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.

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4
votes
1answer
48 views

Eagle: polygon pour leaving funny blank areas

I am doing ground pours on both the top and bottom side of a two-sided board. The top side fill seems to work fine, but the pour on the bottom layer is leaving a bunch of odd shaped blank areas (see ...
2
votes
2answers
59 views

Can ground plane EMIT noise?

I have 3 separate grounds in my project: AGND - Analog ground is very quiet, very small relatively smooth currents PGND - Power ground used for power bypass caps and power supply related circuitry ...
-1
votes
1answer
94 views

Help I'm New to PCB design and would like a review [on hold]

Help I'm New to PCB design, and I think my board has problems :( I am designing it with circuits.io and 123design. I think the holes are too big for a normal soldering pin. I am trying to connect ...
3
votes
6answers
617 views

Why are there no easy-to-solder SMD diodes in 0603 packages?

What seem to be the most popular SMD diodes currently come in SC-79 packages, but they super tiny and really hard to hand solder... ...and they also can be a hassle even for reflow. So I thought ...
3
votes
1answer
30 views

Differing Hole Notations In Eagle CAD?

I was just creating some vias in Eagle and was playing with the drill diameter, and for some reason Eagle seems to put differing notations around the hole when the size changes, is there any reason ...
0
votes
1answer
77 views

PCB lab equipment

I was thinking of buying parts to make equipment for PCB production. I have the knowledge and the experience with PCB production from school (about 10 years ago), but I have no knowledge about the UV ...
1
vote
2answers
45 views

Altium Microstrip routing

I am currently trying to route a micro strip for a GPS and GSM antenna on Altium which got some constraints on spacing with ground poured plane like the one shown just below: This is currently my ...
0
votes
1answer
45 views

MCP16301 Step Down Voltage Regulator PCB Layout Validation

I'm looking for some feedback/validation that the layout for this MCP16301 is correct. I'm trying to get 600mA 3.3v Out from 12 input. I'm using the circuit as described in the datasheet on page 23 ...
0
votes
0answers
35 views

Altium trace length vs signal length

I've seen both of these in the PCB tab when editing the PCB board in Altium Designer.. what are the two? I thought I new, but I have fully routed traces with signal lengths of 0 as well as signal and ...
1
vote
1answer
70 views

Draw routing on PCB without components

Is there any way to draw routing on a PCB in the software PADS Layout without any components, like the CAD images below? If PADS Layout doesn't work, does Eagle have this function? Also, can I resize ...
3
votes
1answer
61 views

RF microstrip track parameters calculation

I am currently finishing the design of a board where there are two antenna microstrip on the surface of the top layer. I have a 4 layer PCB. I use FR4,so I suppose dielectric is 4.6. Thickness of the ...
0
votes
1answer
73 views

Why are circuit boards not covered in thermal paste?

A pcb in deionized water may behave differently due to the change in capacitive ratio (leaving obvious problems such as where to get pure deionized water and keep it contaminant free). However, ...
1
vote
2answers
76 views

Decoupling and bulk capacitor number and value

I am currently finishing a circuit with TIVA C TM4C123G where the user manual indicate the following: "decoupling capacitor typically 0.1uF in value and should be accompanied by a bulk capacitor. The ...
-1
votes
1answer
75 views

Reduce dev board schematics to custom board for production [closed]

There is already a post on here that is very insightful and related to my question "go from dev board to production board". However, I need a lower level understanding of schematics. I've searched the ...
0
votes
1answer
51 views

How to decide and calculate parameters for track on differential pair?

I am a bit lost about how to establish the parameters to establish differential pair routing. I am currently trying to route several differential pair and I am a bit new to this. I have searched ...
0
votes
2answers
51 views

when modeling a component, do you use the top or bottom view?

I'm modeling a component from this datasheet, they provide both a top view and bottom view of the components seen below, does my pcb footprint represent the top view or the bottom view? This has been ...
3
votes
6answers
713 views

What is the purpose of a tri-state pin in a Oscillator

I'm trying to interface this clock (32.768kHz Ceramic Surface Mount Crystal Oscillator datasheet), but I'm confused as to what to do with the tri-state pin. What is it's purpose in the oscillator and ...
6
votes
3answers
342 views

How do you document bodges?

After making the PCBs, we decided on some bodges and implemented them on the PCBs. What's the standard way to document that on the schematics? For now, I hand drew with the mouse, paint style, on ...
-5
votes
3answers
47 views

Differential pair how to decide track width, spacing and lenght matching [closed]

I am currently routing a pcb where there are some differential pair: Speaker, Mic. How do I decide what should be the space between both tracks and what should be the width for the traces ? I add a ...
0
votes
1answer
39 views

Order of Physical Proximity for Decoupling Capacitors

I have completed a schematic for a PCB and selected a series of decoupling capacitors for usage with a variety Xbee format radios on one board (i.e. one at a time, but changeable). I have included in ...
0
votes
1answer
99 views

Does this circuit look proper?

