New answers tagged pcb
2
votes
Do I need to add capacitors at each VDD VSS port of a MCU chip?
Yes.
Don't try to outguess the chip designers. Follow what's in the datasheet exactly.
I saw one case where an engineer tried to save $0.05 by leaving one capacitor off. The design was in production, ...
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0
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Do I need to add capacitors at each VDD VSS port of a MCU chip?
Yes, for best results, the datasheet mandates to have bypass caps of suggested values on all supply pins. Read the datasheet for details, along with the hardware design appnotes, and a practical ...
- 172k
5
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Do I need to add capacitors at each VDD VSS port of a MCU chip?
The Getting started with STM32F10xxx hardware development application note says:
2.2 Power supply schemes
The VDD pins must be connected to VDD with external decoupling capacitors (one 100 nF ...
- 20.1k
0
votes
MP2315s buck converter not working
From the first look of your schematic and datasheet, I think you configured AAM wrong by connecting to GND. The datasheet mentioned either leave the pin floating, connect to VCC or connect to a ...
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0
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Do I need resistors in my circuit?
I haven't time to dig into this for you, but there's a link on page 104 of the datasheet to their paper on thermal management and this may be beneficial.
Figure 1. This picture from PCB Elec shows ...
- 180k
2
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What value should I use for the Impedance trace to copper?
The trace-to-copper distance isn't critical here. If you reduce it, then the required trace width will be slightly reduced. Which is probably not desirable because narrower traces are harder to keep ...
- 134k
0
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Altium layer stack manager problem (change thickness, save it but after I close and open Altium again it doesn't change)
To resolve this issue:
First, restart Altium as an administrator.
Then, open the project file directory (right-click the PCB file → Explore).
Next, delete the file with the ".PrjPcbStructure&...
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1
vote
Custom ESP32-S3 board usb disconnect and reconnect every second
Your battery charger is pulling 1A without asking the PC if that's OK.
USB ports are not allowed to pull 1A.
The max current that can be negotiated is only 500mA.
And you can't pull 500mA without ...
- 172k
1
vote
Gas water heater: power connection to a thermostat
That needs a card edge plug. Specifically, a RAST 2.5 plug with a 5 mm pitch (my site). You can buy RAST 2.5 plugs with 4 circuits and a 5 mm pitch here: https://www.digikey.com/en/products/detail/te-...
- 25.5k
0
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PCB routing: how to connect the ground?
Topologically all you have to do is run a trace below pin 4 of the transformer and to each pin the rat’s nest indicates- you don’t need the second layer at all. The spacing and trace width will be no ...
0
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Full Bridge Rectifier - Output Voltage Saturation
Use a battery powered oscilloscope as the one of the easiest ways to "float" the oscilloscope. Or use a transformer as the source for the rectifier.
You are fortunate that you used a signal ...
2
votes
Accepted
Full Bridge Rectifier - Output Voltage Saturation
Yes like I suspected, the diodes are in wrong polarity.
The electrolytic capacitors do not handle negative polarity well and will leak current, sometimes very heavily, in reverse direction.
The 50 ohm ...
- 172k
2
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Full Bridge Rectifier - Output Voltage Saturation
Can you please elaborate on the "short out one diode"
If the scope and signal generator share a ground, this happens even if you don't measure input and output at the same time:
All ...
- 9,638
0
votes
Accepted
Simplest way to design a PCB to mass program 10 ESP32's over a single high-speed USB-C port
You cannot connect more than one chip to USB. So you cannot put 10 CP2102 pins in parallel to one USB port.
You need a hub. Or rather, multiple hub ICs as likely you cannot find a 10-port USB hub IC.
...
- 172k
0
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Doubts about the format of 4-layer PCB
Neither of the two boards has a solid, unbroken GND plane. This is a strong indication that someone did not know what they were doing.
Broken GND planes do not necessarily lead to issues (signal ...
- 3,456
2
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Accepted
Doubts about the format of 4-layer PCB
Use power tracks rather than power plane, use signal and 3.3V tracks on the same plane and use a solid ground beneath them on the second layer. I am suggesting two different 4-layer stack-ups you can ...
