Questions tagged [pcb]
PCB is the acronym to Printed Circuit Board. A PCB is a carrier for the circuit's components and their electrical connections.
789
questions with no upvoted or accepted answers
10
votes
0
answers
178
views
Which stackup to choose for JLPCB FR4 up to ~10GHz
I am aware that 10GHz on FR4 is not ideal, but this is an hobby project and I can tolerate some losses. The 10GHz on the PCB is minimal (probably only a short coplanar waveguide or microstrip with 2 ...
- 211
5
votes
0
answers
827
views
Custom RP2040 PCB Not Detected by PC
I designed a custom RP2040 to control some 24V LED strips. The official hardware design guide from the Raspberry Pi Foundation is what I followed for my design. It was then sent out to JLCPCB for the ...
- 475
5
votes
0
answers
214
views
Invisible magic components that spoil the Eagle preview
You know, after the eagle board design is finished, you can see the card on the preview screen.
I'll show you two examples. There is no problem with one. The card is centered on the preview screen.
...
- 93
4
votes
0
answers
39
views
Attempting to patch the "G75 Bug" on a Gerber Level
Context
I am currently looking for alternative PCB manufacturers for my company and have sent Gerber files to some (Chinese) companies.
These Gerber files have already been used in the past by various ...
- 2,713
4
votes
0
answers
2k
views
Capacitive touch sensor design
I made a PCB with several capacitive pads to be read by IQS127.
They work, but any material I put close to the PCB surface will trigger the output, even the 8 mm glass I'm going to use.
The pads ...
- 1,179
4
votes
0
answers
120
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 ...
- 357
4
votes
0
answers
1k
views
Qi Receiver on PCB
I'm looking at implementing Qi charging in my project, would it be possible to have a Qi receiver directly on the back of the PCB (copper traces in the shape of a coil)? Could this interfere with the ...
- 49
3
votes
0
answers
41
views
How to verify if SDRAM alternative is a direct drop in replacement?
I'm trying to verify whether the two SDRAM chips are complete drop in replacements of each other. I've verified the footprint, electrical characteristics and various timing parameters (namely CL, tRCD,...
- 51
3
votes
0
answers
213
views
How to find rise/fall time of SPI?
I want to calculate the frequency of the SPI2 line of the STM32L073 chip. I downloaded the STM32L073 ISB file. I followed these steps while doing the calculations.
For example I wanted to look at the ...
- 653
3
votes
0
answers
186
views
DDR Trace Length in Motherboards
I was trying to understand DDR, Trace-length, and signal integrity.
Most of the datasheets, For example, iMX8M Mini (Doc: IMX8MMHDG) clearly specifies what are the requirements for the each signal in ...
3
votes
0
answers
80
views
How to handle deleted components in PCB layout
I am trying to "update" an Altium project; deleting 3 sheets with all components and adding 2 sheets. I completed the schematics and next step is layout.
As I deleted components, I saw so ...
- 61
3
votes
0
answers
309
views
Esp32 rf design review
Preamble: this is the first time I'm working in rf circuit design, I went simple and I hope I didn't make any silly mistakes, but I still have some doubts.
I am currently designing a garden programmer ...
- 185
3
votes
0
answers
57
views
Does through-hole mounting have an advantage over surface mounting in sub-zero temperatures?
I am working on a device that I want to work outdoors far up north (e.g. on a farm), maybe down to -40C. I read a lot about through-hole circuit boards being more resistant to environmental stress ...
- 562
3
votes
0
answers
319
views
Enclosure/boxes for high voltage PCB
It is time to choose the proper enclosure for a high voltage PCB. We will need to do holes for LV external connectors and external connectors for high voltage wires. I was looking for standard boxes ...
- 787
3
votes
0
answers
533
views
When is a 5mm thick PCB a better choice than solid bus bars?
I have in my possession a 5mm thick printed circuit board. It comes from a 2000-era Sun Blade server, where it connected 4 redundant 70A power supplies.
I also have a need to assemble some high ...
- 261
3
votes
0
answers
315
views
How to distribuite high current in multilayer PCBs
I'm designing a 150Amp controlled rectifier and I'd like to know how to distribute the current using a multilayer design.
Currently, I have a 4 layer design containing:
Top Layer: 6oz, Vdc+ and Vdc-...
- 31
3
votes
3
answers
437
views
Timing a circuit's 'on-cycle' after a push button switch is pressed
First off, thank you for reading all of this - you are the part of the internet that gives me hope for mankind. I’m looking for a circuit that I would think is relatively straightforward, but has a ...
