hybridfree/eevblog-posts huggingface dataset:
PCB voltage insulation - Page 1
Forum section: electronics / projects

author: tekman11
author_rank: Contributor
timestamp: May 08, 2015, 01:03:06 pm
content: Is it expectable to run a low voltage trace on the inner layer. the top/bottom carries AC max 275v.The low voltage trace is routed on ground plane. the power plane is un-routed.I'm concern about arcing between top and ground layer.The PCB stack up: top, gnd, power, bottom. The distance between top and ground is ~28mils.The two layers are separated by prepreg. The construction is FR4.thanks

author: Rerouter
author_rank: Super Contributor
timestamp: May 08, 2015, 01:17:27 pm
content: I went digging, and accounting for aging effects, FR4 still has a dielectric breakdown voltage of 300V per mil, so would seem you are fine to do so,http://www.magazines007.com/pdf/High-Voltage-PCDesign.pdf

author: Zero999
author_rank: Super Contributor
timestamp: May 08, 2015, 06:40:50 pm
content: Don't forget that in order to comply with the regulations for reinforced insulation, it must be able to withstand much higher voltages, up to 6kV if I remember rightly, so 28 thou is probably the minimum thickness.I hope you're also aware of the creapage and clearence requirements.
PCB vs oven cleaner, is it safe? - Page 1
Forum section: electronics / projects

author: bill_c
author_rank: Regular Contributor
timestamp: May 16, 2023, 04:59:00 am
content: I sprayed half of an old PCB with oven cleaner and let it set for an hour as a test, rinsed and dried, and it looks fine. Are there any known problems with using oven cleaner on populated boards?Or is there a better way to get that sticky gel like goo off of restaurant equipment?

author: Someone
author_rank: Super Contributor
timestamp: May 16, 2023, 05:14:52 am
content: Quote from: bill_c on May 16, 2023, 04:59:00 amLimonene/citrus solvent.

author: johansen
author_rank: Super Contributor
timestamp: May 16, 2023, 05:49:40 am
content: Quote from: Someone on May 16, 2023, 05:14:52 amThe only chemical that a friend of mine found that was effective at dissolving the goo left behind on vw jetta engine parts on a vehicle run on straight waste veg oil.. was wd40.Goo gone didnt dissolve it. Now im talking about the tar like substance left behind in the tank, in the injection pump, on the fuel injectors (plugging up all the inlet holes until they warmed up). We ran the car nearly empty and dumped a gallon of wd40 in it.. runs great now.

author: barshatriplee
author_rank: Regular Contributor
timestamp: May 16, 2023, 08:45:50 am
content: The chemicals in oven cleaners can react with various materials on the PCB, including solder masks, traces, and component coatings. This can result in discoloration, corrosion, or even complete failure of the components or the board itself. In my opinion, it should be avoided.

author: mikerj
author_rank: Super Contributor
timestamp: May 16, 2023, 12:43:19 pm
content: Most oven cleaners contain lye (aka sodium hydroxide or caustic soda) which is pretty harsh stuff. It attacks aluminium quite readily and will also dissolve zinc and lead, though quite slowly at room temperature with typical over cleaner concentrations. I would not be using it on PCBs personally.

author: coromonadalix
author_rank: Super Contributor
timestamp: May 16, 2023, 04:24:26 pm
content: i found out a brake cleaner in spray (done some tests) who worked wonders, with no residuesWas better than the chemtronics smell like hell pcb wash and another brand i dont want to recall who smelled very bad for a loooooong time even with good ventilationNow i use Atron SC205 at 5% concentration work very wellAt stronger concentration i even cleaned some mechanical parts lolll was good to to clean floors loll

author: wraper
author_rank: Unknown
timestamp: May 16, 2023, 04:30:38 pm
content: There are different oven cleaners. Some are relatively harmless, others eat away aluminum, and likely some other metals.

author: bill_c
author_rank: Regular Contributor
timestamp: May 16, 2023, 06:56:26 pm
content: Thanks everyone. I tried the cheap stuff from dollar store, no damage to silkscreen and no visible corrosion, doesn't mean its safe, and not all brands are the same. I will look for those other cleaners listed above and try a few of them before I try cleaning anything expensive.
PCB with multiple DC voltage levels: How to filter, ground and connect 0V - Page 1
Forum section: electronics / projects

author: mike buba
author_rank: Contributor
timestamp: September 11, 2019, 05:33:04 pm
content: Hi,I am trying to design a PCB with different voltage levels (each one coming from a different DC/DC converter located on the PCB). Levels are +/-15V, 12V and 5V. The example I am looking has some inductors and capacitors added at the output.How are they selected?I was not able to find any recommended components in Traco Power datasheet for TEN 6 DC/DC Converter. I have also found example with several arallel capacitors between Vdc and 0Vdc.Also,can I combine different 0Vdc?In DC/DC converter this isCOMMONoutput (e.g. each one for 15Vdc, 12Vdc and 5Vdc converter)? Is it just matter of connecting them directly, or it is not that easy?What to do with the ground (PE).Is 0Vdc(COMMONoutput)same as PE?I.e. can I short-circuit them? Or again, this is not that simple/advisable or is there is a better solution?Thanks and apologies for combining few question under one thread
PCB with soldermask under uC pins: unsoldered mechanically floating pins  - Page 1
Forum section: electronics / projects

author: Kjelt
author_rank: Super Contributor
timestamp: February 01, 2017, 08:43:09 pm
content: Hi perhaps some of you diehards have seen this before, I haven't and am greatly surprised.Today I opened a commercially available device that I got from a friend: a Meanwell DAP-04 protocol converter.To my surprise 19 pins on the LPC1114F microcontroller were unsoldered.Those pins had no pads under them just soldermask so they are totally clean and are mechanically floating above the pcb.Why?The only reason I can think of is to save $0,001 on solderpaste.The drawback is that the uC is less stable attached to the pcb, and hopefully those pins are defined as output low else if they are defined as floating input it can destroy the uC.Has anyone seen this before and have a viable explanation why a decent manufacturer like Meanwell would do something like this ?Sorry the picture is not better, I do not have a foto option on my stereo microscope and the macro setting on my camera would result in less detail, hope you can see it clearly.

