Tagged Questions
3
votes
1answer
107 views
Are these pcb layouts good?
I'm working on an USB audio interface; the board has an analog section, with amplifiers and filters for the input and the output signals, a digital section, with the DAC, ADC, and the microcontroller ...
4
votes
1answer
61 views
Surface Mount vs. PTH Components For Production
I'm a hobbyist who has developed a product which uses ~20 PTH components. The device is essentially an Arduino UNO with some extra driver ICs and LEDs. I have had quite a lot of positive feedback on ...
-2
votes
0answers
49 views
pcb assembly already preroute [closed]
i have a problem with altium designer, i search to create a project with only one pcb and one sheet which brings together pcbs already preroute.
I already create several project and now I want to ...
2
votes
1answer
50 views
Eagle configure autorouter to solder components (except vias) only on bottom layer of double sided PCB
In double sided PCBs it is difficult to solder through hole components like IC bases, headers, etc. in the top layer. Normally the Eagle autorouter places the solder pads on both sides. That is, in a ...
5
votes
1answer
153 views
14 Layers Stack-up proposal
Could be this stack-up correct/appropriate for a 14 layer pcb?
The PCB includes a CPLD at 50 MHz and a Gigabit Ethernet transceiver at 125 MHz. Both mounted in Primary Component Side.
There are 4 ...
6
votes
2answers
135 views
Mains to low voltage seperation between FR4 PCB layers
I cannot find clear information on running mains and low voltage on adjacent layers on FR4 PCBs. I understand how much creepage distance to allow, but for example, can I run - 50Vdc, 240Vac, 0Vac, ...
-2
votes
4answers
179 views
Software to design a 2-sided PCB with discrete components [duplicate]
I'm quite new to PCB Fabrication. I have a circuit with discrete components on a breadboard. I would like to fabricate this circuit into a 2-sided PCB containing discrete components. Something like ...
4
votes
1answer
166 views
Heat Sink for SOT223
I am designing PCB a in which I am placing a BSP296 N-channel MOSFET, for switching solenoids:
MOSFET supply voltage is 24V
MOSFET max power dissipation is 1.8W
Max operating temperature is 150°C.
...
7
votes
1answer
218 views
Best place to place a decoupling capacitor
See this image which gives four options to place decoupling capacitors:
(from http://www.learnemc.com/tutorials/Decoupling/decoupling01.html)
I would say option (d) isn't good - I would recommend ...
-2
votes
2answers
201 views
Where can I order flexible PCBs? [closed]
Question
Where can I order flexible PCBs online?
Does such a service exist form which I can order complete flexible PCBs with components already soldered down? Where?
Background
I'm in the ...
1
vote
1answer
112 views
Eagle 6 : Problem Importing Custom Parts
Recently started working on a new PCB board for a dev kit. I ran in an issue where I had made a custom part for the M50-3501042 2x10 male header with 0.05'' (1.27mm) pitch.
Note also that this is a ...
5
votes
1answer
429 views
PCB Ground and Power Planes
I am desigining a 4-layer PCB with the following stack-up: Signal Top, Ground Plane, Power Plane, Signal Bottom.
This is the first PCB I make like this, which includes a noisy SMPS with a switching ...
2
votes
1answer
106 views
Eagle TI CC2540 Ground Pad?
I have been working on a PCB layout. It's my first time working with Eagle, and my first time prototyping a board. I am using a CC2540. I understand that this uses a RHA package which has a ground ...
1
vote
5answers
208 views
PCB Prototyping and Fabrication
I have been working on a project for the past four months. Most of my development have been on breadboards and prototyping boards. I am now in the stage where I want to get a PCB printed and ...
0
votes
1answer
244 views
6-Layer Stackup for PCI express design
I'm pondering over a stackup for a 6-layer board using a couple of PCIe connected ICs.
My first idea was to use the following Stackup:
Signal
GND
Power (Multiple power supplies, so it's a split ...
0
votes
2answers
95 views
Buried via annular ring size
How do you decide the minimum annular ring size of a buried via?
I remember to have seen one manufacture list this, but generally I can't find the size on manufacture websites.
19
votes
6answers
922 views
Can we build capacitors on a PCB board?
