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.

learn more… | top users | synonyms

3
votes
1answer
61 views

Ground and power PCB layout for MCU

As you know most of the MCU's has several Vdd and Vss pins. In the case of two-layer PCB it seems convenient to use some polygons beneath MCU (like on the figure below). The first option is treat the ...
0
votes
1answer
65 views

PCB Trace Orientations [duplicate]

When inspecting a PCB earlier today it occurred to me that all traces you find on modern PCB's are confined to 45 degree increments with respect to the (typically square) board edges. What is the ...
6
votes
8answers
511 views

How do you cover up exposed high voltage pcb traces?

This is my PCB: The thick lines should be able to pass a high voltage (230VAC) signal through it. The board will be kept inside a enclosed box. In my case, the signal on the board is only one ...
-2
votes
1answer
26 views

Exporting from Altium to CST PCB Studio

Based on CST website, they claim that CST PCB Studio can import Altium files. But when I open Import on CST , it gives me just these options : I tried to Export Altium to HyperLynx and Import it ...
2
votes
1answer
34 views

Altium polygon pour doesn't cover same net pads

I've made boards and seen more that use polygon pours that flow over pads that connect to the same net. However, I was tasked with making minor changes to an old board that I didn't design. On the ...
0
votes
2answers
74 views

How to create rectangular holes in ARES?

I bought this three phase rectifier from local store and it has rectangular connectors, Now I need to make its package on the ARES, but I cant figure out how to create rectangular holes in the ...
1
vote
0answers
43 views

Ground loops on single trace in the middle of a ground plane

I'm trying to optimize the layout of a MAX1979 TEC driver on a double sided PCB. Is the placement of single, small traces in the middle of a ground place, as seen below on the bottom side of the ...
3
votes
1answer
166 views

PCB design: the setting of the test point and the use of variable resistor

I am designing a PCB circuit and meeting two problems: My design includes a two-stage MFB band pass filter. To make sure the center frequency of the filters is the same, I need to add a variable ...
0
votes
1answer
37 views

Arduino Ground reference plane

There are three GND pins on the Arduino UNO pinout. As I'm trying to design a mixed signal PCB to act as an Arduino Shield, I wonder how I should connect those pins, i.e. to the analog or digital ...
2
votes
1answer
52 views

How does Altium Designer's “impedance constraint” feature work?

Altium has a design rules option for setting a track width constraint according to line's impedance (e.g.; 50\$\Omega\$). How do I use it? Please give me instructions or a link to an online tutorial. ...
4
votes
3answers
164 views

Solder blobs on PCB traces and vias

On several PC motherboards, I've noticed some solder blobs on traces and vias. What's the deal with that? Are they some kind of test points? If so, how are they used?
0
votes
1answer
66 views

Trace aligment in a double sided PCB

Are there any layout requirements/special considerations when routing traces on top and bottom layers of a double sided PCB, e.g. angle between traces, can traces pass beneath an IC, etc? I know that ...
3
votes
0answers
53 views

how to convert files from Cadence to Eagle CAD?

Is there any free software that can convert Cadence files(.dsn, .opj, .brd) into Eagle CAD files (.brd, .sch)?
1
vote
1answer
84 views

Proper PCB grounding with several general purpose ICs

I'm designing a general purpose Arduino shield pcb and right now I'm struggling to find a proper ground layout. ICs on the board: 12->5V and 12->10V @5A switching DCregulators, several H-Bridge motor ...
3
votes
3answers
265 views

50MHz SPI PCB routing, use vias or resistors?

I am trying to route the SPI between MCU and ADC. However, the pin orders between MCU and ADC are not matched, there are crossings. A four-layer board is used.(signal - ground - power - signal) I ...
0
votes
1answer
77 views

How should Ground vias be placed?