- 31
3
votes
0
answers
128
views
silkscreen artifacts on pcb
I often see silkscreen prints between pads on pcbs. Especially I noticed this on "high voltage" designs (SMPS). What is the reason for that? Maybe it is to
improve automatic inspection
prevent for ...
- 31
3
votes
1
answer
2k
views
Balun single-ended 50 Ω to LVDS 100 Ω conversion
I have an LVDS differential 100 Ω signal which I want to convert to a single-ended 50 Ω signal. I want to use a BALUN for this conversion.
What kind of BALUN should I use here?
Some BALUNs have a 1:1 ...
- 149
3
votes
0
answers
2k
views
STM32F429ZIT6 with SDRAM IS42S16320F Read/Write Issue
I designed a board which is containing two SDRAM (IS42S16320F) and STM32F476ZIT6 MCU (and other components also). I can access the SDRAM but the data is changing independently from the code. My board ...
3
votes
0
answers
834
views
PCB trace caps (a.k.a. finger / interdigital caps) formula
I am trying to calculate a two-fingered, both on the same layer, capacitor. I have run into a few papers on it but they are taking a ground plane on the other side of the PCB into consideration and ...
- 1,060
3
votes
0
answers
314
views
Formulas for Integral Components
Formulas for Integral Components:
I am looking for "simple" approximative formulas for integral components. In particular for:
A grounded interdigital capacitor (i.e. above a ground plane and with ...
- 5,189
3
votes
1
answer
1k
views
Limit KiCAD track selection to current layer
When I do the track selection in KiCAD and click Select -> Connected Tracks it also selects tracks connected through vias on the back of the board.
I only want ...
- 247
3
votes
1
answer
213
views
What is this breadboard that can be soldered on a PCB
Very simple question. What is the part number of this small bread board on this board.
There are two breadboards on it. The smaller one actually is soldered on the PCB and it is connected to IOs of ...
- 117
2
votes
1
answer
89
views
Do you put a ferrite bead on both the positive voltage and GND trace?
I'm designing some basic DC power filtering for a very simple PCB. Do ferrite beads go on BOTH the positive voltage trace AND the GND trace, or should GND be completely free?
- 253
2
votes
0
answers
30
views
What are the common package names for pin spacing in multiples near 50-mils?
I'm looking for component package names that are known to provide conductors on (nearly) 50-mil spacing so it fits well on a 50x50mil SMT protyping board.
I know SOIC are 50-mil, and even SOT-223 is ...
- 1,786
2
votes
0
answers
45
views
Can 5mm UV LEDs cure solder mask?
Is it possible to cure solder mask using about 32 5mm UV LEDs spread evenly above a PCB (10x15 cm). If yes, since they are weak, what would the cure time be?
I want to make my own PCB mill and I want ...
- 41
2
votes
1
answer
130
views
How should the gas discharge tubes for RS-422/RS-485 be placed and routing on the PCB?
I adjusted the gas discharge tubes to be close to the connectors on the PCB. The RS-422 lines have a differential line impedance of 100 Ω. My concern is, aren't the lines between the connector and the ...
- 543
2
votes
0
answers
106
views
Adding a Chassis Ground at the Midpoint of a PCB
The PCB I designed is 6-layer. I will create a chassis ground in the form of a frame surrounding the mounting holes and add a Y capacitor between and to the signal GND. And I will surround this ...
- 543
2
votes
0
answers
65
views
Power supply circuit explanation/conjectures
I have a small label-maker; it runs off 8 AA batteries (i.e., about 12V) or (supposedly) a 9.5VDC power brick with a tubular connector with + on the outside.
It won't work with just the power brick, ...
- 249
2
votes
1
answer
79
views
Ways to Change IPC 4761 Via Type in Altium Designer
I would like to change the via type in Altium Designer in the IPC 4761 section. However, Altium Designer is not allowing me to change it. Is there any way to change it?
Moreover, if I would like to ...
- 31
2
votes
0
answers
117
views
Why were these mods done?
I have a "Quantum Data 882E-HDMI Video Generator" in for repair. It has a fault or two, but also has number of mods which I would help with.
Questions regarding board "84-00221 Rev B/99-...
- 33
2
votes
1
answer
108
views
Do I need decoupling capacitors in this schematic?
I just read about 'decoupling capacitors' to stabilize the voltage. I have some small voltage drops on this schematic when I made it into a PCB.
Can capacitors would solve the problem?
