hybridfree/eevblog-posts huggingface dataset:
UPS won't switch to battery power with second PC. - Page 1
Forum section: electronics / projects

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: March 22, 2018, 11:21:32 pm
content: I have two PC's connected to a UPS that I use for mining and they run 24/7.Problem is one of them is causing me problems. It's not an overload issue seems like something might be up with the PSU since it works fine with the other PC with a 600W heater connected to it.Could the PSU be behaving strangely for example causing some kind of power surge back to the UPS when the power cuts out and the UPS protects itself by shutting down instead of switching to battery power?Could it possibly be the GPU since it doesnt behave this way when I am doing a CPU stress test?I could go trough the process of elimination but it's taken me a long time to isolate other variables and narrow it down to something with this specific PC.Any ideas are welcome.

author: BradC
author_rank: Super Contributor
timestamp: March 23, 2018, 12:05:29 am
content: Which UPS? A modified sine wave unit will often cause issues with active PFC power supplies leading to one, the other or both hitting some form of protective shutdown. These issues don't occur with genuine sine wave units.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: March 23, 2018, 12:26:34 am
content: Quote from: BradC on March 23, 2018, 12:05:29 amI'm talking about a CyberPower cps1000e.It outputs a pure sinewave up to 40% load and then turns into a modified sinewave.That being said however, it can't be an issue of non sinusoidal power since even when powered alone (30% load) it still wont let the UPS transfer to battery mode...
UPS/lead-acid battery, 12v/5A: looking for a good and educational schematic - Page 1
Forum section: electronics / projects

author: 0db
author_rank: Frequent Contributor
timestamp: February 26, 2020, 04:15:33 pm
content: hiI'd like to build an Uninterruptible Power Supply for an SBC engine operating at 12V.The engine needs 5A, and I'd like to use a common lead-acid battery.I have Googled, but I have only found confusing schematics, and I'd like to see something educational with a pretty description.Thanks

author: rvalente
author_rank: Frequent Contributor
timestamp: February 26, 2020, 05:36:24 pm
content: What is a SBC engine? Single cylinder?This may help you:http://ww1.microchip.com/downloads/en/appnotes/01015a.pdf

author: 0db
author_rank: Frequent Contributor
timestamp: February 26, 2020, 05:59:06 pm
content: Quote from: rvalente on February 26, 2020, 05:36:24 pmSBC = single board computer. It's a x86-compatible computer on a single board, it has a video graphic unit and hard drive and it eats 4 Ampere. The UPS is required to let the computer to shutdown correctly the hard drive without damaging the filesystem.Thanks for the link
uRuler Gerbers - Page 1
Forum section: electronics / projects

author: EEVblog
author_rank: Unknown
timestamp: September 17, 2012, 01:46:11 am
content: For those who have asked, here are the gerbers.http://www.eevblog.com/projects/uruler/Dave.

author: andyturk
author_rank: Frequent Contributor
timestamp: September 17, 2012, 05:53:31 am
content: Very cool. Thanks!But using a proprietary file format (.rar) for open source project files? Hmmm.

author: EEVblog
author_rank: Unknown
timestamp: September 17, 2012, 06:04:16 am
content: Quote from: andyturk on September 17, 2012, 05:53:31 amHadn't given it a thought.What should I be using? (Windoze)Dave.

author: cwalex
author_rank: Frequent Contributor
timestamp: September 17, 2012, 06:24:01 am
content: Quote from: andyturk on September 17, 2012, 05:53:31 amYou can use 7zip for rar. It's open source, has windows and linux support.Are you planning on selling these Dave? I'd like to buy one, looks awesome.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 17, 2012, 08:19:45 am
content: One minor omission - mil eqiuvalents of the 0.1mm increments of drill sizes - don't know how common it is but PCAD shows drill sizes in mils if in imperial mode...and if you want a real luxury (expensive) version, on the other side have a matrix of all the different resist and silkscreen colours.QuoteZip is much more commonly used, and supported directly by more recent Windoze versions, and universally accepted by PCB manufacturers.I don't give a crap about proprietoriness, just ease of use and ubiquity.

author: Psi
author_rank: Super Contributor
timestamp: September 17, 2012, 09:04:17 am
content: I really like those holes on the ends, makes finding the right size hole for any TH component really easy.

author: samgab
author_rank: Frequent Contributor
timestamp: September 17, 2012, 09:25:28 am
content: These are so freakin' cool. Cheers for this Dave. Now, how to get some made in NZ...

author: Psi
author_rank: Super Contributor
timestamp: September 17, 2012, 11:43:19 am
content: Quote from: samgab on September 17, 2012, 09:25:28 amDave's ones were made in NZ, at pcbzone in Auckland

author: EEVblog
author_rank: Unknown
timestamp: September 17, 2012, 11:44:38 am
content: Quote from: mikeselectricstuff on September 17, 2012, 08:19:45 amYeah, had to leave something out in the end. Only had a mil->mm table.Drill sizes are mostly done in mm anyway.QuoteThat would be nice. These were unfortunately a last minute rush job. Circuit Labs only had time to do a single sided run, and no gold plate, so it's only bare copper. Ideally I wanted metric one side, imperial the other etc.The bigger wider 30cm rulers fit a lot more info and clearer text, but I liked the idea of compact 6" rule. Wider than a standard 6" rule though, so expanded to 7"Should be very durable using Circuit Labs photo emulsion component overlay technique.Dave.