author: Kjelt
author_rank: Super Contributor
timestamp: February 01, 2017, 08:50:00 pm
content: This picture might be somewhat better.

author: thm_w
author_rank: Super Contributor
timestamp: February 01, 2017, 09:02:12 pm
content: Quote from: Kjelt on February 01, 2017, 08:43:09 pmI wouldn't be too concerned about it falling off, I've never seen a TQFP pop from the board. BGA's sometimes. Also there is not much concern about floating input on a uC destroying it, even though it is best to set as output in software. If this was wave soldered, I can see they would want to do it to reduce shorts/reworks. Same could apply to reflow but would be less likely.I've seen a few times on chinese designs, it is quite odd.

author: Kjelt
author_rank: Super Contributor
timestamp: February 01, 2017, 09:11:24 pm
content: Quote from: thm_w on February 01, 2017, 09:02:12 pmAh yes that would be a good reason, it is a mixed technology board (so also TH components).The bottomside the smt components are all glued so could be the case.Although they probably would be better off using each other I/O pin instead of a couple next to eachother, thereby reducing the risk even more.Nice board though, lots of isolation slots routed.
PCBA thermal analysis System - DYT CA20 + SpectrumOwl Software - Page 1
Forum section: electronics / projects

author: Fraser
author_rank: Super Contributor
timestamp: January 14, 2022, 01:00:36 pm
content: This post is for those who work in R&D but who do not frequent the thermal imaging area of this forum.As some may know, the thermal imaging camera can provide some very useful imagery and measurements when designing or diagnosing issues with a product. I use thermal cameras in fault finding and assessment of PCBA thermal energy dissipation.I reviewed a dedicated PCB thermal analysis system a while ago and was very impressed with its capabilities, especially when compared to the more expensive FLIR ETS320. I now own that Review sample and it gets a lot of use on my lab bench. That system is the DYT CA10 SpectrumOwl but DYT have just released another model to add to their PCB thermal analysis range. The new model is the CA20 and this offers a motorised mount, higher temperature measurement capability (-10C to +450C) and an enhanced PCBA Analysis software package. I am currently testing the new software in order to provide user feedback to DYT so that it may be further improved.This is not an advert, just a ‘heads-up’ for those who might have a use for a reasonably priced PCBA thermal analysis system that may also be used for other thermography activities, if desired. I am certainly very happy with the CA10Take a look at my review of the CA10 for the images and video that I captured from my CA10 when viewing modern PCBA’s and tiny SMD resistors. I even imaged insects with it !The link to the DYT posting on the thermal imaging forum……https://www.eevblog.com/forum/thermal-imaging/dytspectrumowl-ca-20-electronical-version-on-kickstarter-crowdfunding/Fraser

author: Fraser
author_rank: Super Contributor
timestamp: January 14, 2022, 01:05:32 pm
content: My review of the CA10 PCBA analysis system. The CA20 uses the same imaging core and manual focus lens so the captured imagery remains valid fir the CA20. The CA20 uses a very nice imaging core from China that is capable of up to 25fps.https://www.eevblog.com/forum/thermal-imaging/review-dianyang-technology-ca10-circuit-board-thermal-analyzer-repair-rd/Fraser

author: Fraser
author_rank: Super Contributor
timestamp: January 14, 2022, 01:12:57 pm
content: For those unaware of what a thermal imaging camera can offer in terms of PCBA analysis, take a look at this threadhttps://www.eevblog.com/forum/thermal-imaging/use-of-a-thermal-camera-for-pcba-thermal-profiling-and-repair/Fraser
PCB/cable isolation from aluminum enclosure - Page 1
Forum section: electronics / projects

author: jmaja
author_rank: Frequent Contributor
timestamp: September 11, 2013, 01:31:19 pm
content: I'm designing a measuring device, which will be inside an aluminum enclosure, which will be grounded to main earth. The device will have 24 Vdc and RS-422 data cables, which are and need to be isolated from main earth, but not from each other.Can I just have the whole PCB GND floating at 24 Vdc negative? Will this introduce severe problems for ESD/EFT/surge protection?The PCB, which has the sensors, needs to be very firmly attached to the enclosure and space is limited, thus I will have PCB GND only a few mm from attachment screws and also the enclosure itself.

author: Kremmen
author_rank: Super Contributor
timestamp: September 11, 2013, 02:34:39 pm
content: You could have a Y cap from the secondary side supply and signal ground to PE. That would provide a HF path to ground but maintain galvanic isolation.

author: WarSim
author_rank: Frequent Contributor
timestamp: September 11, 2013, 03:02:06 pm
content: If you can guarantee the "few mm" are maintained you have said nothing that would be concerning. Of course this would depend on vibration, PCB flex and max isolation potential. Every isolated device has an isolation voltage limit you need to decide on yours, then make sure you minimum guaranteed air gap is sufficient. There is the option of using an insulator film or tape if you need more isolation.