I am using vias to filter the input power. The following to pictures show two ways of placing vias. I think both of them are inappropriate since the vias are not "fully" connected with ground through ...
0
votes
1answer
56 views

Analog/Digital ground vs Power/Signal ground

Are these ground plane separations on a PCB equivalent, or if I am already separating my ground into analog and digital parts should I also divide it in power and signal areas?
1
vote
2answers
89 views

Analog and Digital Grounds on a DAC

I've read at several places (1,2) that ICs such a DAC have both analog and digital ground pins, both should be tied to AGND at the chip. However, the specific part I'm planning to use (MAX5104) does ...
4
votes
1answer
67 views

Calculating differential PCB traces - Edge-Coupled Microstrip

I finally have the microstrip characteristic impedance thing figured out. But now, of course, I need to learn about differential signalling on PCB traces. I've spent some time researching. Here is ...
4
votes
2answers
134 views

Should I keep the decoupling capacitor's vias isolated from ground fills?

I'm finishing up a PCB layout which contains a 6.5 GHz ultra-wideband transceiver with a chip antenna, an ARM controller running at 72 MHz with a 12 MHz crystal, a 16 MHz SPI bus with 3 peripheral ...
2
votes
2answers
165 views

Dimensions of TQFN-EP 48 lead package

I'm looking for the correct pcb footprint for the MAX1979 IC by Maxim, supposedly in a TQFN-EP package. While the land patterns are available on Maxim's website, there are apparently several 48 lead ...
2
votes
2answers
147 views

Learning PCB Layout Strategy

A number of projects I have been working on have outgrown the breadboard phase, and I have been learning how to do PCB layout. My first tiny project (a cable adapter) went smoothly, but as I have ...
24
votes
11answers
5k views

Why do we need so many transistors?

Transistors serve multiple purposes in an electrical circuit, i.e switches, to amplify electronic signals, allowing you to control current etc... However, I recently read about Moore's law, among ...
3
votes
2answers
137 views

Power origin and power planes placement on PCB

Although there are many similar questions to this one, I wish to get your attention to this specific board layout. The main power on the board will be 5V, and one of the layers is dedicated for ...
1
vote
4answers
302 views

Duplicate pins on an IC

I've realised that several ICs with simple components, such as the FDS6690, provide duplicate pins in order to comply with a standard IC package (e.g. SOT23). My question is - are these pins connected ...
0
votes
1answer
57 views

Ground type for DC regulator

When considering a simple DC regulator such as a Texas' LM22677 on a PCB, should it use the digital or analog portion of the ground plane? EDIT: Contextualizing, I have a 12V input feeding two ...
0
votes
1answer
54 views

Ground separation

I'm designing a small PCB for low-level light detection. It contains an Avalanche Photodiode (APD), the DC regulator required for proper biasing (from 5V to ~65V) and a transimpedance amplifier. My ...
4
votes
2answers
199 views

Decoupling with multiple caps per pin. Which should be closest?

I have an Ultra Wide Band transceiver with an internal power amp. This PA has two input pins for Vdd. According to the manufacturer, each of these pins should be decoupled with three caps; 10p, ...
7
votes
4answers
700 views

4 layer PCBs with Fritzing

Can you use Fritzing to create a 4 layer pcb? Also, in real life, what is the maximum limit of layers we can use to create pcbs? is it 4 layers?
5
votes
1answer
166 views

DDR bus design review

In our last build we had issues with DDR stability in our prototype, simply because of lack of experience with this type of high speed memory connections. We managed to get it working with halving the ...
2
votes
2answers
147 views

How to determine annular ring width for thru-hole pads?

When placing thru-hole components on a PCB, how do you determine what the annular ring width should be? For example, I'm making a PCB with a thru-hole switch whose contacts are 1.2mm in diameter. To ...
2
votes
4answers
175 views

Should mounting holes be plated?

When putting mounting holes for screws on a PCB, should the holes be plated or unplated? I've read plating the holes provides better support for the screw and helps prevent the PCB from being ...
1
vote
1answer
67 views

Which Eagle part to use for this 2-pin Screw Terminal?

This is my first EAGLE design and I'm looking to add some a number of 2-position screw terminals (3.5mm pitch) PRT-08084. Problem: I can find the EAGLE part for ...
1
vote
2answers
104 views

Layout of 4 layer PCB - pour?

