About designing the boards which carry the components of an electronic circuit. For questions about getting them built instead use pcb-fabrication. If your question is specific to a certain CAD tool, say which tool and version you are using.
4
votes
1answer
669 views
How critical is the layout of USB data lines / how does my layout look?
I'm laying out the USB data lines on my board at the moment, and I'm just trying to get an idea of how well off my design is gonna fare. Here are the particulars:
4 layer board (from the top: ...
1
vote
1answer
231 views
4-layer board in PCB Editor - do I need custom vias?
I routed a 4-layer board using the default via. When I put in my ground and VCC planes the vias had no clearance. How do I fix it? Do I have to make my own vias? (I thought it was automatic). Next ...
6
votes
1answer
362 views
How is my crystal layout looking?
I've done a preliminary layout of my crystals. I've never designed a board with crystals so this is just a rough first pass based on my small set of working knowledge of crystal layout. How am I ...
1
vote
1answer
581 views
Print a PCB layout several times in the same sheet at once in Proteus
How can I replicate my layout so I can print several of them in the same sheet without having to do it manually (printing one layout each time and setting its position relative to the previous ...
12
votes
2answers
696 views
The best stack-up possible with a four-layer PCB?
I'm designing a 4 layer PCB and I know that the standard stack-up is
Signals
GND
VCC
Singals
(GND and VCC can be switched depending on the layer with more signals)
The problem is, I don't ...
5
votes
1answer
109 views
Non-conductive pads in datasheet?
I'm designing a device which has a DM3CS-SF microSD connector and in the recommended land-pattern for the datasheet they have areas labeled as "Non-conducting traces". What am I suppose to do with ...
3
votes
3answers
521 views
Simplifying a relay network
I'm currently trying to design a relay network for a piece of laboratory equipment (PPMS). I would like to describe what the setup is, what I am doing now, what I hope to do, and how I hope to do it. ...
2
votes
1answer
186 views
Why do TQFP and TFQN have different advice regarding analog ground?
This question is in reference to How to split Analog and Digital GND planes for a TQFN device.
For the PSoC3, the advice on how to separate the analog and digital ground is different depending on the ...
1
vote
2answers
241 views
How to split Analog and Digital GND planes for a TQFN device
This question is in reference to Mixed signal PCB layout for PSoC.
If I am using a microcontroller which has separate analog and digital supply inputs and GNDs, what should do with the grounds?
...
5
votes
2answers
161 views
Do you think this board can be done in 2-layer or should I go to 4-layer?
Here are 3 photos of the board I am trying to build. The photos are the top, the bottom and the bottom with the analog portion (Buffer+ADC) inside a red box. It is an ohmmeter. Most SMD parts are on ...
10
votes
2answers
468 views
Mixed signal PCB layout for PSoC
I am developing a PCB for an analogue sensing application. It uses the internal ADC on a PSoC3. As usual, the application is very space constrained (11mm x 21mm), so I have had to make some ...
6
votes
2answers
330 views
Sawtooth traces on a PCB [duplicate]
Possible Duplicate:
Why wiggle nearby tracks on a PCB?
I was looking at a Raspberry Pi that a friend got today and noticed some weird traces on the board. I'm wondering why they were ...
8
votes
2answers
1k views
Placement of Vias to Connect Ground Planes
I've been wondering a lot about grounding practices on PCB layouts. My first question about it deals with vias. I've noticed that on a simple 2 layer PCB with ground planes on both sides, there will ...
9
votes
4answers
848 views
vias directly on SMD pads?
I was looking at an example board schematic provided by TI and I noticed something rather curious: vias were placed directly on SMD pads. Is this a normal/acceptable practice to follow? Or is it ...
7
votes
2answers
1k views
When to use ground plane cutouts?
I've been reading more about proper grounding techniques and using ground planes.
From what I've read, ground planes provide a large capacitance with adjacent layers, faster heat dissipation, and ...
4
votes
1answer
334 views
How should I isolate AC and DC on a small PCB?
I am designing a small PCB (1"x1") and it will have some DC logic traces (5V and GND) and some high frequency AC power traces (100V 1000Hz 50mA). Are there any special considerations I need to take ...