For the magnitude of nF or µF capacitors, I hope I can build them on a PCB board. The capacitor is like a two metal layer and something between them.
Is this possible?
Not buying the capacitor, ...
5
votes
1answer
235 views
How good is my xtal design on my pcb?
I'm designing a board for a school project using eagle. I thought I could get away with using the onboard clock of the PIC18 since it's not doing a whole lot (mostly just LEDs), but one of its tasks ...
3
votes
3answers
337 views
What are the important design considerations when laying out a PCB? [closed]
After filling a bunch of breadboards with some successful experiments, I'm ready to start making PCBs and I'm wondering if there are any design considerations of which I need to be aware?
Some PCBs ...
3
votes
1answer
72 views
Editing embedded components in Eagle
I got a PCB schematic and layout in Eagle format from a website and I want to edit the dimensions of components. Since everything is embedded inside the PCB layout and schematic, I find it difficult ...
1
vote
0answers
97 views
What is this program called and where can I learn about it?
I've seen a video of someone who created an intelligent waste bin. It could catch objects you threw at it by observing thrown objects with Kinect and driving at the location of impact (YouTube).
He ...
3
votes
2answers
436 views
PCB Trace inductance
I am planning to do a high current (200A+) PWM in a PCB and I am afraid the PCB traces inductances will be a huge problem...so I have some questions:
1- How may calculate the trace inductance?
2- As ...
6
votes
2answers
845 views
Castellated/Edge-plated PCBs: Comments on Mechanical/Electrical contact reliability
(This is a follow-up to this related question).
I'm interested in some feedback from people's design results/experiences with Castellated PCBs as a method of attaching one PCB to another. By ...
9
votes
5answers
505 views
Ideas for attaching / connecting / stacking one PCB onto another with no gap
What methods might be feasible for attaching/stacking one PCB immediately on top of another PCB, with the following conditions:
Zero spacing/gap between the two PCBs
Electrical contacts are needed, ...
0
votes
0answers
127 views
Merging two PCB boards [closed]
I have a PCB board from an all-in-one computer I want to be able to use with a spare laptop motherboard. The PCB button board has momentary switch and 3 square LEDs for the power on indicators as ...
2
votes
2answers
295 views
Is case grounding compulsory in typical 32.768kHz crystal for Real Time Clock?
Pictures shown below is a typical 32.768kHz crystal, commonly use in Real Time Clock circuit (e.g: DS1307 & DS1337)
Referring to an earlier question posted here, it is a good practice that ...
7
votes
5answers
2k views
What is the usage of Zero Ohm & MiliOhm Resistor?
I am new to PCB design and I noticed that some schematics use 0Ω or 100mΩ resistors. What is their purpose and why do we need to use them in our PCB design?
Normally if we wish to probe how much ...
3
votes
3answers
599 views
Best order for PCB power planes?
[EDITED]
I seem to have confused the terminology between signal and power planes! There is a ground plane, plus potentially four power planes -- +/- 15V, +HV (200V), and i'm not sure if a -VREF (~ ...
5
votes
3answers
328 views
CAD Schematic pin arrangement approach
I was looking for related questions here, and the closest one I could find was this one: Industry Practices for Schematic Design?
However, it does not address my specific question, so here goes: I am ...
6
votes
5answers
597 views
Ideas to stack multiple PCBs on top of each other?
My design has a number of boards stacked on top of each other. I would like to connect signals across the boards. The boards all need the same 10 signals running through them (all boards from top to ...
1
vote
2answers
141 views
What would be the best approach to align a photomask onto a PCB panel?
Issue: Alignment of photomask to reference holes drilled
When making PCB in panel form, the reference holes are usually drilled at 4 corners of panel to allow alignment of photomask to the PCB board. ...
7
votes
2answers
1k views
What are the advantages of having two ground pours?
I've seen many 2-layer PCBs that have a ground pour on both the top and bottom layers, I was wondering why do that ? and wouldn't it be better to use the top layer for power and signals and the bottom ...
4
votes
1answer
670 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 ...
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 ...
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 ...
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 ...
9
votes
4answers
849 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 ...
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 ...
12
votes
2answers
948 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 ...
8
votes
3answers
793 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 ...
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
781 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 ...
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 ...