author: T4P
author_rank: Super Contributor
timestamp: September 17, 2012, 01:22:39 pm
content: Thanks Dave! I'm gonna order a few from seeedstudio
US 120V Hard Wired Surge Suppressor? - Page 1
Forum section: electronics / projects

author: sacherjj
author_rank: Frequent Contributor
timestamp: February 28, 2012, 03:05:58 pm
content: I'm building a new electronics bench in an 8x8 feet area, that currently has two outlets. I'm pulling one outlet and replacing it with a blank cover, 90 degree into armored cable up to my bench. This will go to a dual switch. One switch will turn on the overheat light and the other will power my bench outlet lines. I'm using 1 - 5' 10 outlet plug mold strips on each side of my L shaped bench. I have a separate 15 A feed to this location, so I don't expect loading issues. My electronics bench will be pretty low power.With this setup, I will have a way to hit both switches down and assure that I'm completely dead to the bench, so I didn't have to worry about forgetting my soldering iron, etc. While I don't expect to be in a situation requiring an emergency kill, it will allow that as well.Does anyone have a recommendation for a module I can put in this setup to have wired in surge/transient suppression? I'm finding things like this:http://www.amazon.com/Ditek-120HW-Parallel-Power-Protector/dp/B001UKKSV0But I wanted to get advice if anyone has practical experience with putting one of these in.

author: saturation
author_rank: Super Contributor
timestamp: February 28, 2012, 04:01:59 pm
content: Just some thoughts. Surge suppressors, even the whole line or whole home variants, are like fuses and not resettable. If they are faced with small surges over time, eventually they will fail, so its best to be able to replace them easily and quickly, as plug in modules rather than hard wired; alas such types are far more expensive than simple plug-in-the-wall types simply because plug-in-the-wall types are more in demand, and offer the same level of protection. Thus, its not practical to have a branch circuit SPD albeit its offered for sale [not to mention the installation costs]. For total protection, a distribution box SPD is a better option for taking transients from the grid [ if its modular], but in-home generated transients or those coupled to the home wiring by lightning or similar events, the last level of protection is still the wall plug in protector to which your devices are plugged into.The above is an example of a modular distribution box SPD with easily replaced modules; each module can protect a branch circuit or a whole floor, say in a building.

author: T4P
author_rank: Super Contributor
timestamp: February 28, 2012, 06:13:11 pm
content: Using DIN rail-sized ELCB's can be expensive , but hell they last a long time .

author: sacherjj
author_rank: Frequent Contributor
timestamp: February 28, 2012, 06:42:49 pm
content: Quote from: Dave.S on February 28, 2012, 06:13:11 pmThat is what I'm seeing in searching. The expense part...
US Galden HT230 sourcing for vapor soldering - Page 1
Forum section: electronics / projects

author: vfeev
author_rank: Newbie
timestamp: February 23, 2021, 12:35:21 am
content: Hello,I want to give vapor soldering a try and it seems the highest cost is sourcing Galden. Since I'm very unsure about the results, I would like to minimize the costs.I contacted Synquest and Inland Vacuum and got about $350 for 1kg of product (ordering less would not reduce the price significantly).Questions:Any other suppliers in the US I should check?Any good/bad experiences using a particular US supplier?Since a typical usage seem to be below 0.5 kg, does anyone in the US (or even better, SF Bay Area) wants to split the order? Or alternatively sell their leftover Galden? PM me.
US-Made PSU for rail application - Page 1
Forum section: electronics / projects

author: 741
author_rank: Frequent Contributor
timestamp: March 21, 2025, 10:36:24 am
content: We have a railway/railroad product that was going to use a Melcher S Series PSU unit.This has fallen foul of BABA (Build America Buy America), depite the fact Melcher is part of Bel-Fuse.Can anyone suggest a US-made product line that is similar, or likely manufacturers?

author: moffy
author_rank: Super Contributor
timestamp: March 21, 2025, 11:18:59 am
content: A search for American made PSUs:https://www.google.com/search?client=opera&q=american+made+psu&sourceid=opera&ie=UTF-8&oe=UTF-8

author: mtwieg
author_rank: Frequent Contributor
timestamp: March 22, 2025, 12:37:37 pm
content: What specific certifications do you require for railway applications?
US Replacement for UMCCC 400 C Core - Page 1
Forum section: electronics / projects

author: LaserSteve
author_rank: Super Contributor
timestamp: August 01, 2019, 08:07:18 am
content: I need to duplicate a high voltage power supply in an academic paper. Rectified and filtered 220 line is stepped up by a ~ 1:140 transformer based on four UMCCC 400 "C" cores. In the schematic its driven by a FET Half Bridge with a one and a half turn copper tape primary and 140 turns of silicone wire for the primary. A series resistor of a few Ohms is frequency range is 2 to 40 KHz adjusted for peak power transfer to a mostly capacitive load in short pulses.Application is driving an Atmospheric Pressure Dielectric Barrier Discharge in a research lab at work. I need something similar to UMCCC 400 readily available in the US.DBDs in this case are a Townsend discharge for ignition that transition to arrays of parallel streamers. The load is a large diameter quartz plasma tube filled with methane, a trace of argon or helium to aid in ignition, and a catalyst on ceramic spheres to aid in the formation of a chemical compound.. The pulses are capacitive coupled to the load via a simple inductive match. Downstream is a GC/MS looking for the desired compound to see how well the developmental catalyst works. The quartz tube forms the capacitor, and a rod in the center of the catalyst is the inner electrode. So all the pulse energy passes through the quartz or fused silica.I'm well familiar with the needed safety precautions. I've worked with plasmas for years. This is usual procedure in a university lab, "Here, Build This!", usually an poorly documented circuit, which almost always leads to a development project where I build "That Expensive and New Design That Actually Works"My take from the graphs is 100 to 1000 watts of average power circulating in the system.Normally I would research this myself but Mom (87) is in the hospital, she cannot speak for herself and I'm the only child. Suggestions please?Data Sheet for original cores:http://3.imimg.com/data3/NU/KA/MY-8750762/amorphous-c-cores.pdfThanks,Steve