If yes, where ...
- 89
2
votes
1
answer
187
views
Should I separate power ground from control ground?
I am designing the single phase inverter. The input of the inverter is around 35 Vdc, and output is 24 Vac. The output currents will be below 1A. I control the inverter with F280039C from TI on a ...
2
votes
0
answers
129
views
How to fully connect component pad with the ground plane
I'm trying to make a simple PCB board on eagle.
I've learned how to make a ground plane, and it worked great. But I wonder, why is the component pins/pads connected to ground as more like a plus (+) ...
- 33
2
votes
1
answer
82
views
Best ways to mask missing toner after toner transfer PCB etching
I want to make a general guide for masking the missing toner on copper clad after toner transfer.
The masking methods I know so far:
Permanent marker (some say it doesn't work, I am intimidated by it ...
- 539
2
votes
0
answers
188
views
White residue on circuit board
What is this white powder on my induction cooker hob? Is is metal salt? The capacitor recently melted
- 21
2
votes
1
answer
2k
views
ESP32 not able to detect any I2C devices
I am trying my hand at building a smart watch from scratch. I just got the latest PCBs delivered and upon soldering everything I found that the TTGO micro-32, essentially an ESP32, cannot detect any ...
2
votes
0
answers
63
views
Connector identification for Avermedia C875
I have an AverMedia C875 device, I would like to capture an analog output of my VCR with it. The device has a specific connector for such purposes, but I sadly don't have the dongle that originally ...
- 21
2
votes
0
answers
213
views
Moving BGA pads 0.01mm and making them smaller to work with JLCPCB capabilities
JLCPCB has requirements that mean some BGA packages can't be used because of minimum via size and minimum track spacing and sizes of pads to vis etc.
To overcome this I came up with an idea that in ...
- 21
2
votes
0
answers
95
views
Blocking BLE Chip Antenna from picking up signals in one direction
I am designing a BLE scanner/observer which uses a ceramic antenna.
I was wondering if there is any way to design the PCB such that the antenna chip only picks up signals from in front of it instead ...
- 21
2
votes
0
answers
82
views
Circuit to Disable 24VDC to Load via +24VDC Logic Output
I have a load that is powered by a +24VDC source. The load can draw a max of 400mA. I would like a simple and effective circuit to disable power when a 0-24VDC logic signal is high; in addition, I ...
- 21
2
votes
0
answers
56
views
How to show only specific net in Diptrace?
How to show only specific net in Diptrace?
Let's say i have a big board and i want to trace all the power traces first, i'd like to hide all other nets ratlines so it's easier to see just the power ...
2
votes
0
answers
164
views
Will my design work to program an ESP8285 IC?
Will this design work to program an ESP8285?
I was trying to design an ESP8285 development board for the first time.
Before sending the design to manufacturing I would like to know whether or not the ...
2
votes
0
answers
93
views
RF PCB Layout for 915Mhz + BLE: Which is better?
I am designing a small board with a 915Mhz transceiver IC breakout (based on the CC1101 + CC1190 chipsets), controlled by an STM32. I have used the popular nrf24l01 chipset in the past, but was ...
- 2,191
2
votes
0
answers
146
views
oscillators tolerance to ultrasonic cleaning
I use clock oscillators like ACHL-10.000MHZ in pretty much any board that contains a micro-controller. Recently, I've started using MEMS clock oscillators like AMPMAFB-33.0000T for their claimed ...
- 437
2
votes
1
answer
101
views
What is the name of these connectors? (XBee Radio Module)
I'm migrating a design from an older through hole module, to a new module that has edge connectors. The dev kit has these nice spring loaded connectors on the carrier board where the module just pops ...
2
votes
0
answers
53
views
Understand how to integrate STM32F407VG MCU on custom PCB and program it
I have been messing around with the STMF407VG for a few weeks now using a discovery board. Been the steep learning curve but I think I have made significant progress on learning firmware development ...
- 183
2
votes
0
answers
84
views
What tools can I use for PCB making at home?
I want to create my own PCBs for prototyping and hobby purposes. I have experimented with buying them in China, which is cheap but not very fast. No idea on the quality either, but for $5 for 5 boards,...
- 213
2
votes
1
answer
104
views
Capacitive Touch Pad Design with TTP224 ic
I am designing circular capacitive touch pads of Dia:20mm driving from TTP224 IC on my PCB. There will be 2mm glass panel above Touch pads. My PCB contains other circuits like Arduino, Antenna bands ...