I'm working on a 4 layer PCB with internal 2 layers being power and GND... 2 outside layers are signal. Is it better to have a pour on the outside layers or just leave them empty except for the ...
2
votes
1answer
69 views

How to route to a hidden pin in Altium

I'm using Altium Designer 14.2.3 and I have a connector on which are always two pins connected to each other. In my schematic library I have configured the Pins to be hidden and connected to the ...
5
votes
3answers
140 views

Should you try and minimize via quantity?

I have a 6.5" x 4.5" double sided board that is mixed analog and digital. I have partitioned the analog and digital grounds from each other and have zero ohm resistors that bridge the two grounds ...
7
votes
1answer
167 views

What is “flush mount socket” in this 40yr old Tek scope?

EEVblog Dave shows us flush mount socketed IC's in this Tektronix 213 Portable Oscilloscope teardown, but it is hard to see and understand what exactly is a flush mount socket. Can someone explain how ...
9
votes
3answers
649 views

Does a pin jumper adds noise?

When designing a PCB, is it sensible to use a pin jumper in the pathway of a small current signal (around 0.8 uA) or could there be issues with noise? I would use the jumper to select between ...
1
vote
0answers
33 views

How to specify milling in gEDA pcb

I have a panelized board that I would like to put some nice, rounded corners on, is there a way to specify this so that the g-code can be automatically generated?
1
vote
0answers
35 views

How to create a footprint with a pad on the component side in gEDA pcb

I've read a bunch of tutorials, but can't figure out how to do this. What I want is a pin where the pad is on the component side instead of the solder side and the hole is plated so that it can be ...
0
votes
1answer
48 views

adding limiter to reduce distortion in audio amp

I got this schematic from adafruit. But at high volumes, it exhibits distortion. A guy from Maxim Integrated referred to include a diode-resistor network(BAV99 and R-100 Ohm) b/w C22/C23 and R8/R9(to ...
18
votes
4answers
528 views

At what frequencies does PCB design get tricky?

I have designed many mixed-signal PCB's where the highest-frequency component is the microcontroller's crystal oscillator itself. I understand the standard best practices: short traces, ground ...
1
vote
1answer
48 views

Terminating SDRAM on opposite side of board

I have a 4-layer board with the micro and sdram on opposite sides, the ram signals are short, but I still want to terminate them (I can test the board later and determine if I really need ...
0
votes
1answer
121 views

Zener diodes Eagle library

I need to make a PCB, and the only software I have is Eagle. All the other parts are listed in my libraries, but where can I find a library that has DIODES INC. - MMSZ5226BS (Zener diode)?
1
vote
1answer
54 views

Thermoelectric cooled Avalanche Photodiode sensor PCB

I'm designing a small PCB (max 5x5 cm) to bias and readout from an Avalanche Photodiode. Since the APD response varies greatly with the temperature, I want to use a cheap 12706 TEC together with a ...
0
votes
0answers
66 views

PCB- Vias to bypass inner layers

I am using kicad to make a four-layer PCB board. Signal Ground Power Signal I need a via that goes all the way from top layer to bottom layer. I don't want the via to get connected with the ...
7
votes
3answers
319 views

When is it OK for connectors to be SMT instead of TH?

A lot of boards with predominantly SMT components have TH connectors on them for things like headers and power connectors. Take a standard barrel power jack for example: TH: SMT: When designing ...
2
votes
1answer
61 views

'Not Mount' on PCB Design

I am referring to CC2531 reference design from TI (http://www.ti.com/tool/CC2531USB-RD) In the schematic diagram (and in the BOM), it is saying ‘ Not Mount’ for some components (resistors, capacitors, ...
2
votes
2answers
189 views

Tips on routing multiple powers(+5/-5/+15/-15/3.3 and etc. ) for a four-layer PCB

The most tedious thing for me while routing PCBs are the powers. I have made several PCBs of these kind and it seems that I have not learned much from the process. The power connections are always a ...
5
votes
3answers
505 views

PCB fabrication vs PCB assembly

What is the difference between PCB fabrication and assembly? Some companies like Golden Phoenix list that based on the size of PCB, it outputs a quote. Mine was 2.1 x 1.6 inch. It outputted 29 pieces ...