author: jmaja
author_rank: Frequent Contributor
timestamp: September 11, 2013, 09:40:33 pm
content: I can easily guarantee 2 mm is maintained, with some extra tought I could probably get 4-5 mm.I don't need a high isolation voltage limit, 1 kV is more than enough for isolation tests and normal operation and 2 mm should be enough for that.What I'm worried about are the ESD and EFT tests. The device needs to pass 8 kV air, 6 kV contact ESD and 2 kV EFT and 1 kV comon mode surge. These may cause an arc between the enclosure and PCB. I don't know how bad that could be for the unprotected chips on the PCB. The power supply and 422 chips have external TVS diodes, but not the microcontroller, ADC etc on the other side of the PCB.Would an Y cap solve that? Where should it be put?
PCBCart panel ordering help? - Page 1
Forum section: electronics / projects

author: drwho9437
author_rank: Regular Contributor
timestamp: December 17, 2010, 12:59:01 pm
content: I posted a while back about makePCB, but I have changed my mind about using them I think because of the one time nature of the setup fee at PCBcart.I know Dave and others have used PCBcart, but I find the quote confusing a bit for a panel given how bad the English is I thought it better to ask here than them directly.Panel is 6 copies of the same PCB with v-score. The full panel has 468 vias.They say:"If need panelized board please select "Board type" as "Panel" and input board dimension as "Panel dimension", if have file for single unit only please panelize it or contact us for panelization before order "There is no panel dim, just board dim. I select panel and put in my board dim 244 mm x 168 mm.Different design in panel: I select "1" I presume this is the number of different sub-designs not the number of instances.? (Is it??)Route Process: Panel as V-scoring.Taking the defaults, change surface finish to ENIG.Holes number: Change to 300-600?? (I assume Vias count as holes and the count is per panel?)I think everyone else is default except change in color.I was going to send a "comment" gerber layer to show where to v-score. I backed the v-score 1 mm from the copper plane. Is that enough for the width of a v-score from them?I apologize for all the questions, but I am poor and this will cost a lot and is my first panel. I would ask them but fear a confusing answer is all I will get due to language.

author: Simon
author_rank: Unknown
timestamp: December 17, 2010, 01:26:44 pm
content: why not contact them and tell them to sort out their ordering system, poor english is to my mind a sign of a dodgy service

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 17, 2010, 01:38:14 pm
content: Quote from: drwho9437 on December 17, 2010, 12:59:01 pmThis is the size of the full panel, i.e. PCB dim * repeats+spacing+bordersQuoteYes - this is probably for testing setupQuoteYesQuoteYes - you should include a layer that has board outline, cutouts and score positionsQuotePCBCart will usually query anything they can't figure out or things that look unusual. Worth bearing in mind if leadtime is tight.AFAICS about the only difference between panel and single unit is the number of repeats for testing purposes.If there are failures, the faulty PCBs within the panel will be crossed out in ink. This can sometimes work in your favour as they will always ship the number of individual boards ordered, so if one fails you may get a whole extra panel.

author: drwho9437
author_rank: Regular Contributor
timestamp: December 17, 2010, 02:33:31 pm
content: Thanks very much Mike! Lead time is a minimal issue for me. I have very little free time to work on these things. It seems my best guesses were correct, but I felt it wise to check. Good to know they ask rather than just running it.
PCB's of Ampslab C300 Class AB amplifier - Page 1
Forum section: electronics / projects

author: profdc9
author_rank: Frequent Contributor
timestamp: August 30, 2020, 08:05:22 am
content: I am working on building a stereo amplifier using the C300 amplifier of Michael Chua of Ampslab. It is a Class AB BJT-based stereo amplifier capable of 300 watts per channel. I have the PCB's on my github athttps://github.com/profdc9/PowerAmpAudioYou can read about the C300 athttps://ampslab.com/c300.htmhttps://ampslab.com/c200.htmThere are four PCBs in the project so far:1. C300 amplifier PCB2. Power supply rectifier and filter3. Soft start PCB for toroidal transformer and capacitor bank4. Balanced XLR to unbalanced input for the amplifierThe schematics and gerbers are all there as well as BOMs with component part numbers mostly from LCSC.com , with a few digikey and Mouser parts as well.We have ordered all of the stuff and are going to photodocument the build. As an example I have a screenshot of the PCB.Dan

author: ghubbell
author_rank: Newbie
timestamp: April 20, 2021, 07:18:47 pm
content: Hello Dan, any possibility to purchase some PCBs please?

author: magic
author_rank: Super Contributor
timestamp: April 20, 2021, 07:40:02 pm
content: I know it's a necro thread, but...Is it just me or does the VAS overcurrent protection scheme (Q9 and thereabouts) look a little fishy?As in, it's gonna blow up Q8

author: floobydust
author_rank: Super Contributor
timestamp: April 20, 2021, 09:57:32 pm
content: R19 is only 10R so I don't expect Q9 to turn on until things are smoking. It seems to be 33R in the updates, but still very high current.These copies of Self's Blameless design are plentiful and it's missing a Baker clamp, will hang up if driven into clipping and compensation capacitors everywhere usually mean the stability is not as needed.I'd expect VAS Q8 to get damaged, other copies of the Blameless added a current-limiting resistor on its collector as well as a Baker clamp for it.Essential on the PCB layout is taking NFB right off the output, not a long pcb trace away as the design should be able to do better than 0.01% THD.
PCBs... - Page 1
Forum section: electronics / projects

author: prasimix
author_rank: Unknown
timestamp: January 18, 2015, 10:31:30 am
content: ... and PCBs ...