author: Wolfram
author_rank: Frequent Contributor
timestamp: August 05, 2019, 12:43:34 pm
content: The Hitachi AMCC 400 core size seems to be the same size, from the datasheets I was able to find. These cores are available in 2605SA1 material from Dexter Magnetics in the US:https://shop.dextermag.com/product-p/amcc-400.htm
Usability of One-wire devices in a star configuration? - Page 1
Forum section: electronics / projects

author: e100
author_rank: Frequent Contributor
timestamp: June 19, 2022, 04:43:03 pm
content: As in a microcontroller in the middle and multiple 3-core cables radiating outwards to different locations 5-7 meters apart all sharing the same ground, Vcc and signal with a single pullup resistor.Has anyone found the practical limits for devices such as the DS18B20 temperature sensor?Maxim has an application notehttps://www.maximintegrated.com/en/design/technical-documents/tutorials/1/148.htmlbut I'm interested in peoples real world experiences.

author: bateau020
author_rank: Frequent Contributor
timestamp: June 20, 2022, 12:14:04 pm
content: Running a moderately large 1-wire network since more than 15 years, so maybe I can help.Avoid a star topology, especially when you use different device types (you might not do now, but you will be tempted to do so!). When you put a scope on it you'll be surprised of the bad signal integrity when using such long lines. Not only impedance mismatch, but also the always imperfect cable shielding will mess with the signal, and noise suppression is hard because the 1-wire bus is no differential bus.What I do:* use a switched network, with a good bus master. Not a CPU pin with a pull-up resistor. Use hard (active) pull-up. Chain the devices on each switch leg.* keep the distance from the chaining point to the device very short, and add a ferrite bead going into the device (although not all devices like that).* I prefer parasitic devices, (or make them parasitic with a cap and a BAT54S) as that way you get something like a differential load. And when a device needs more power than possible over the line, I add local independent power.* sample 1 DS18B20 at a time. Do not sample in parallel, as the sampling will generate noise on the line. Yes, that is 1 sec per temperature sample, but so be it.* use CRC checks and retries in your code. You will get a couple of CRC fails from time to time.* add ESD protection.
Usage of OpAmp Integrator for measuring thermocouple - Page 1
Forum section: electronics / projects

author: shangaoren
author_rank: Regular Contributor
timestamp: August 29, 2023, 09:10:04 pm
content: I saw this project and i can't understand how this could work with the OpAmp integrator design to measure the thermocouple output of the tip :https://github.com/Jana-Marie/Otter-Iron-PRO/blob/master/v2.0/Bottom/OtterIron_PRO_Bot.pdfI understand that the integrator can provide more accurate measure for thermocouple that have a low voltage and maybe some noise in this application but how this one is going to reset after some time, i mean it could not integrate for an infinite time or am i missing something ?

author: TimFox
author_rank: Super Contributor
timestamp: August 29, 2023, 09:25:58 pm
content: Do you mean U5?It's not an integrator; it is a high-gain DC amplifier with a capacitor in the feedback loop to control high-frequency response.

author: shangaoren
author_rank: Regular Contributor
timestamp: August 30, 2023, 06:45:06 am
content: Oh, i see, i'm not very familiar with OpAmp circuitsSo here the capacitor is too small to create an Integrator ? And by control do you mean that C16 act with R16 to create a high pass filter or this is something else ?

author: Kleinstein
author_rank: Super Contributor
timestamp: August 30, 2023, 06:53:30 am
content: C16 and R15 (the one in parallel to C16) make a low pass filter function. An integrator can be seen as a low pass with 0 cross over and thus R15 as infinite resistance.In this case C16 is only 10 pF and rather small, more like helping the OP-amp with loop stability. Chances are it would need a larger value (e.g. more like 10 nF) to make a significant effect.

author: gnuarm
author_rank: Super Contributor
timestamp: August 30, 2023, 07:00:40 am
content: Does anyone have an idea of what R14 is for?

author: magic
author_rank: Super Contributor
timestamp: August 30, 2023, 07:19:56 am
content: At DC, C16 is open circuit and this is a noninverting amplifier with gain (R15+R16)/R16.At some MHz, 18pF has less impedance than any resistor in the circuit, and effectively delivers unity feedback to U5.At some kHz (the time constant of 750kΩ·18pF, whatever it is) C16 impedance is less than R15 but more than R16 and closed loop gain gradually falls from its DC value towards unity.The purpose is probably to reduce high frequency noise going into the ADC.

author: gnuarm
author_rank: Super Contributor
timestamp: August 30, 2023, 09:06:35 am
content: Quote from: magic on August 30, 2023, 07:19:56 amA capacitor on the non-inverting input would provide a similar filtering action, but would not have such a high stop-band floor. It would instead attenuate infinitely as the frequency rises. It is important for the operation of ADCs for the input to be band limited.I see an unused cap at C17, but it would not be working in conjunction with R17, rather some impedance of the input signal, which would be expected to be very low.
no text - Page 1
Forum section: electronics / projects

author: daywalkerdha
author_rank: Contributor
timestamp: February 13, 2013, 07:53:41 am
content: no text

author: dermitza
author_rank: Contributor
timestamp: February 13, 2013, 08:29:42 am
content: I have used quite a few FT232R chips, and they will allow you to draw 500mA without reprogramming. As i see it, this section"For USB high-power bus powered applications (one that consumes greater than 100mA, and up to 500mA of current from the USB bus), the power consumption of the application must be set in the Max Power field in the internal FT232R EEPROM. A high-power bus powered application uses the descriptor in the internal FT232R EEPROM to inform the system of its power requirements."is just for general spec conformance. I would still add the MOSFET configuration in Figure 6.3 though.