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1
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Doubts about the format of 4-layer PCB
As you have 4 layers to play with, and have already afforded the luxury of power planes, I would strongly recommend that you dedicate one layer to an unbroken ground. No tracks through it at all. It ...
- 174k
1
vote
Accepted
Meander antenna in the corner of PCB
Well, several things:
Standard disclaimers apply. We don't know what you're working with, and the whole scope of RF and EMC topics is vastly wider than the one narrow little thing you may be working ...
- 45.6k
1
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Best way to design a PCB for frequent component switching?
Nothing beats 0.1" headers for practicality.
It is possible to solder 0805, 1206 or MELF components on the pins of a 0.1" header. The dimensions fit just right. You can solder a range of ...
- 81.6k
2
votes
Accepted
Are the 2 power sources connected inside this IC?
A multiplexer selects exactly one of the sources.
And even if both sources were enabled, the current limit and reverse current protection would prevent the large capacitor from having a noticeable ...
- 20.1k
0
votes
How to match 50 ohm impedance on 2 layer PCB?
On FR4, you need a width of roughly 2*t for a 50 Ω microstrip trace over a dielectric thickness of t. This is consistent with the 2.7 mm figure for t=1.5 mm. 'Two times thickness' is a good figure to ...
- 174k
1
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Is this a good design for having 2 power inputs for a PCB?
Yes the datasheet explicitly warns about spikes when hotplugging like USB. Even one meter and shorter cables have inductance. It is best to put protection than to damage the device.
There is no ...
- 172k
0
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GerbV (Gerber Viewer): How to do PNG export of only area within board outline?
try this open source online tool Gerber2Png will help you to convert to the png files you may need. it have some issues though but it works well
0
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Low Profile PCB Connector Identification
They're called board-to-board connectors. Here are some examples:
https://www.lcsc.com/products/Board-to-Board-and-Backplane-Connector_960.html
1
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Best way to design a PCB for frequent component switching?
While not a direct answer to OP's question about the best way to make it easier to replace a component multiple times, this answer provides a means to obviate that need.
Our power supply design team ...
- 11.1k
4
votes
Best way to design a PCB for frequent component switching?
If you asked me to do it, I’d do it a bit differently. First, the opamp-based circuit would be replaced by an MCU or FPGA with ADC on the input side and a DAC on the output. The initial setup would be ...
12
votes
Best way to design a PCB for frequent component switching?
Nothing directly to do with design, but specify a superior PCB laminate (typically high-Tg) and invest in good soldering tools, including a tweezer type de-soldering tool if you feel flush.
Avoid lead-...
8
votes
Best way to design a PCB for frequent component switching?
For your prototype you can use a machined-contact DIP socket and 'fly-wire' it to your board to bring the components out.
This type of socket will accept 1/8W resistors and caps with 0.300" lead ...
- 58.2k
1
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Best way to design a PCB for frequent component switching?
You can allow multiple parallel pads to add SMD and not have to
change them often unless you overshot the target.
You can have jumper traces that may be cut to increase R.
I'm guessing you should ...
- 148k
5
votes
Best way to design a PCB for frequent component switching?
If you can afford a prototype board that is different from production, just stick a pot on there, like Sandro said. Once you have it right, measure it, and put a fixed resistor in that place for ...
- 5,806
6
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Best way to design a PCB for frequent component switching?
The traditional way was to use DIP headers holding the components and a DIP socket on the PCB.
Nowadays, there are much smaller board-to-board connectors that could be used to implement the same ...
- 178k
5
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Best way to design a PCB for frequent component switching?
If the frequencies in question is low, you can use a regular 2.54 mm pin header (female) and push the legs of THT resistors and capacitors in them.
- 16.8k
8
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Best way to design a PCB for frequent component switching?
If you have enough space, just use 3 potentiometers (or other variable resistances) : one 100k max, one 1M max, one 10M max in "parallel", with a jumper to select which potentimeter to use.
...
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4
votes
LM386 Amplifier Circuit does not produce sound
R5 seems misplaced. With 1 kΩ in series with your amplifier, you are limited to a few mA of consumption, which is about what it takes in standby.