We have to draw 3A in peak bursts, so I computed 55 mils wide for this amount of current. The footprint on this drawing is of a transistor, that has a small footprint. Would it be best to keep it this ...
0
votes
1answer
58 views

Weird value of track width with calculator

I am currently working on a design where the power input will be connected to battery of car. I have a series of LDo and DC-Dc but the entry point is 9-36v and I am unsure what the current can be . I ...
1
vote
1answer
67 views

Power supply positioning in PCB design

I am currently routing a PCB. I have several chip and several LDO and DC-DC to power those chips. I am shared between trying to group all those LDO and DC-DC in one area of the board (in the corner) ...
1
vote
1answer
77 views

Designing PCB in KiCad

I'm trying to do my first PCB in KiCad and came across a few problems. Here is how far I got: My questions are: 1) The LM358 socket and the capacitors I put do not have holes. Only the resistors ...
-1
votes
2answers
91 views

Is length matching is necessary on I2C, UART signals, and SPI? [duplicate]

I am currently designing a board where there is a UART, as well as SPI and I2C, should I length match or take care of differential pairs on those interfaces?
0
votes
0answers
21 views

Assigning LED in the schematic capture to a package in proteus

How to assign LED's in schematic capture in the proteus in to a package inorder to use it in the PCB layout. I am designing a sensor board for a line following robot. I designed it in the schematic ...
1
vote
2answers
44 views

Interfaces with differential pairs during PCB Design

I was wondering where I could find a list of interface which require differential pair or particular design rules ? I know for example that USB require different pair routing. I identify them because ...
0
votes
1answer
50 views

designing trace anthtenas for 2 sets of rf rx+ tx

First of all forgive me for my mistakes, English is not my main language. I want to design a custom pcb (i'm not an expert just a hobby), I have a working breadboard circuit of an micro controller ...
3
votes
2answers
133 views

What is the source of this shape on my USB eye diagram?

I have designed a USB device around an STM32F105. It is USB 2.0 Full Speed CDC device configured as a Virtual COM Port using ST's USB Library. It uses the STM32's built-in PHY, and runs at 12 Mbps. ...
2
votes
5answers
118 views

Bypass capacitor placement

I have the current schematic with a full line of capacitor which I suppose are by pass capacitor. As you can see the schematic show a unique point of connection on the 56 pin however I suppose that ...
0
votes
1answer
25 views

Capacitor for TF CARD placement on PCB layout

I am currently laying out a PCB where there is a TF CARD on it. The schematic is as below. I have this capacitor to place which I suppose might be a decoupling by pass capacitor, so unless my mistake ...
1
vote
1answer
82 views

PCB layout and testpoints

What are your personal policies for selecting which nodes should have testpoints? Can a testpoint be used as a node for powering a circuit? Does a testpoint on a line create a stub, subject to ...
1
vote
2answers
58 views

PCB layout ideas for multiple voltage power lines

I am new to designing PCB boards. I have been working on a data acquisition board and it seems that four layer board will be correct way to go about it. But there are a lot of different voltages ...
-1
votes
1answer
36 views

How to set required spacing between two connectors pad on eagle cad soft?

I have 2 pin screw terminal in my project like this one. But I can't find screw terminals with 7mm spacing between it's 2 pins in eagle library. So, I have decided to use pinhead library to create 2 ...
0
votes
2answers
88 views

Could electromigration cause a short circuit in a PCB

Is it possible that electromigration cause a short circuit in a PCB? Theoretically due to chemical potential difference between gold and nickel (1.68 V) it's known that metal ions can penetrate into ...
12
votes
3answers
670 views

how should I label components changing between PCB versions?

I have a current version of my PCB, and I'll make a new one where I will delete some resistors here and add some more there. What's the common rule for numbering? Should I re-use the numbers of ...
1
vote
1answer
28 views

Unrouted wires double after routing in eagle

I almost finished routing a PCB but after trying to change the placement of a via to ground plane ripup and route the wire connected to it, I've got a weird airwire which is between a pad and nothing. ...
-2
votes
1answer
99 views

I want to create a custom LED segment display. What do I need to study? [closed]

I want to create and then order a small run of a customized mass-produced LED segment displays for an art project. They will use PWM. It is not much more complex or detailed than a 7 or 16-segment ...
6
votes
3answers
706 views

PCB cutout specification

I want to specify a square cutout in my PCB, to fit a sensor module. The cutout must be very tight, that is it should only be 100μm wider than the sensor on all sides, as it is used to hold the ...
0
votes
1answer
32 views

How do i make sure that PCB traces or Enclosure unit is not affecting the BLE 4.0 range?

I am using BLE 4.1 ready module having on chip antenna, according to datasheet i have taken care in PCB layout design that at least there should be 8 mm of distance from Antenna and copper traces from ...
6
votes
6answers
696 views

Designing a PCB layout without having a schematic diagram (or netlist)?

Could you please let me know if it's possible to design a PCB layout without a schematic diagram? I outsourced the development and manufacturing of the ARM board which has 512MB DDR3 RAM and 4GB ...
4
votes
4answers
243 views

VCC pour and decoupling capacitors on a dual layer board

I am designing a simple dual layer board which has some ICs that I have to put decoupling capacitors near them. Initially I wanted to make both top and bottom layer as ground plane and route signals ...
1
vote
1answer
33 views

EAGLE: Placed bitmap on tStop

By accident I placed an imported bitmap on tStop instead of tPlace. How can I remove it? Unfortunately I noticed it too late to simply undo it.
0
votes
1answer
95 views

Why are there unconnected exposed pads on PCBs [duplicate]

I've seen this in several designs. What purpose do these serve?
3
votes
2answers
51 views

Interactive Diff Pair Length Tuning Altium Designer

I am using Altium Designer and sometimes (very often) when I am using the Interactive Diff Pair Length Tuning even when I click properly on the wire I have this error : As said in the response below ...