author: dermitza
author_rank: Contributor
timestamp: February 13, 2013, 09:20:07 am
content: Quote from: daywalkerdha on February 13, 2013, 08:42:34 amYou will ensure you are hardware conformant to spec by using the MOSFET for your system load. It will ensure the device does not draw more than 100mA during enumeration (only the FT232R powered), once it is enumerated it is allowed to draw up to 500mA. If you want to suspend it, the MOSFET will switch off your system and the FT232R will enter sleep mode to conform to spec.Fromhttp://www.ftdichip.com/Support/Knowledgebase/index.html?usbpoweroptions.htm"·The maximum current that can be supplied over the USB bus without violating the USB specification is 500mA. Do not enter a value of more than 500mA in the Max Bus Power field.·On plug-in, no USB product is allowed to consume more than 100mA from the USB bus until USB enumeration is complete i.e. the product and it's USB drivers are successfully loaded by the host PC. Special care has to be taken in the case of high power Bus Powered products, however the PWREN# pin of the BM series devices simplifies such designs. "Setting the EEPROM is used for allowing the driver, host OS and end-user to see the current consumption numeric value as set by you. As I understand it it does not serve any further software/hardware function (at least for the FT232R chip).And BTW, you dont need to program the EEPROM before soldering, you can do it in-system, using MProg or FT_Prog.

author: Neilm
author_rank: Super Contributor
timestamp: February 13, 2013, 07:59:09 pm
content: I have used FTDI chips in the past and it only takes a few seconds to programme in when it is on the board. What ever solution you use will have to report to the PC that it will want 500mA, so either you programme a chip (on or off board) or you find a chip that combines the lot. I have seen Li charger chips that will talk down the USB (some of TIs offering spring to mind), but I don't know how easy they are to use - the ones I have seen have been BGA packs which are not fun to use unless you are in a company.Neil

author: PA0PBZ
author_rank: Super Contributor
timestamp: February 13, 2013, 08:17:23 pm
content: Some TI ones, not BGA but MLP:http://www.ti.com/lit/ds/symlink/bq24022.pdf
USB 2.0 480mbps design opinion - Page 1
Forum section: electronics / projects

author: jealcuna
author_rank: Contributor
timestamp: June 13, 2021, 11:37:24 pm
content: Hi folks, I recently made my first usb pcb route design. I have reading the theory behind the transmission lines. So i keep my little knowledge to make possible my design. However, I would like to read the very experimented people here in this wonderful blog. Any idea/suggestion/opinion will be good received.The circuit consists in a usb multiplexer in order to use esp32-s2 otg option, or use ch340k usb-serial converter to program esp32. In order to use the high speed of esp32 otg, I match the impedance to 90ohm before and after usb mux. Also the length is matched.I attach a few capture of the design.

author: ataradov
author_rank: Super Contributor
timestamp: June 14, 2021, 12:25:22 am
content: ESP32 only has USB Full-Speed. And none of that transmission line theory really matters. Virtually any design will work.

author: jealcuna
author_rank: Contributor
timestamp: June 14, 2021, 12:32:48 am
content: Oh, you are right.However, if this was the case of a H S usb implementation, is this design correct?, I am a little suspicious about the route from the inner part of the muxer to the esp32. And also the match length arc is in the little trace.

author: ataradov
author_rank: Super Contributor
timestamp: June 14, 2021, 12:57:36 am
content: It is fine. In reality for traces that short is does not matter that much. Even if you did not match the length, it would still be well within allowed tolerances.I personally would not even worry about the trace width, just route it with the trace width the same as the IC pad width, so there is no awkward width transition.
USB 2.0 charger standard-or taking 280ma off usb bus while not in charging mode - Page 1
Forum section: electronics / projects

author: jjrosent
author_rank: Newbie
timestamp: January 17, 2012, 08:14:14 am
content: I was looking at the Arduino FIO (atmega168 running at 3.3v with LION and xbee breakouts) reference schematic and noticed whoever laid out that board hooked the usb power up to the DC port on the MAX 1555 charge chip. Presumably they did this not by accident but to charge the battery at the full 280ma instead of the usb limited 100ma. Does anyone have experience with breaking the 2007 Battery Charging Specification like this? Is it common nowadays or as you'd expect, ill advised?Thanks!FIOhttp://arduino.cc/en/Main/ArduinoBoardFioFIO schematichttp://arduino.cc/en/uploads/Main/Arduino-Fio-schematic.pdfMAX 1555 datasheethttp://datasheets.maxim-ic.com/en/ds/MAX1551-MAX1555.pdfUSB 2.0 charging on wikipediahttp://en.wikipedia.org/wiki/USB2#Charging_ports

author: mobbarley
author_rank: Regular Contributor
timestamp: January 17, 2012, 09:06:56 am
content: Although it is non compliant it's very rare that it would be a problem - Every port these days can supply the 500mA or so for a high power device and the computer won't care less if it is on.The standard says that this power level should be negotiated but in reality it is not forced. You can see this in just about every usb novelty from hand warmers to keyboard vacuum cleaners.My mac has given me power errors and disconnected things before but this was only when using devices in it's keyboard usb connectors which have very limited power. You might see more problems if it is plugged into a device with a USB port rather than a PC or charger as the device might have limited power available (~100mA) - for example the usb port on a stereo, set top box or oscilloscope etc.