Move R5 away from your Vcc input to only be in series ...
- 16.8k
1
vote
Accepted
Is this a good design for connecting 2 power sources to the PCB?
VBUS Capacitance Compliance
You can effectively consider VBUS to be an open circuit w.r.t. +5V as VBUS will never exceed +5V by VD5_fwd + VD4_rev = 30.68V.
Reverse Current from Diodes
As per the ...
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0
votes
Is this a good schematic and did I choose the correct components?
With regard to the EP, the datasheet uses a different name:
The DAP (exposed pad) on the bottom of the WSON package is connected
to the die substrate with a conductive die attach adhesive. The DAP
...
1
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Understand nominal current of Phoenix Contact PCB headers
It's per-contact, subject to the derating curves (as mentioned in the first paragraph). There will be some heating between adjacent pins at high current and so there is a particular chart for this on ...
- 180k
0
votes
Is this a good schematic and did I choose the correct components?
There shouldn't be any issues using a resistor here, but if you aren't using the enable function, I would just tie it directly. One less component on your BOM. My best guess for why there's a resistor ...
- 38.5k
3
votes
Can I trust Altium Designer Impedance Calculator over my PCB Fab?
In my experience, no two or more different fabricators will give he same geometries for a given controlled impedance.
They may have the same overall envelope (track + gap + track) for a differential ...
- 22.6k
1
vote
Best location for a heat sink - On top of SMD package IC or bottom of PCB
The common way is to use a heatsink with thermal gap fill pad on the top or bottom.
If you have varying package heights on the top obtaining a suitable thermal gap filler might be difficult, so the ...
- 24k
0
votes
Why this PMIC has Via between capacitor and PMIC pins?
The design likely has a plane for that signal/power rail, which also acts as a capacitor with the ground plane. Therefore it's a good practice to connect the pin to the plane as close to the pin as ...
- 3,704
0
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Difference between clamp and clip circuit
There seems to be a confusion in the question. It is comparing two different types of diode circuits: a simple DC clipper and a more complex AC+DC clamper. Let's break them down.
Clipper circuit
Basic ...
- 19.4k
2
votes
Need for cleaning solder residue for 7mm spacing due to breakdown voltage
You could have specified that the boards should be cleaned for a nominal cost adder.
All types of soldering leave flux residue. Wave soldering more so since the flux has to be spread over the entire ...
0
votes
Is there a way to search like CTRL+F in Gerbers or a PCB picture to find a specific part?
I've tried OCR on a PDF editor program on old assembly documents and it couldn't recognize text that was rotated or tiny. Perhaps the boxes surrounding the text caused problems.
If you use ODB++ PCB ...
- 11.2k
2
votes
Do I have to bother with isolation?
If you look at a desktop PC from a few years ago - the sort that came with RS232 ports as standard - then they made no attempt to isolate the RS232 outputs.
The 9 or 25 way D-type connector would have ...
- 20k
2
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Do I have to bother with isolation?
Typically no, like you said RS232 distances are short. I have isolated RS232 but for a different reason, I had a sensitive analog board and I wanted to avoid any kind of ground loop.
So if you need to ...
- 88.8k
1
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Is there a way to search like CTRL+F in Gerbers or a PCB picture to find a specific part?
I would say it's not ready yet. I gave ChatGPT-4o an image of the silk-screen layer of a non-trivial PCB design (more than 100 components, with logos and such like), and a .csv list of designators and ...
1
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Is there a way to search like CTRL+F in Gerbers or a PCB picture to find a specific part?
No OCR is required.
If you've already got x-y location and the name of the part in a text file, what exactly are you after?
Consider using a ready-made tool to make images (say PNGs) of the Gerber ...
- 16.2k
2
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Is there a way to search like CTRL+F in Gerbers or a PCB picture to find a specific part?
No. Neither Gerbers nor pictures contain that data.
Pick and place data usually only contains "position" "part (model) number", not "designator" (like "U17") to ...
- 100k
2
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Do I have to bother with isolation?
If all your devices are hard-wired to the same supply ground, then isolation is almost certainly not necessary.
If all your devices plug into the same ground, then isolation is probably not necessary, ...
- 174k
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