12
votes
1answer
2k views
Competing PCB Crystal layout recommendations
This is related to this question: How's my crystal oscillator layout?
I'm trying to layout a 12MHz crystal for a micro controller. I've been reading through several recommendations specifically for ...
3
votes
1answer
354 views
First time PCB design - board dimensions question
I'm designing a PCB for the first time and I'm using NI's Ultiboard software to do so.
I tried uploading my Gerbers to a few cheap fabrication services, but I've noticed one discrepancy: I don't ...
3
votes
3answers
377 views
How to find a footprint?
I have just started using KiCAD (with no other experience e.g. in Eagle). I was basically able to put together a schematic and layout a board but I am struggling with some footprints. How would I ...
12
votes
2answers
947 views
Termination resistors: are they needed?
For a project I'm designing, I'm using an IS42s32800 (TSOP) SDRAM with an LPC1788 (QFP) microcontroller. On the PCB I have 4 layers with a ground plane right below the top signal layer and a VDD plane ...
5
votes
1answer
215 views
Any pitfalls when going from two to four layer PCB?
I've had a couple of two layer boards made with success but my current design requires more layers. Can anyone suggest any pitfalls to be aware of for my first attempt, the price difference is ...
1
vote
2answers
255 views
What are thermals?
I was looking through various options available for Eagle CAD through-hole and SMD pads and I noticed a "thermals" option. The documentation wasn't much help in determining their function other than ...
8
votes
4answers
913 views
Best edge connector for my pcb?
I am making a PCB where the goal is to keep BOM as low as possible and also the cost to the lowers. It has proven to be quite a difficult task but I am at a final stage now.
My PCB needs to be ...
8
votes
3answers
791 views
Feasibility of PCB edge plating?
How feasible is it to edge plate a PCB or at least a portion of one? I've seen it done but as I understand the outer edge is only cut after plating at most fab houses. Is this something that's ...
5
votes
3answers
291 views
Questions with overhanging silkscreens in eagle cad
I am currently using several footprints in my pcb design which have tPlace silkscreens that extend beyond the board boundaries, and I was wondering what the implications of such silkscreens are since ...
2
votes
0answers
596 views
Library of footprints for Cadence Allegro / PCB Editor
I keep having to design my own footprints for Cadence Allegro / PCB Editor even for standard parts. There are lots of libraries for schematic capture symbols but I am having trouble finding ...
9
votes
1answer
434 views
A few questions about vias and pads on a PCB
I have been used to work with 1 layer PCB's and prototype boards. On the bottom layer are all the routes and the soldering , on the "top" layer are only the components.
Now, I am trying to work with ...
10
votes
2answers
779 views
Why are vias placed this way on a PCB?
I used to check complex commercial PCBs specially those of graphics cards to see how professional PCB designers do their layout and learn from their techniques.
When I checked the card shown below I ...
2
votes
2answers
252 views
Signal integrity at 40 MHz with parallel signals
I have to design a board with an 8 bit parallel port that carries 40 MHz signals. It is not possible to wire them very short and in parallel (I am sure the wires will be about 7 cm long), so I have to ...
4
votes
2answers
278 views
Routing considerations of analog signals on twisted pairs
I'm designing a part of a system that will receive 4 analog signals carried on 4 twisted pair cables which are input to an ADC. These signals are low speed (probably in KHz) bipolar ranging from -10V ...
2
votes
2answers
353 views
How can I meet these PCB design conductivity/isolation requirements?
The specifications required are as follows:
The resistance between ground pins on a connector and the case (chassis) ground should be less than 3 Ohms.
The resistance between any other signal on the ...
8
votes
4answers
910 views
How to indicate breakaway tabs in PCB design?
I'm designing two boards that'll always be used together. I'd like to place them both on a panel and break them apart after manufacturing.
I found a document on PCB CAD Design Guidelines that ...
10
votes
7answers
582 views
Naming (C1, C2, R1, R2…) components on PCB
I want to label all the components on my board C1, C2, R1, R2, IC1, IC2, etc.