author: bfritz
author_rank: Regular Contributor
timestamp: January 18, 2012, 05:16:53 pm
content: Last time I checked, I believe the iPhone, iPad, etc. Apple products will only pull the 100mA from a device until they get the reply from the host. To make this work with their chargers at currents of 500mA and higher, Apple uses a resistor divider scheme on the D+ and D- pins of the USB interface.Here's a good URL on the details of reverse engineering Apple's scheme:http://www.ladyada.net/make/mintyboost/icharge.htmlThe new version of the USB spec allows for a similar idea. I don't remember the exact current they allow, somewhere about 1.6-1.8A, but the idea they use is to connect D+ to D- with a resistor of less than 200 ohms. So, some phones/pads may require this scheme.
USB 2.0 HS - Understanding Disconnect due to Signal Quality - Page 1
Forum section: electronics / projects

author: dpai
author_rank: Newbie
timestamp: June 15, 2022, 10:19:37 am
content: Hi. I have a question about the USB 2.0 protocol.I'm trying to understand how a high-speed device gets disconnected from a host in a particular scenario. I have already been digging through the specification, but can't find any answers there.Usually, when a device gets unplugged from the host, the host-side envelope detector will recognize the differential doubling of voltage on the data line as the device-side termination on the data lines is removed. This indicates a disconnect.However, I'm investigating a scenario where a device is indicated as disconnected by the host when it remains plugged in. I have added a 5m extension between the host and the device in order to reduce the signal quality to a point that it regularly fails the eye diagram mask as defined in the specification. The disconnects I'm observing are clearly caused by this circumstance.What is unclear to me is how the host driver causes the disconnect. Clearly, the envelope detector does not cause it (I have triggered on the disconnect threshold and never got a hit). I'm therefore suspecting that it could be caused by the host SW driver, e.g. it declares the device as disconnected after a certain amount of packets cannot be deciphered anymore.1. Does anybody have some insights?2. If I don't find an answer here, which forum could I try at to get an answer at?I know this is a very specific question, but I'm looking forward to hear your inputs!

author: ataradov
author_rank: Super Contributor
timestamp: June 15, 2022, 04:20:24 pm
content: I would assume missing packets. It is easy enough to test if you control the device firmware. Make it just a dummy device with no endpoints (or just change everything to be vendor specific). The goal is to not have host send any packets other than SOF. If it does not detect disconnect in this case, then it is based on packet loss.

author: SiliconWizard
author_rank: Super Contributor
timestamp: June 15, 2022, 06:34:48 pm
content: Yes, failing to decode proper response packets within the max timeout allowed by the protocol would likely yield to the host just ending the connection.Depending on the OS, for this condition of expected packets not received, I would expect that the OS would detect a "device malfunction" and then disconnect it, rather than just disconnecting it as though the device was just unplugged, without noticing any error. At least with Windows, you'd likely get such a message.Now, while it does sound a bit unlikely here, it could also be that the line state detection would occasionally see two low states for D+ and D- due to too much attenuation, and thus detect a device unplugged condition.

author: dpai
author_rank: Newbie
timestamp: June 16, 2022, 11:19:17 am
content: Thanks for your inputs! I will follow ataradov's suggestion to verify.
USB 2.0 long stubs versus improper impedance matching - Page 1
Forum section: electronics / projects

author: funkathustra
author_rank: Regular Contributor
timestamp: August 04, 2015, 07:28:39 pm
content: I'm trying to lay out a USB type-C connector on a two-layer board, and I need to connect both sides of the connector to the data traces. The traces cross over, which means a two-layer layout is required. I'm trying to figure out which is better:route the diffpair straight to one set of contacts, and then drop two vias to route a second diffpair to the second set of contacts. Problem: really long unterminated stubs, since the second diffpair has to wind all the way around to get to 180 degree.Route the diffpair straight to one set of the contacts, then continue one of the traces to the other set of contacts, while dropping a via on the other track. Probably: impedance matching goes out the door since one side of the diffpair is staying on the top layer, while the other is jumping around.I'm leaning toward option 2:I've length-tuned it using xSignals so both diffpairs are properly matched.Any thoughts?

author: nctnico
author_rank: Super Contributor
timestamp: August 04, 2015, 07:34:59 pm
content: That is not going to work because you'll have a long stub. Connect B7 and A7 using a short trace and 2 vias.

author: funkathustra
author_rank: Regular Contributor
timestamp: August 04, 2015, 07:38:01 pm
content: And ignore length-matching? The path from pin 5 to B7 is going to be longer than the path from pin 4 to B6.EDIT: I didn't mention, but this is only USB 2.0 full-speed, not high-speed or USB 3.0/3.1 stuff.