author: prasimix
author_rank: Unknown
timestamp: January 18, 2015, 10:32:33 am
content: Admin/moderator please move this one here ...https://www.eevblog.com/forum/projects/diy-programmable-dual-channel-bench-psu-0-50v3a/
PCD Board light - Page 1
Forum section: electronics / projects

author: kaugustino
author_rank: Newbie
timestamp: October 20, 2019, 04:25:31 am
content: I want to build a PCB board flashlight. Using a bunch LEDs. Something like one of the Led 3 or 4 led type push lights. With capacity to be either ran on batteries or usb. I need some advice to get started. i would just get built from one of the online PCB sites. I have limited electrical experience. Mostly basic circuits stuffOn batteries i would like to use a lot of batteries (3-4 AA batteries). Basically something i could use for a while without changing them. Something bright enough i could use as a nightlight. With a rocker style on/off switch. Or something big/easy to use. I have a basic design idea. at this point board size/shape does not matter. I'm not considering to sell them. Just something custom for myself. Any designs i will let anyone use.

author: kaugustino
author_rank: Newbie
timestamp: November 03, 2019, 05:27:06 am
content: So i want to build something like a LED Puck light. Those 3 led lights that you just push on the top to light it up. But i want to change that out to a rocker style on/off switch (Ease of use) But instead of using just 2-3 AA batteries i would like to add maybe double the batteries (or run it off an pocket usb charger) and more ledsIs their a basic design i can use as a template to start?

author: kaugustino
author_rank: Newbie
timestamp: November 03, 2019, 05:39:53 am
content: My crappy drawing attemptLEDs could also be circular. Does not matter.

author: bob91343
author_rank: Super Contributor
timestamp: November 03, 2019, 06:06:30 am
content: There are two basic approaches. The first, and simplest, uses resistors or constant current devices to limit LED current. Not too efficient but widely used.The second uses a complex switching circuit that accomplishes the same thing but wastes much less energy. This translates into longer battery life.The best scheme treats each LED separately. You can also put them in series but making the current constant is a bit more of a challenge due to the limited overhead voltage from AA cells.
PCF7961 car key programming - Page 1
Forum section: electronics / projects

author: rvalente
author_rank: Frequent Contributor
timestamp: March 06, 2020, 04:24:21 pm
content: Hello Mates,I own a 07 peugeot 307, with one remote key and I wish to add a second one.To match the key to the car, I have the peugeot dealer equipment and software, thats the easy partThe problems rely on the key itself, which is based on the philips/nxp PCF7961. The internal eeprom must be programmed with a dump to be read by the car as a virgin key and after matched to the car this eeprom is "locked" them the key can't be reused in another car.I was given a working key from a scraped car, but need to reflash the eeprom with the original dumpThe remote board:There are some specialty programmers that can read and decode the PCF7961, but I do not have one of those, ehis IC is I2C based.Does anyone know any procedure to read and reprogram this IC with a simpler programmer? Bus pirate or arduino sketch?
PCF8591 Obsolete - Page 1
Forum section: electronics / projects

author: Shocking
author_rank: Newbie
timestamp: November 19, 2019, 11:43:39 pm
content: I want to an AD DA converter for my Raspberry Pi. The PCF8591 chip was popular a couple of RP generations ago.Today, some parts suppliers claim that thePCF8591AD DA Converter chip is obsolete. The DIP version sells at high prices, if I can find it at all. Does anyone know what chip is meant to replace this I2C IC?

author: ve7xen
author_rank: Super Contributor
timestamp: November 20, 2019, 12:33:12 am
content: It's been discontinued for over 10 years, last order date was 31 Mar 2009.Mostly nobody is making DIP ICs anymore. The SOIC version is still available if you want an equivalent. If you must have through hole, you will probably need to get a separate DAC and ADC. The only cheap converters I can find are SPI, not I2C as well.If you want to breadboard with it, just get the SO16 version and solder it on a DIP16 adapter PCB. Someone is probably manufacturing this, too.

author: ebclr
author_rank: Super Contributor
timestamp: November 20, 2019, 01:32:16 am
content: Still widely availablehttps://pt.aliexpress.com/item/32592826611.html?spm=a2g0o.productlist.0.0.5f6f5fadQxGRYW&s=p&algo_pvid=9640aca9-53e3-4c1c-a4b7-36c6d6f05d2c&algo_expid=9640aca9-53e3-4c1c-a4b7-36c6d6f05d2c-2&btsid=4d1e8dac-ba33-4b79-a4e9-de30c9c247d4&ws_ab_test=searchweb0_0,searchweb201602_9,searchweb201603_52https://s.taobao.com/search?q=PCF8591&type=p&tmhkh5=&spm=a21wu.241046-global.a2227oh.d100&from=sea_1_searchbutton&catId=100
PCI Canbus, looking for a Linux expert for upgrading the driver to kernel >v4.9 - Page 1
Forum section: electronics / projects

author: legacy
author_rank: Super Contributor
timestamp: March 23, 2019, 10:43:52 pm
content: hiwhen you work with a smart robotic-arm, it might happen you need to work with CanBus for controlling it. There some usb-to-can adapters out of there, but they are usually very expensive (250 euro), whilethisproduct often appears on eBay for cheap (30-50 euro). It's an EOL product, but it looks great and comes with a Linux kernel driver as well as a few application-examples with sources and documentation. Unfortunately, it only works for kernel <4, and needs some work for being updated to modern kernels.I'd like to use one of those for a hobbyist project: anyone with strong skills at kernel drivers?

