ok?

It is the first time for me to design a PCB with a PCIe bus. My first design failed, the bus is not working! Tom helped me in this question and instructed me how to correctly route a high speed bus - ...
5
votes
2answers
656 views

Routing USB, DVI and Ethernet signals on a large PCB vs using long cables

Properly routing USB, DVI and Ethernet signals over long distances (30 to 40 cm) on a PCB seems to be relatively challenging (skew, characteristic impedance, cross-talk, etc.). Yet using the standard ...
5
votes
2answers
6k views

Shortcut to change layer/add via whilst routing in Eagle

I am working on a board which requires a lot of vias and changes of layer whilst routing. I can change layer with the dropdown but that's going to take ages when I've got in excess of 64 vias to do. ...