author: Monkeh
author_rank: Super Contributor
timestamp: August 04, 2015, 07:38:50 pm
content: Quote from: funkathustra on August 04, 2015, 07:38:01 pmLonger by enough to skew the signal significantly?What does the difference come to, 2-3mm?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 04, 2015, 07:56:06 pm
content: After a metre or two of out-of-spec dodgy Chines USB cable, a few mm isn't going tom make a difference.Less so for USB Full-speed at 12Mbits. You could get away with Veroboard for that

author: TiN
author_rank: Super Contributor
timestamp: August 05, 2015, 04:14:19 am
content: That's wierdest diffpair I sawJust route DP from connector to pair of vias.Then on same layer your DP going to nearest pinsAnd on bottom layer DP is going opposite side, make a U-turn and go to far pins via another pair of via's.You will have extra 2 vias on lane, but that would be better than current arrangement. And you still can match impedance and length if your reference plane uniform on both layers.

author: amyk
author_rank: Super Contributor
timestamp: August 05, 2015, 07:13:57 am
content: The biggest question I have is why are you using USB-C for 2.0FS?

author: funkathustra
author_rank: Regular Contributor
timestamp: August 05, 2015, 07:20:39 pm
content: Quote from: amyk on August 05, 2015, 07:13:57 amBecause you can plug the cable in using either orientation, and when I plug USB micro cables into devices, I get it wrong 90% of the time (I know, a statistical impossibility).That's honestly the only reason.
USB 2.0 MOV/ESD/protection - Page 1
Forum section: electronics / projects

author: Renate
author_rank: Super Contributor
timestamp: October 08, 2020, 10:15:10 pm
content: These things appear quite common but I can't seem to find the right keyword to find them.It's a 4 pad SMD with the ground tab fatter. The pad across from it is the 5V (Vcc) tab, the other 2 tabs are the 3.3V (D+, D-) tabs.I see one that says "C06yN" and one that says "C06pJ" and one, maybe "WF1"I think that is an SOT-143?Any hints?Oops, forgot to post the photo!

author: KT88
author_rank: Frequent Contributor
timestamp: October 08, 2020, 11:12:23 pm
content: Semtech is one manuafacturer of these parts:https://www.semtech.com/products/circuit-protection/usb-20these are TVS based. I've seen SCRs as well...but that might have been with other differential interfaces...CheersAndreas

author: Renate
author_rank: Super Contributor
timestamp: October 09, 2020, 12:12:44 am
content: A good idea, but there is nothing 4 pad there.How about this regulator IC?It's off the USB bus too and probably blown sky high also.

author: steenerson
author_rank: Newbie
timestamp: October 09, 2020, 12:31:14 am
content: I've used these, Mouser has them under "Circuit Protection > ESD Suppressors / TVS Diodes", search for SOT-143 and most of the results should list USB 2.0 in the datasheet and be mostly interchangeable

author: dkonigs
author_rank: Regular Contributor
timestamp: October 09, 2020, 11:15:00 pm
content: Yeah, I was just remembering again today that these are a perfect example of a category of specialty component you won't know how to find via any sort of DigiKey parametric search. As someone else already mentioned, Semtech makes these sorts of things.(I first discovered this on a previous project, when stumbling across a Semtech product that provides TVS protection and pull-up resistors for SD card slots. It was great to be able to reduce what many dev boards did in a dozen discrete parts down to a single component.)

author: Renate
author_rank: Super Contributor
timestamp: October 10, 2020, 01:02:37 am
content: Quote from: Renate on October 09, 2020, 12:12:44 amWell, I just chopped the dang thing out and threw in one of those 3.3V TO-92 linear regulators. Done
USB 2A charging requirements  - Page 1
Forum section: electronics / projects

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: September 25, 2019, 11:10:25 pm
content: It is my understanding that most non-fast charging USB phones and devices can charge at a max rate of 2A and 5V from a USB socket.If that is the case, what are the requirements to get faster than 0.5A charging which is standard on most USB 2.0 devices?The reason I ask is because I am building my own power bank with 4 non-fast charging outputs but would like the ability to charge a device at its maximum rate will keeping the output voltage 5V.Currently I am using short (20 cm) 24 AWG wires to wire up the USB plugs and very short and high quality USB cables to charge my Galaxy S10 but I am only able to charge it at around 500 mA when almost empty while a regular 2A USB wall charger could provide it with such current levels.Is there some kind of handshaking process to allow for faster charging rates that I am not aware of?

author: langwadt
author_rank: Super Contributor
timestamp: September 25, 2019, 11:23:58 pm
content: https://electronics.stackexchange.com/questions/177788/how-do-i-design-a-2a-or-more-power-supply-for-my-consumer-usb-devices

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: December 02, 2019, 03:57:23 pm
content: Will this board do the job?https://www.aliexpress.com/item/32922833773.html?spm=a2g0o.productlist.0.0.35905676Jpajjw&algo_pvid=d47917bb-6d82-47ac-a316-235dd001f6d4&algo_expid=d47917bb-6d82-47ac-a316-235dd001f6d4-1&btsid=73719a91-d95b-4349-9ee7-75fba79d498a&ws_ab_test=searchweb0_0,searchweb201602_6,searchweb201603_52

author: GromBeestje
author_rank: Frequent Contributor
timestamp: December 02, 2019, 06:20:28 pm
content: Short the D+ and the D- (the middle pins) in the USB connector on the charger.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: December 02, 2019, 06:38:15 pm
content: Quote from: GromBeestje on December 02, 2019, 06:20:28 pmThanks for that! I am only able to charge at 1A though.Still not clear how to pull 2A from the port.

author: tooki
author_rank: Super Contributor
timestamp: December 04, 2019, 12:48:10 pm
content: Quote from: drummerdimitri on December 02, 2019, 06:38:15 pmThen try readingallthe replies you’ve gotten.I checked and this one explains it:Quote from: langwadt on September 25, 2019, 11:23:58 pm
USB 3.0 Bit rate? What's the actual bit frequency? - Page 1
Forum section: electronics / projects

author: hazuki
author_rank: Contributor
timestamp: February 01, 2021, 06:32:26 pm
content: Hi all,What "frequency" does USB3.0 exist at? I'm looking at insertion loss and I don't know exactly which frequency to pick for USB3. I *think* it's 2.5GHz?From what I understand, the raw bit rate for USB3.0 is 5 Gbit/s. And that is before decoding at 8b/10b. Is this 5Gbit/s data rate a rating for one way or duplex communication? In other words is the data rate 5Gbit/s in both directions simultaneously or 2.5Gbit/s in both directions simultaneously?Thanks for your time!

author: mck1117
author_rank: Contributor
timestamp: February 02, 2021, 12:12:50 pm
content: If you look at a USB 3 cable, you'll notice there are three twisted pairs: one for usb 2.0, and one for superspeed in either direction. 5gbit/s on the wire, full duplex. The actual line signal rate is 5gbit/s. One bit is 200ps long. After 8b10b you're left with 4gbit usable before protocol overhead etc.

author: hazuki
author_rank: Contributor
timestamp: February 02, 2021, 03:17:50 pm
content: I guess my question is: At what frequency do you evaluate the system to get an insertion loss stackup? The insertion loss budget for USB3.0 is 20dB as per the USB3 spec.
USB 3.0 C socket Superspeed with no flipping feature - Page 1
Forum section: electronics / projects

author: nachus001
author_rank: Contributor
timestamp: January 04, 2024, 01:19:59 pm
content: Dear all:I have a question. I have to make a design with and USB 3.0 socket, and the design needs to work with Superspeed USB3 capabilitiesbut, due to space limitations, I cannot add a USB3 UFP mux chip (HD3SS3220, PI5USB30213A and the likes)However, I would't have problem losing the connector flip ability, if I can retain the Superspeed capability.I've implemented USB2.0 functionality using USB3-C sockets in the past and they worked like a charm. Flippable and not flippable implementationsMy question is if a superspeed USB3.0 interface can work at Superspeed in only one connector position without having problems or defaulting to an USB2.0 connection.I've read the USB documentation (lightly I have to admit) and it doesn't says nothing about this one. I guess this is kind of a hack.Do you have any experience in this kind of "partial" implementations? Thx in advanceCheersNachus

author: wraper
author_rank: Unknown
timestamp: January 04, 2024, 01:37:00 pm
content: The workaround to not have mux chip is only possible if the chip you want to connect to USB-C connector has two separate USB3.0 interfaces.

author: nachus001
author_rank: Contributor
timestamp: January 04, 2024, 02:29:14 pm
content: Hi WraperQuote from: wraper on January 04, 2024, 01:37:00 pmI need two interfces even if I don't need the plug flip capability? I need the interface to work with the connector in one position only.Nachus
USB 3.0 hub cheaper than redrivers? - Page 1
Forum section: electronics / projects

author: technix
author_rank: Super Contributor
timestamp: March 09, 2018, 05:25:58 pm
content: I was designing some item that required some signal reshaping on USB 3.0, so I am looking at signal redrivers. To the best of what I can find, redriver chips are much more expensive than a 4-port hub. I know that using a hub here works too as it stores and retransmits the data, but still I was baffled by the pricing. Why is it so?(Although I am expanding the design so I am not wasting ports on the hub, besides the original port I am also bringing out the three additional ports, one as USB Type-A, one as USB Type-C, and the other being used for internal firmware upgrading.)

author: wraper
author_rank: Unknown
timestamp: March 09, 2018, 05:28:52 pm
content: I'd guess hub chips have way higher production numbers.
USB 3.0 Hub - Page 1
Forum section: electronics / projects

author: raptor1956
author_rank: Frequent Contributor
timestamp: February 23, 2017, 08:30:54 pm
content: It seems that USB 3.0 hardware can be pretty flaky with respect to interference and I've experienced some of that myself. My mouse and keyboard connect to my Win10 PC via a wifi dongle that plugs into a USB port but I get frequent issues with the mouse getting jerky and slow to respond and sometimes locking up entirely. So, I unplug the wifi dongle and move it to a different USB port and all seems fine for a while but sooner or later the problem comes back.Early on I had the wifi dongle plugged into a USB port at the back of the PC -- a port that comes right out of the MB connector interface and that gave me huge problems. I then moved the dongle to the USB hub in my display and that helped a lot but isn't without problems either. I have also tried a USB port at the top of the PC case -- a port that came with the case and connects to the MB and that tends to be even more of a problem particularly if I have another device plugged into the same group of USB ports.So, a little poking around with Google reveals that USB 3.0 is a noisy beast and MANY people are having problems. I have to wonder how the FCC and other governments around the world permit such a noisy system to exits, but beyond that, I'm looking for some solution to the problem. I'm not sure it the cables that connect the MB to the USB ports is acting as an antennae or if the noise is coming more directly from the MB but are there any decent USB 3.0 hubs that shield things better?Brian

author: Benta
author_rank: Super Contributor
timestamp: February 23, 2017, 10:09:25 pm
content: Dunno where you live, but have you thought about how many other WiFi transmitters are in the vicinity?Solution: keyboard with cable, mouse ditto. Works everywhere.

author: Monkeh
author_rank: Super Contributor
timestamp: February 23, 2017, 10:44:47 pm
content: And in all this.. where's the USB 3?