author: Nominal Animal
author_rank: Super Contributor
timestamp: March 24, 2019, 08:39:58 pm
content: Do you have the Linux kernel driver sources? The link you showed requires registration. You could email them to me, perhaps?I can't make any promises (not because of lack of skill, but because of burnt-out brain), but I'm willing to take a look.

author: legacy
author_rank: Super Contributor
timestamp: March 24, 2019, 09:02:09 pm
content: Quote from: Nominal Animal on March 24, 2019, 08:39:58 pmYes, I registered a personal (not business, since the board is for a hobby) account to their website and they kindly allowed me to download sources and examples. I can upload somewhere on DTB and give you the ticket via a private message here (I don't have your email).Quote from: Nominal Animal on March 24, 2019, 08:39:58 pmIt's not a problem, and there is no deadlineedit:super thank you in advance!

author: Nominal Animal
author_rank: Super Contributor
timestamp: March 24, 2019, 09:42:47 pm
content: Quote from: legacy on March 24, 2019, 09:02:09 pmIt's in my profile, and the only thing shownon my web page. But, if you want, a download link via private message is fine too.

author: legacy
author_rank: Super Contributor
timestamp: March 24, 2019, 11:15:17 pm
content: ops. PM sent. I don't know if I can publish the package in public, so if someone needs/wants to read it, please contact me by PM and I will show the link for the download.In the meanwhile, I am going to write to the vendor, asking for the permission

author: legacy
author_rank: Super Contributor
timestamp: March 25, 2019, 10:18:35 am
content: Quotethey replied 5 min ago, explaining a few points and giving me the permission to publish the source (which is GPL, anyway)it can be downloaded fromhere(hosted on DTB).
PCI-e Edge connector Protection - Page 1
Forum section: electronics / projects

author: Eigerdesign
author_rank: Contributor
timestamp: September 06, 2014, 08:07:35 am
content: Dear ForumRecently I purchased a graphic card which had a very sexy PCIe edge connector protector cap.We also sell cards with edge PCIe edge connectors and would really like to ship with such protection caps fitted but cannot find a supplier for "love nor money".We have both 98way and 164way edge connectors.Does anyone know where I can buy these, I think if I rang ASUS they would tell me very politely where to go.Many ThanksTony

author: DanielS
author_rank: Frequent Contributor
timestamp: September 06, 2014, 09:54:07 am
content: They are likely custom so if you want some, you will have to take your mechanical drawings to a plastic molding company and have them custom-made out of ESD-safe/dissipative plastic.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 06, 2014, 04:18:04 pm
content: I guess you looked at Keystone Electronics? Take a close look at the plastic thingy, there might be a logo?Wasn't there a company called Global that made all kinds of plastic doohickeys?
PCI Express 8 Pin (or 6+2) Socket Type - Page 1
Forum section: electronics / projects

author: sleemanj
author_rank: Super Contributor
timestamp: July 27, 2017, 09:17:47 am
content: Does anybody know a model number for the PCI Express 8 Pin (6+2) Socket (pcb through hole)?This is not the same as an 8 Pin Molex Mini-Fit Jr, the two add-on pins not only have a flipped "polarity" (the "square" pin is on the wrong side compared to those locations in the 8 pin) but there is an additional keying bridge between two pins.The 6 pin PCI Express (or just the 6 part of a 6+2) is easy, but I'm having no luck finding any reference to a proper socket for the full 8/6+2
PCI Express GPIO solution - Page 1
Forum section: electronics / projects

author: iceisfun
author_rank: Regular Contributor
timestamp: November 19, 2013, 04:24:39 am
content: Does anyone here know of a good PCIE GPIO card?I would like a card with a port on the back that goes to a gpio breakout board.

author: Jon86
author_rank: Frequent Contributor
timestamp: November 19, 2013, 06:55:47 am
content: Do you mean GPIB? If not, what kind of port are you looking for? There's no such thing as a GPIO Port, as far as I'm aware.

author: kxenos
author_rank: Frequent Contributor
timestamp: November 19, 2013, 07:04:01 am
content: I use thesehttp://www.icpdas.com/root/product/solutions/pc_based_io_board/pc_based_io_board_products.html#PCI.Pretty robust. about 2 boards broken for about 130 PCs for 12 years.

author: Unknown
author_rank: Unknown
timestamp: November 19, 2013, 07:56:20 am
content: Unless you need the extra speed or lower latency, a GPIO interface with USB connection (eg. Labjack) may be a cheaper solution.

author: amyk
author_rank: Super Contributor
timestamp: November 19, 2013, 12:53:58 pm
content: How many bits of GPIO do you need, and how fast?

author: penfold
author_rank: Frequent Contributor
timestamp: November 19, 2013, 01:16:14 pm
content: Something like the amplicon PCIE296 sounds like its what you're after. At 199GBP its cheaper than most Labjack offerings for higher numbers of IO lines (not that a single labjack would give you 96 lines)If you were on regular PCI then the prices are much cheaper

author: jeremy
author_rank: Super Contributor
timestamp: November 19, 2013, 01:36:16 pm
content: You should buy one based on software development practices that you are comfortable with. For example, the NI DAQ cards are nice (but expensive), I really don't like labview though. Good thing they provide ANSI C libs too. I have seen a bunch of cards which were supposed to be used with visual basic (yucky!), if that is not your flavour then don't spend your money.

author: iceisfun
author_rank: Regular Contributor
timestamp: November 19, 2013, 06:22:08 pm
content: Quote from: penfold on November 19, 2013, 01:16:14 pmThat is awesome, exactly what I am after.Thanks for the tip!
PCI Express power connector alternative - Page 1
Forum section: electronics / projects

author: poorchava
author_rank: Super Contributor
timestamp: February 24, 2014, 12:25:43 pm
content: Hi,I need to power a few pcb's from ATX poweri supply via PCI-Express power connector (can be either 6-pin or 8-pin), but I'm puzzled about the type of PCB connector that I need to buy.Only thing I have found is that 6-pin version is Molex 45558-0002 (which is obsolete and -0003 version is recommended). About 8-pin nothing is known.It's hard for me to believe that all the GPU manufacturers actually buy stuff from Molex, so there goes the question: where can I buy such connectors in small quantity?They seem to be available from Mouser, Digikey and Newark, but not stocked, and minimum quantity is like 300. Farnell, RS, TME or other retailers in EU don't even have them in their catalogue. I have only found a few sketchy ones on ebay, but I'd like to think of that as a last resort.Does anyone know compatible part number from other supplier like Amphenol, TE, Tyco, Harting, Harwin, Samtec etc.?

author: Dago
author_rank: Frequent Contributor
timestamp: February 24, 2014, 12:31:06 pm
content: As far as I know these are the 6 and 8 pin (straight, not 90 degree models) PCIe power connectors (just had to buy them for a project at work last week) from Molex, plenty of stock and no minimum order:http://www.digikey.com/product-search/en?x=0&y=0&lang=en&site=us&KeyWords=WM3802-NDhttp://www.digikey.com/product-search/en?x=0&y=0&lang=en&site=us&KeyWords=WM3803-ND

author: mariush
author_rank: Super Contributor
timestamp: February 24, 2014, 01:44:29 pm
content: JMThttp://www.jmtdg.com/en_products_sub.php?k=1_74JMT2416v2-8 - 8 pin pci express (I think)WSTP#-I42002 -http://www.wst.com.tw/en/products_02c.php?list=nal&m_sn=114&sub_sn=187AMP/Tyco - VAL-U-LOK (but check keying)http://uk.farnell.com/jsp/search/browse.jsp?N=2025+204643&Ntk=gensearch&Ntt=VAL-U-LOK&Ntx=mode+matchallpartial

author: TiN
author_rank: Super Contributor
timestamp: February 24, 2014, 04:48:41 pm
content: They are mini fit Junior. Be warned, 8pin connector used in VGA cards have different key configuration! I have some if u desperate.
PCIe cellular modem recommendations? - Page 1
Forum section: electronics / projects

author: nrclark
author_rank: Newbie
timestamp: February 27, 2022, 01:20:20 am
content: I'm toying around with a potential product, and I want to add a 4G cellular modem to it. Does anybody have any recommendations for a good PCIe cellular modem module? I'm looking for something that supports 4G (or LTE or HSPA+), has a PCIe interface, and has good Linux support. My CPU's BSP is on the 5.10 LTS kernel.

author: ogden
author_rank: Super Contributor
timestamp: February 27, 2022, 01:44:01 am
content: Quote from: nrclark on February 27, 2022, 01:20:20 amWhat's the point to require PCIe interface? Get USB cellular modem instead. If out of USB ports - use PCIe USB card.

author: nrclark
author_rank: Newbie
timestamp: February 27, 2022, 02:46:32 am
content: Target device is an aarch64 SoC. USB is all booked up, but the PCIe lanes are available. I figure that I can put an M.2 cellular module on there, if I can find a good one.If you've done anything similar, module recommendations would be much appreciated!

author: KaneTW
author_rank: Frequent Contributor
timestamp: February 27, 2022, 03:07:19 am
content: Pick one of Quectel's devices. Plenty with PCIe connections.

author: fchk
author_rank: Frequent Contributor
timestamp: February 28, 2022, 07:48:30 am
content: Quote from: KaneTW on February 27, 2022, 03:07:19 amSorry, no. They might use MiniPCIe or M.2 form factor and slots. But they don't actually use the PCIe lanes. The MiniPCIe and M.2 standards also include USB 2.0 D+/D- lines, and you can even get USB 3.0 instead of PCIe (same pins).There are no modems that actually use PCIe. If you must use PCIe you will need ether an USB host controller or an high-speed PCIe UART.fchk

author: KaneTW
author_rank: Frequent Contributor
timestamp: February 28, 2022, 08:32:47 am
content: random example from the website.

author: ogden
author_rank: Super Contributor
timestamp: February 28, 2022, 04:51:52 pm
content: Quote from: fchk on February 28, 2022, 07:48:30 amSo what? OP asked for LTE or HSPA+ which is well within range of USB 2.0 throughput.
PCIE edge connector Hot plug implimentation - Page 1
Forum section: electronics / projects

author: santoshgurral
author_rank: Contributor
timestamp: May 26, 2020, 10:07:28 am
content: Hi,I want to implement hot-plug feature on my based board for PCIe raiser cards. I am referring to "PCI EXPRESS CARD ELECTROMECHANICAL SPECIFICATION, REV. 3.0" document for this feature implementation attached is the screenshot form this document.I am designing a motherboard which has x16 PCI-E slot connector on my board. I am confused so which all PRSNT2(B17,B31,B48,B81) signals should be shorted together and connect to a pull-up. I am going to insert an x16 riser card on to my motherboard x16 slot but the x16 riser card has only x8 lanes. only the physical size of the riser card is x16.As per the screenshot attached it says short all the PRSNT2(B17,B31,B48,B81)signals together and pullup to VCC. But if I shot all the PRSNT2 pins how come CPU will be able to differentiate between an x4/x9/x16 riser card.Please clarify.ThanksSantosh

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 26, 2020, 10:31:57 am
content: The interface detects active lanes, doesn't it?Tim

author: santoshgurral
author_rank: Contributor
timestamp: May 26, 2020, 01:44:47 pm
content: How does it identify the active lanes?
PCIe Gen4 Retimers:  experts needed - Page 1
Forum section: electronics / projects

author: frogblender
author_rank: Regular Contributor
timestamp: June 09, 2021, 03:28:43 am
content: Does anyone have experience with using a PCIe gen4 retimer?I gather that Intel was good enough to publish a spec for the pinout of pcie retimers, to which other manufacturers are supposed to adhere.Intel's spec is here:https://intel.ly/3zcOW8BBut Intel's spec has bga pinouts for all the pins,exceptfor the power pins (see pg. 16 in the above link, for example. For PWR_1, rail, it just says "6 pins" where the pin numbers are supposed to be).And NONE of the retimer manufacturers have datasheets with pinouts. wtf?TI#DS160PT801Astera(who?)#PT4161LRSBroadcom#PEX88T32I am in desperate need of x16 pcie gen4 retimer to slap on a boardtoday. Any help would be greatly appreciated.
PCIE reset signal fix - Page 1
Forum section: electronics / projects

author: blazini36
author_rank: Regular Contributor
timestamp: February 01, 2022, 09:21:35 pm
content: I own a couple of these small PCshttps://www.seeedstudio.com/ODYSSEY-X86J4125800-p-4915.htmlIt has 2 1gbe NICs on board. I found an issue with one of the NICs when I use an M.2 to PCIE x4 adapter. The NIC is still recognized in Linux but won't connect to anything when a PCIE card is plugged into the adapter, but the card works fine. After some back and forth with the manufacturer they found the issue as well and their response was "the reset line from the CPU can't supply enough current when the card is plugged in and it affects the NIC".I did some testing and the card NIC and card work fine when the reset line (PCIE PERST# signal) is disconnected from the adapter. Not sure if this will cause some issue, the reset line is there for a reason. Testing the line with it connected and the card plugged in I find that the reset line is pulling up to 3.3v at the card a few seconds after power on just as it should, meaning it's not being held down at the card. The way the PC is laid out I'll never find the reset line to test it at the NIC but I assume maybe they used a current limiting resistor with too high a value on the line or something.This PC is for a special project and to keep the form factor I need to make a custom M.2 to PCIE adapter PCB anyway. There's plenty of space on this PCB to do whatever. I was thinking i can use a transistor or something to work the reset line for the PCIE card. Any suggestions as to the circuit/transistor I might use. I was thinking I'd want to use a PNP BJT since the CPU is pulling up and holding the line, but I'm not the type of person who has a transistor catalog in my head.

author: blazini36
author_rank: Regular Contributor
timestamp: February 04, 2022, 03:45:20 am
content: Had to do a bit of reading up on transistor configurations, looks like a PNP-NPN darilignton pair is what I'm looking for. Since I'm not 100% sure what's wrong with the Seeed board, I don't know for certain this will fix anything but otherwise it should work.
PCIe Switch 3P/4L - PI7C9X2G304SL PERST Assertion and more... - Page 1
Forum section: electronics / projects

author: HeartOfGermany
author_rank: Newbie
timestamp: June 19, 2019, 12:37:43 am
content: Hello guys.I want to user the "PI7C9X2G304SL" as a Switch for my own add-in card. The pin PERST is described as input.Further they write and I quote: "As long as PERST# is active, all PCI Exp ress functions are held in reset. The main supplies ramp up to their specified lev els ( 3. 3 V). So met ime during this stabilization time, the REFCLK starts and stabilizes. A fter there has been time (100 ms) for the power and clock to beco me stable, PERST# is deasserted high and the PCI Exp ress functions can start up."So wait... Is all I need to do, to connect power to the IC and in 100ms drive PERST to 3.3V to enable?So basically i do the following:PRSNT1 is the last pin, that connects on the PCIe card/slot. So all I do, as soon, as this pin is connected (it drives PRSNT2 to ground) is to switch on the power voltages as described and after 100ms (the clock should be stable by now), I drive PERST to 3.3V in less than 66ns, as the PDF also tells.Is that correct? Also, is this usually done by the GPIO pins, that can be programmed? Since I have no EEPROM, to hook up and therefore no software to load to the IC, I would do it with simple, discrete transistor logic. Should this work??? It is very very hard, to find any information about PCIE.Also, there is JTAG. Well... Do I realy need JTAG? As I read it, it is used, to test the connections of the chip. But I see no requirement in doing so, right?And what about EEPROM? Is it required even? I absolutely hope not, because this project would get twice as complicated as it already is.Last but not least: What about good ol SMBus? Is it correct, to connect it to the Motherboard and the 2 Outputs in parallel? The thing is, there is no other SMBus pin. So I can only assume, that only 1 SMBus is shared between all the PCIe devices.I know these questions are hard, but please stay with me.

author: HeartOfGermany
author_rank: Newbie
timestamp: June 21, 2019, 12:03:30 pm
content: Cmone. Realy no one?
PCIe x16 MECH,  x4 ELEC:  what happens to the other 12?? Flap in breeze?  - Page 1
Forum section: electronics / projects

author: frogblender
author_rank: Regular Contributor
timestamp: April 27, 2021, 01:54:59 am
content: Once in a blue moon you'll encounter a mobo which has a physical x16 slot which is only wired x4. What does the mobo do with the remaining 12 diffpairs? Specifically: the 12 RX pairs (which are INPUT to the plugin card)... does the mobo tie these to ground or something? Or are they just flapping in the breeze? Alas, I can't find anything about this in the PCIe spec.If somebody can shed some light here, it'd be greatly appreciated.

