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.

63
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 ...
25
votes
2answers
10k 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 ...
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 ...
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 ...
8
votes
5answers
10k 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
2answers
9k 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 ...
23
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 ...
37
votes
11answers
31k 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 ...
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 ...
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 ...
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 ...
8
votes
1answer
10k 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 ...
6
votes
2answers
1k 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 ...
29
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 ...
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 ...
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
3k 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?
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 ...
4
votes
1answer
545 views

Analog switch with a fixed state when not powered?

I am looking for a chip that could handle DPDT (or SPDT, or ultimately SPST) analog switch for audio routing (in the mOhm range resistance) and can guarantee one state when there is no power supply. ...
8
votes
1answer
501 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 ...
3
votes
3answers
1k views

DDR3 routing: swapping data wires

Is it possible to swap wires in data bus between CPU and DDR3 x16 memory for routing optimization? So, for data lines depends on the correct order? For example connect DQ0 on CPU to DQ1 on memory ...
11
votes
2answers
584 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 ...
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? ...
5
votes
1answer
680 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
1answer
396 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?
1
vote
1answer
363 views

Does a Ground plane in Eagle still need connections?

Before I added a ground plane my ratsnest was showing the needed GND connections which I still needed to make. I added a Ground plane and now they are automatically gone. Is this normal? I can ...
0
votes
1answer
939 views

LVDS: length matching within a pair and between pairs

I'm interested in the LVDS communication between a Zynq (Xilinx, xc7z020-1C) and a camera (ON semiconductor Python 1300 NOIP1SE1300A−QDI). I have read some articles about USB2.0 where the maximum ...