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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1answer
35 views

Adding voids underneath analog signal for improved impedance matching

Using a snapshot of an eval board design below as an example, voids are added to the ground plane on layer 2 (green) right underneath the analog signal path on layer 1 (yellow). This causes the analog ...
5
votes
1answer
660 views

Why are there slots around the transformers in this PCB?

I took apart an office printer a while back and this is a photo of one of the power delivery PCBs: (Please note I have removed some components from the PCB). What is the reason for the slots in ...
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0answers
18 views

Altium Designer 16 - corrupted library error

I've facing an issue with PCB Library and i don't understand how to solve. The system stops working and loading projects. A dialog box appear with an Error on corrupted library. I've tried to restore ...
2
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0answers
51 views

LM4510 Switching Converter not working

I am using a TI LM4510 converter (datasheet) to step up from 5V to 12V (adjustable). I have good input power, enabled chip, and followed datasheet, but the output voltage is actually lower than the ...
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2answers
51 views

PCB Through Hole Pattern for Non-Standard Wide DIP-6

Should I use a 2.75mm pin pitch for this Fairchild MOC3023TVM, or should I stick with 2.54mm(100mil) spacing? Notice the alignment on the dimensions from the datasheet in the figure below (2.75mm = ...
2
votes
1answer
58 views

Searching for exotic SOT23 P-channel mosfet where source drain swapped

Due to an error in the layouting process a batch of PCBs has to be scrapped. Instead of the standard pin assignments: 1 - Gate 2 - Source 3 - Drain we used: 1 - Gate 2 - Drain 3 - Source As a ...
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0answers
12 views

CNC 2020B - CNC USB Controller Setting File [closed]

I'm trying to configure this CNC 2020B machine to work with CNC USB Controller and with first run I managed to get tiny board printed from Gerber file, so my first mistake was using mm instead of ...
2
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2answers
56 views

Junction between curved and straight edge in KiCAD

I have a round PCB with a tab that extends outwards for a connector. I am unable to get the outside lines to properly resolve and connect together at the ends. Here is an image of the complete board ...
1
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1answer
54 views

TSOP-54 Adapter for prototyping

I am using an ARM M based development board (1) from TI. I wish to extend RAM (from default 256KB to 256 KB+ 8MB)by following the provided reference design (2). The design uses an ISSI DRAM ...
0
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0answers
37 views

How to properly develop a PCB everytime without taking too much photoresist off

Its been a while since I made a good PCB and I can't remember what I did to make it perfect, but after reading various resources, I have determined the following as to why most of my design was ...
2
votes
1answer
48 views

What is the pad size required for this BGA AW H3 Chip?

I'm trying to figure out the pad size to use for my footprint according to this datasheet.The last page in the datasheet has the package dimensions. I've also posted the relevant information in a ...
2
votes
3answers
59 views

How to connect PSU to these PCB pads

I have the Maxim Integrated evaluation kit for one of their chips (MAX14830EVKIT), and would like to understand what the intended way is to connect the two PSUs (24V and 3.3V, both 100mA) to this PCB. ...
2
votes
3answers
104 views

How to choose trace width for very high current PCB?

I am currently designing a PCB layout for my team's high current, high voltage project and am having trouble with choosing my trace width. The circuit is composed of 12 inductors placed in series ...
7
votes
1answer
133 views

How practical are these land patterns for connecting components in a SMPS?

Was reading this app note from Linear Technology: PCB Layout Considerations for Non-Isolated Switching Power Supplies and on page 7, there is the following image. Are the desired connections ...
5
votes
1answer
652 views

Why does 64 bit PCI have 2 notches?

From this paragraph, I understand that the reason for putting a notch on a 32 bit PCI card is simply to prevent people that doesn't read the specifications from frying their cards. In other words, ...
5
votes
1answer
136 views

Data Sheet Interpretation - “Insulation Area” and mystery Symbol

While creating a (my first) device package for this Micro SD socket in CadSoft EAGLE I stumbled over the inclusion of an "insulation area" in the recommended pcb layout: I'm guessing this is ...
0
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1answer
23 views

understanding DRC errors in ares proteus

i'm new to PCB and this my first printed circuit , i cannot understand what the DRC error is telling me , could you help to better read the error log and also help me with this error
1
vote
1answer
51 views

DC barrel jack datasheet dimensions!

I am using pj-102ah dc barrel jack. I am not sure if this is a mistake in the dimensions, or you can correct me if I am wrong. the top left red circle shows the the length of the three pins which is ...
3
votes
2answers
88 views

SMPS PCB Layout

I am using a couple of SMPSs (MPM3610) on a 4 or 6 layer PCB. The recommended PCB layout seems to use solid copper regions to connect the design together. Should thermal-reliefs be used on the ...
1
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2answers
83 views

High Speed PCB impedance question

I am going to design a high speed digital design including an FPGA and GSPS A/D interfaced with multi-gigabit/s serial ports. But I have found the impedance matching problem a little confusing, My ...
0
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1answer
55 views

DC barrel jack layout

1) I am using this DC barrel connector in my PCB and I want to make sure that when connecting a Center-positive power supply, my positive pin will be (1) and my two negatives will be (2) & (3), am ...
1
vote
2answers
41 views

How to connect VCC and GND conections of buffer 4050 on eagle?

I am unsing a 4050, the schematic usues the triangle representation. I have added a VCC and GND connectors to a power supply of 3.3V in the schematic hoping eagle recognizes the connections, but the ...
3
votes
0answers
27 views

IPC Specification for pad width vs. pin width (SMD)

I am working on a board that has a fine-pitch component (0.35mm). Each pin is 0.15mm wide. I received a question from the manufacturer asking if they could adjust the pad width from 0.22mm to 0.18mm +/...
1
vote
1answer
35 views

Altium ring shaped pad

i'm trying to create an airtight soldered mount for a pipe on a pcb depth sensor board I'm designing. To do this I am trying to create a custom pad in Altium that is a ring and is also plated. I've ...
0
votes
1answer
65 views

Is it a bad idea to switch from using a quartz oscillator for my timing circuit to using a MEMS oscillator? [closed]

I've read MEMS oscillators offer improved performance including phase jitter less than 500fs and frequency stability down to +-0.1ppm. It's difficult to switch from quartz because it simply works and ...
0
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0answers
32 views

Guidelines for creating through hole component PCB library

I'm working on creating a library for a MOV. Should I just put 2 through hole pads that are the pin spacing apart (7.5mm) with a slightly oversized hole compared to the pin (0.8mm oversized to 1mm)? ...
4
votes
1answer
71 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
77 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 ...
3
votes
6answers
657 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
43 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
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0answers
107 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
68 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
53 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
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0answers
54 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
78 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
72 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
78 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
88 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
78 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
60 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
53 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
736 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
349 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
58 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
110 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
60 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
72 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
94 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
110 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?