author: Rerouter
author_rank: Super Contributor
timestamp: April 27, 2021, 02:31:21 am
content: As a number of motherboards dont even populate those pins. I would say flap in the breeze is exactly what they do.

author: Monkeh
author_rank: Super Contributor
timestamp: April 27, 2021, 02:58:49 am
content: They're AC coupled and will be biased on the receiver side. So just don't connect them.

author: technix
author_rank: Super Contributor
timestamp: April 28, 2021, 03:28:09 am
content: They will flap in the breeze, as if you have inserted the x16 card into an open-ended x4 slot and the rest of the card is literally hanging outside the socket. (Speaking of, you can cut open the plastic on the back end of the PCIe slots using a dremmel tool and make it function with longer cards, and there will be no ill effects.)On my Gigabyte Z390 UD board, those connectors only have physical pins for the x4 part. Even for my Asus Z9PE-D16 where physical pins exist on all x16 slots, those with x8 electrical connections have its back end pins going nowhere except the ground pins.

author: frogblender
author_rank: Regular Contributor
timestamp: April 28, 2021, 03:44:43 am
content: Quote from: technix on April 28, 2021, 03:28:09 amInteresting.... attached is pic of your Z390 UD... upper x12 is nothing but plastic.

author: ejeffrey
author_rank: Super Contributor
timestamp: April 28, 2021, 06:20:45 am
content: Quote from: frogblender on April 27, 2021, 01:54:59 amThis isn't once in a blue moon it is pretty common. Most if not all mainstream (not HEDT or server) motherboards with multiple x16 physical slots do this. The primary slot will have all 16 lanes wired up for single GPU use. The other slots will only have 4x or 8x lanes electrically connected.

author: technix
author_rank: Super Contributor
timestamp: April 28, 2021, 06:44:30 am
content: Quote from: ejeffrey on April 28, 2021, 06:20:45 amEven dual socket HEDT does this. My Asus Z9PE-D16 is a full blown dual Ivy Bridge server board, yet it also have a few x16 slots that is electrically x8.
PCM Manufacturer - Page 1
Forum section: electronics / projects

author: red_mamba
author_rank: Contributor
timestamp: February 22, 2011, 11:02:25 am
content: Hi!Can some one recommend a good PCB manufacturer.I need a few more quotes so I can compare prices and set the final price on the assembled PCB for a customer.Thank you!

author: scrat
author_rank: Frequent Contributor
timestamp: February 22, 2011, 12:16:29 pm
content: There are some other threads around in the forum on this topic. One is this:https://www.eevblog.com/forum/index.php?topic=1324.msg17128#msg17128Even if they speak about hobbyist, there are some professional pcb manufacturers links too.

author: red_mamba
author_rank: Contributor
timestamp: February 22, 2011, 01:14:30 pm
content: I forgot to write that I need PCB & components placed

author: metalphreak
author_rank: Frequent Contributor
timestamp: February 23, 2011, 01:31:22 am
content: http://www.goldphoenixpcb.bizThey do assembly as well. They also do all the boards for SparkFun and BatchPCB so you know they're reliable

author: red_mamba
author_rank: Contributor
timestamp: February 23, 2011, 06:15:36 am
content: sweet,I'll contact them, thank you.
PCM to I2S audio and vice versa - Page 1
Forum section: electronics / projects

author: Dajgoro
author_rank: Frequent Contributor
timestamp: May 06, 2019, 03:29:56 pm
content: HiI have some SIM (Simcom) modules(various models) with PCM audio input and output (short sync pulse mode), and on the other side I have a ESP32 module with I2S ports.I'm trying to connect the two without making it too complicated. I though about using the SPI in slave mode, but the short sync pulse can't be used as the CS signal, so that wont work.Also I don't think the transmit side clock/data polarity would be correct.All I can think about is putting in a little CPLD/FPGA to reformat the data, but that sounds as a bit of an overkill, and a MCU won't cut it since the data is too fast to bitbang.I could do it in TTL, but at that point the logic would be so complex I might as well do it with a FPGA...I found that there is a TI audio system IC in BGA, but that's too big and too complex for what I need here.Does anyone have an idea for a simpler workaround?

author: OwO
author_rank: Super Contributor
timestamp: May 06, 2019, 03:44:09 pm
content: Post a timing diagram of said "PCM audio interface"? As long as it has a clock signal at the same rate as the data then the I2S peripheral can be used.

author: Dajgoro
author_rank: Frequent Contributor
timestamp: May 07, 2019, 08:32:34 am
content: PCM:I2S:As you can see the PCM format has a frame sync pulse, then goes the data. In the case of the SIM module, it sends only one word of audio, with the rest being a long sequence of zeroes, while in I2S there is the WSL/LCK line going high and low depending on the channel selected.

author: Dajgoro
author_rank: Frequent Contributor
timestamp: May 07, 2019, 02:21:52 pm
content: Quote from: blueskull on May 07, 2019, 08:49:41 amHow?I don't have the WSL signal do frame the words/channels, besides there are 128 bits in each frame as it is now.

author: ogden
author_rank: Super Contributor
timestamp: May 07, 2019, 02:36:03 pm
content: Quote from: Dajgoro on May 06, 2019, 03:29:56 pmOne of possible workarounds: use LM49370 as PCM-I2S bridge. Appnote:http://www.ti.com/lit/an/snaa039a/snaa039a.pdfThat's *after* manufacturer confirmation that they do not offer solution for I2S audio.