I am trying to think about the best naming convention for everything. On one hand, I want to group together all the ...
5
votes
2answers
598 views
Eliminating Thermal Isolation Pads in Eagle
When creating a ground plane in Eagle, Eagle automatically creates a thermal isolation for the pad.
My first question is, does this isolation limit the current compared to a pad that is ...
0
votes
3answers
472 views
PCB part naming for LEDs
Usually when I design a PCB, I name the LEDs as LED1, LED2, ... , but now I'm working on a set of boards where I do not have ...
0
votes
1answer
309 views
Reducing cost by eliminating microvias when designing a PCB with buried vias
I'm designing a 4-layer PCB for a very small adapter from a BGA on one side to several discrete SMT connectors on the other. Due to space constraints, I cannot use through holes for some of the ...
1
vote
2answers
157 views
Recommended placement and routing of an RC Low pass filter
What are the recommended placement and routing techniques for the following RC low pass filter circuit:
I made an initial placement and routing that's shown below:
Actually it's randomly placed ...
6
votes
3answers
1k views
Should I isolate grounds of an isolated DC/DC converter?
If I use an isolated DC/DC converter, when designing the PCB, should I isolate the ground of the input and the ground of the output as shown below?
I've never isolated grounds (except for AGND and ...
4
votes
1answer
1k views
Difference between drill layer, hole layer, and milling layer in Eagle
What is the difference between the drill layer (44), the hole layer (45), and the milling layer (46) in Eagle PCB?
-3
votes
1answer
248 views
Masters of Science (MSc) for a PCB Design Engineer [closed]
I am a PCB Designer with 1.5 years experience (2010 grad) and I want to join a Masters of Science program to improve my knowledge in my field of work. Is it necessary to join a masters program? or ...
2
votes
1answer
388 views
How do I calculate the proper width of a copper trace based on a given gauge (AWG) of wire?
I am designing a PCB which I will etch at home, but I need to know how to convert a wire gauge into the proper corresponding width of a copper track on the PCB. Is there a standard formula for this?
17
votes
2answers
690 views
Why wiggle nearby tracks on a PCB?
I've been reading an article (TheMagPi eMagazine) relating to the Raspberry Pi; "An ARM GNU/Linux box for $25."
In the article, page 17 at the bottom it shows somewhere where a track zigzags next to ...
9
votes
6answers
1k 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?
2
votes
1answer
140 views
electronic freelancing website [duplicate]
Possible Duplicate:
Any reliable site where hardware engineers can be hired for small (work-from-home/telecommute) projects?
I want to outsource couple of industrial electronics circuit ...
6
votes
1answer
443 views
Eagle is refusing to tie ground pads of SMD components to the ground plane
So, long story short, I copied Eagle's standard RCL library to prune it down to the SMD essentials and to verify the packages. I removed the old library entirely, so it's not even loaded anymore, and ...
2
votes
1answer
248 views
8 layer PCB with Gold plating for each inner layer and immersion gold for all out layers?
it is just a 8 layers PCB with min line 4mil ,6mil holes in a 10 mil pads, Can somebody tell me why we need gold plating for each inner layer while immerison nickel gold for all out layers.
2
votes
2answers
243 views
Questions About PCBs
I understand what they are but i have a few questions...
What are the multi layers on a pcb (i understand 1 and 2 is front back but what about 3, 4 ,5 etc.)
In ...
5
votes
5answers
671 views
What is the behavior of an unprogrammed MicroController?
Problem:
I get Errors when trying to connect to the MicroController using the PDI interface. How does a MicroController behave when it hasn't been programmed? Is there a pin that will toggle to show ...
1
vote
1answer
99 views
Vias not visible after Eagle Cam Processor
I am trying to generate a printout of the PCB using Eagle Cam processor to get it made.
My settings are as follows:
Section: *
Device: PS
Style: pos. Coord and Fill pads are enabled
Layers: top, ...
3
votes
4answers
782 views
Autorouter for PCB breadboard?
Is there any usable program that could help me organize elements on PCB breadboards? Or maybe some kind of autorouter?
By PCB breadboard I mean something like this:
