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
53 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
47 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 ...
4
votes
2answers
152 views
Why Characteristic Impedance must be “50” ohms?
Where does this number came from?
For single ended it must be 50 ohm and for differential pairs 100 ohm. Why?
For PCB with controlled-impedance these are that common numbers. Outside of the PCB you ...
3
votes
2answers
117 views
Circuit version of a simple if else program
I have written a simple program that controls two motors (outputs) each with two states ( positive, negative) with an Arduino. The motors states based on the status of four buttons (inputs) (Up, Down, ...
1
vote
3answers
104 views
Cannot find SMD resistors in Altium
I just moved from Eagle to Altium. I cannot find SMD resistors in Altium libraries. In Eagle, there are almost all general components. In Altium there are only few resistors. Where can I download the ...
2
votes
1answer
45 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
147 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 ...
2
votes
2answers
106 views
Need second set of eyes on 555 50% duty cycle soldered protoboard
I'm a hobbyist trying to learn the basics of the 555 timer, and am working off of the 50% duty cycle circuit from the National Semiconductor data sheet for the 555 (PDF pg. 10 Fig. 14) and have ...
6
votes
2answers
124 views
Is it worth going to so much trouble with Ethernet differential tracks?
I am laying out a PCB containing an Ethernet connector with integral magnetics, and a Micrel KSZ8051MNL Phy. This is for a 100mbps application.
In an attempt to reduce EMI, and make the Ethernet data ...
6
votes
2answers
123 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
0answers
36 views
Altium: Query to target Vias in Pads
Does anyone have a Altium query/selector that targets vias in SMT pads? I'm routing a very dense HDI board, and would like to make rules that exclusively target vias that are inside a component pad ...
-4
votes
0answers
44 views
learning embedded system [closed]
can someone please assist me regarding :
1 The topics that i should read in electronics in order to learn designing schematics for embedded systems as well PC boards.
2 and reference book that i ...
3
votes
2answers
111 views
Return current in 8 Layer stackup
I have to design a multilayer Board (8 Layer). This is a part of 4 PCBs in a product with plastic enclosure. The high speed signal on PCB are Ethernet, USB2, LAN and UMTS integrated modem. Product ...
-1
votes
1answer
116 views
How to (re)create an USB 3 header interface PCB? [closed]
I would like to start a "small" project. Create an USB 3 version of an existing USB 2 PCB.
On the PCB there is only 2 USB connectors, a capacitor and a USB header (to connect to the USB controller). ...
1
vote
2answers
44 views
Connections of SPST switch-ESE-11SV1
I am using SPST switch as a digital input to my NXP MBED Module.I have done the design of the whole circuit in OrCAD Capture and Allegro PCB Editor.
the switch I am using is Panasonic's ESE-11SV1.The ...
11
votes
2answers
168 views
Low volume PCB assembly testing
I've ordered fabrication and assembly of small PCB batches (~100) a couple of times already. Each time, the assembly factory asked me if I wanted to do testing on the boards. Since I'm not a ...
4
votes
2answers
103 views
Returning Currents for two side boards and returning current questions
I have some questions these are I am not sure:
I have designed a board that has classical 2 side PCB design. Frequency is not a big issue for me but with ESD my CPU resets itself. (CPU clock 20 Mhz, ...
8
votes
2answers
246 views
What is the purpose of the square vias with no solder mask on this board?
This board from an electronic combination lock contains a curious mix of two types of vias:
Small round ones with green solder mask over the top.
Larger square ones without green solder mask over ...
1
vote
1answer
47 views
PCB Board design for H-Bridge TLE5206
I would like to make PCB board for TLE 5206-2G (check the datasheet).
It is TO263 package.
Basically, what i dont know is how to transfer heat out of the IC. I saw few PCB's that has little copper ...
-2
votes
4answers
176 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 ...
5
votes
3answers
175 views
Electrolytic capacitors connected with one terminal only?
I've got an ordinary PC motherboard. So, out of curiosity, I started looking at the power circuits on it and found several large 1000–1500 μF electrolytic caps:
It's easy to see that their cathodes ...
1
vote
1answer
64 views
DipTrace bottom layer pad shape
I'm having a problem in DipTrace. I'm trying to change the shape of the pads on the bottom layer. I have successfully created and had etched a similar PCB in DipTrace yesterday, and have followed the ...
0
votes
2answers
137 views
Impedance Control PCB design Help
Im new to impedance control PCB design and I got following information from a pcb manufacture.This is their standard stack and I'm planing to control impedance of my design according to their spec.Cos ...
4
votes
1answer
158 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.
...
2
votes
2answers
170 views
What can I do as a student to be a better candidate for a hardware design job? [closed]
If you were looking to hire a student still in school for an internship position at a high-tech company (say, Microsoft, Apple, or Google) for hardware design. What kind of skills would you be looking ...
0
votes
1answer
65 views
How do I lay out a 28 pin DIP socket pattern using GSchem?
How do I lay out a 28 pin DIP socket pin pattern in gSchem?
I imagine that I can lay it out manually but is there some sort of library component I can use?
VERSION: 1.6.1.20100214
7
votes
1answer
211 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 ...
8
votes
1answer
188 views
Is there a PCB-layout related reasoning behind DDR memory package and footprint?
BGA DDR packages have a unique footprint. There are two columns of pads on both sides of the device, and an empty column in between.
Is there a reasoning behind the placement of these pads (in ...
6
votes
1answer
164 views
How are these pcb pads made?
We want to design a pcb module that should be soldered directly onto customer pcbs (exactly like ICs ect.)
I found a module which does exactly that, please see pdf.
...
1
vote
1answer
83 views
Strange Eagle Copper Pour Issue
I'm experiencing an interesting issue with Eagle's polygon copper pour. As you can
see below, the solid red is the copper pour area, while the dashed line is showing the complete polygon outline (I ...
1
vote
2answers
138 views
Chip antenna mounting considerations
I'm using this chip antenna with a 868MHz radio (RFM12B): http://www.johansontechnology.com/datasheets/antennas/0868AT43A0020.pdf
According to the datasheet's mounting considerations there's a trace ...
-2
votes
2answers
200 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
109 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 ...
4
votes
2answers
136 views
PCB Design Considerations - Copper Pouring
So after a very long effort, I think I've finally come towards the end of my PCB board design. It's a two layer board with no ground or VCC plains (Re-routing is not an option) as I can't go though ...
11
votes
2answers
271 views
Techniques for placing components on PCB's
I know that placing components is quite an art rather than following some set of rules to get the job done, but I am looking for some references about the topic.
I already saw this tutorial and it is ...
3
votes
1answer
172 views
Need help with selecting an antenna for PCB
I have designed a pair of circuits which utilize the QAM-TX2-433-ND/QAM-RX2-433-ND transmitter/receiver.
So far everything is hooked up on solderless breadboards, with just a length of wire for ...
0
votes
2answers
279 views
First time PCB layout recommendations [closed]
I have been assigned the task of laying out an A4-sized 10-layer PCB board using Allegro. Someone else is doing the schematics, which I will receive soon (all I know now is that the board contains an ...
1
vote
3answers
153 views
11A trace width
Using this PCB Trace Width Calculator the external tace width for 11A (default settings) is suggested as 8.21mm.
Is this acceptable? I was expecting something bigger, and just wanted to check that ...
5
votes
1answer
404 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
126 views
In Altium how do you increase the trace width from a Pour to GND Vias and Pads?
In my PCB layout I have a ground power connector and several pads where I would like thick traces to connect to the ground plane.
When I use the polygon pour feature, it will connect these with 4 ...
2
votes
1answer
133 views
Put component designators on the PCB's silkscreen in KiCad
I'm doing my firs PCB design, and I've choose to use KiCad.
The problem that I'm encountering is that when I look at my board in 3D view, the components' designators does not appear to be on the ...
2
votes
1answer
105 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 ...
2
votes
1answer
153 views
Eagle PCB design Libraries?
I am doing my first Eagle PCB design. It's been going smoothly so far, however, I just hit a road bump. I am using a TC1269 Regulator, but cannot find the CAD library for it. I have looked into ...
1
vote
2answers
149 views
SSOP and SOIC standards
In theory at least, SOIC is half the pin pitch of DIP and SSOP is half again. Thus SSOP is 0.1/4 = 0.025" or 0.635mm. Except I see many parts, from TI and Linear especially, which are SSOP (or TSSOP) ...
7
votes
3answers
271 views
Crimping tool basics
When I design a printed circuit board, I often put 100mil male header anywhere. Sometimes I think it would be better to place some connectors for more reliability. Anyone here knows which ...
1
vote
5answers
207 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
236 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.
3
votes
1answer
264 views
In a boost converter, should ground plane be placed underneath the gate trace?
When designing the PCB layout for a DC-DC boost converter, one does not place a ground plane under the inductor, to prevent induced ground currents. Also, for SMD MOSFETs, the drain (switch node) ...
19
votes
6answers
909 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, ...