author: suicidaleggroll
author_rank: Super Contributor
timestamp: February 23, 2017, 10:51:26 pm
content: From your description it sounds like the mouse/keyboard simply have some serious problems, why do you think it's related to USB 3 or EMI?
USB 3.0 USB C Reversible Connection , Why mux is needed? - Page 1
Forum section: electronics / projects

author: RoadRunner
author_rank: Frequent Contributor
timestamp: July 09, 2020, 08:52:31 pm
content: I am working on a project targeting to achieve USB 3.0 USB C reversible connection, After searching on web i found that quite a few schematic shows solution using of USB 3.0 Mux.While USB 2.0 the just short both of D+ together and also D- together. As shows in a reference schematic. For usb 3.0 a mux is used.My guess is using mux, Routing of Ghz range signal will be easier.My question is this just for better routing for USB3.0 lines or there a specific reason for Having a dedicated mux.Because i guess if short RX2+ to RX1+ and so on, It should work?Regards

author: langwadt
author_rank: Super Contributor
timestamp: July 09, 2020, 09:28:45 pm
content: the same reason that before the gigabit ethernet standard you needed crossover ethernet cablesusb 3.0 use a pair for each direction, the two ends have to agree on which pair each end transmits on and swap so rx goes to txusb 2.0 does both directions on a single pair

author: jbb
author_rank: Super Contributor
timestamp: July 09, 2020, 10:22:56 pm
content: As I understand it, the USB SuperSpeed signals are some GHz and need to be routed really carefully to maintain signal integrity.Simply tying the superspeed pairs together will create a transmission line stub and impair the signal integrity. This could result in failure to pass certification tests, or unreliable link behaviour or maybe total failure.If you can get by with USB Hi Speed (480 Mb/s) then life is easier...
USB 3.1 Standard A to Type C Pinout? - Page 1
Forum section: electronics / projects

author: Northy
author_rank: Regular Contributor
timestamp: December 02, 2020, 08:50:13 pm
content: I'm really struggling to find this!Does anyone know where I can find the pinout (or is it pin through?) information on how a USB 3.1 Standard A to Type C cable is connected up?I think the cable is: AC3G2-3I found that in the USB spec.I've got a board with a TI mux on it, and I'm struggling to work out what the CC1 and CC2 pins should be doing when it's plugged into a PC USB 3 port.Cheers,G

author: poorchava
author_rank: Super Contributor
timestamp: December 02, 2020, 09:18:57 pm
content: IIRC, the cable should have a 56k pull-up to 5v inside. The 5v on usbc is different than vbus, but for legacy usb vbus is always 5V. AFAIK stuff like QuickCharge is in violation of the usb standard, which forbids additional charging protocols and changing of vbus voltage.

author: thm_w
author_rank: Super Contributor
timestamp: December 02, 2020, 09:30:49 pm
content: https://cdn57.androidauthority.net/wp-content/uploads/2018/07/USB-Types-and-Pins-Explained.jpgQuotehttps://www.reclaimerlabs.com/blog/2017/1/12/usb-c-for-engineers-part-2https://www.usb.org/sites/default/files/USB%20Type-C%20Spec%20R2.0%20-%20August%202019.pdfedit: Rp to pullup to Vbus as mentioned above.

author: Northy
author_rank: Regular Contributor
timestamp: December 03, 2020, 07:34:56 pm
content: Thank you, that's great, I found the information in the USB.org document.I've been looking for different variants of cables to buy today to test and I'm shocked that many Type C cables are just USB 2.0 (4 wire) and can get very expensive! A trap for young players as Dave would say!Thanks,Graham
USB 3.2 Type C pin swapped - Page 1
Forum section: electronics / projects

author: fedimakni
author_rank: Regular Contributor
timestamp: February 18, 2025, 09:49:36 am
content: HelloI found a schematic of a dev board that has a connection between USB type C (KUSBX-SL2-CS1N24-B-TR) and a 10Gbps Mux (PI5USB31213AXEAEX). I was trying to recreate the schematic but i found that as you can see in the attached picture some pin are swappedSSTXn2 pin is connected to A2p (swapped)SSTXp2 pin is connected to A2n (swapped)SSTXn1 pin is connected to A2n (correct)SSTXp1 pin is connected to A2p (correct)the same for the RX side.I didn't understand if that is intentional and the mux can handle that swap or a mistake. It seems the board operate as expected but i couldn't probe the pins as they are very smallThank you very much

author: Ice-Tea
author_rank: Super Contributor
timestamp: February 18, 2025, 11:55:44 am
content: The specification allows for that to facilitate routing.

author: fedimakni
author_rank: Regular Contributor
timestamp: February 18, 2025, 12:10:35 pm
content: Do you need to implement something on the SW side to match that?

author: macboy
author_rank: Super Contributor
timestamp: February 20, 2025, 04:58:05 am
content: PCIe, SATA, and ethernet can also have polarity of their differential pairs reversed at will. The hardware handles it transparently. No need for software to do anything.Type C is even more complicated though, because the connector can be reversed, which swaps pairs around, rather than just inverting polarity of individual pairs.
USB 3 cable (Mouser or Farnell) - Page 1
Forum section: electronics / projects

author: timgiles
author_rank: Regular Contributor
timestamp: September 29, 2016, 01:33:59 pm
content: Hi,Hoping for some direction on what search terms to use to find USB cabling. Not premade cables, but the actual cable. Looking to buy from Mouser or Farnell.Thanks in advanceTimothy

author: Monkeh
author_rank: Super Contributor
timestamp: September 29, 2016, 01:39:23 pm
content: The search term would be 'USB'. There really is no other description, it is not generic cable.