hybridfree/eevblog-posts huggingface dataset:
High quality ribbon cable connectors Manufacturers  - Page 1
Forum section: electronics / projects

author: qwaarjet
author_rank: Regular Contributor
timestamp: December 09, 2015, 12:10:26 am
content: I'm designing a system that is going to have multiple boards daisy chained together via a ribbon cable. The board are going to be in an industrial environment subject to high noise, moderate vibration and the prying hands of technicians. I would like a connects that stay securely fastened, are quick and reliable to assemble. I'm planing on buying a few samples to see which ones I like best best.Does anyone have advice on good manufactures to start with or brands to avoid. Unit cost isn't a major factor since total unit count should be in the low hundreds.
High Reliability GSM/GPRS Modem - Page 1
Forum section: electronics / projects

author: RoadRunner
author_rank: Frequent Contributor
timestamp: October 30, 2013, 12:30:09 pm
content: i am currently designing a bit critical communication system, in which we have multiple mediums of communication like GSM , VHF radio. and currently i am looking for a highly reliable GSM modem to be used in this system. for now i am thinking of Moxa , visiontek , u-blox GSM modules.so my question is if you are in the position to chose a high reliability GSM modem then which would you chose? any suggestion?please helpthank you
High Resistance Rocker Switch or Alternative - Page 1
Forum section: electronics / projects

author: TinyMirrors
author_rank: Contributor
timestamp: July 29, 2019, 09:55:45 pm
content: I'm looking for a rocker switch or an alternative type of switch with a much higher than normal resistance between the terminals of the switch. I need to be near or higher than 250 mega ohms to ensure the device under test functions as expected. Currently we manually disconnect wires to and from the test device and that works fine, but would like to automate it a bit.We built a simple on off switch board which can accept a device to test. We then flip a switch or two to test some functionality. I'm working with up to 200V DC but virtually no current. The device under test is very sensitive. The issue I've come across is that there the switches we used (M2012TXW25-DA) measure 25 megaohms between the different poles of the switch. This is causing issues with testing as we can't determine if the device is faulty since a current is being measured to be too high. Say ~100 nanoamps.Measuring between pins 1 & 2 measures between 20-30 mega ohms depending on the rocker switch.1 com 2|----|----|The resistance between pins 1 and 2 of the rocker needs to be much higher. ~250 megaohms or higher.I've tested a bare pcb and I'm not able to measure the resistance between the pads the rocker is soldered to. Just in case someone was wondering.Thanks for your advice.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 29, 2019, 10:09:25 pm
content: You mean higher off-state resistance?Switches should be in the gigs, you have a bad part. Try a good name brand? Different style?Tim

author: bob91343
author_rank: Super Contributor
timestamp: July 29, 2019, 10:11:08 pm
content: I agree; those values are much too low for a good switch. Perhaps it's contaminated.

author: ConKbot
author_rank: Super Contributor
timestamp: July 31, 2019, 05:52:05 pm
content: How did you clean the switch after you soldered it? The datasheet specs 1Gohm minimum, but it also says "These devices are not process sealed. Hand clean locally using alcohol based solution."If your residue made its way inside during cleaning,that's your leakage source now. Those switches have epoxy sealed leads, so they should be fine with local cleaning with swabs, or a controlled rinse (small nozzle, keeping the solvent under the switch, not letting it coat the switch fully)

author: TinyMirrors
author_rank: Contributor
timestamp: August 14, 2019, 03:17:37 pm
content: The boards were cleaned with IPA. Though they may have been very sloppily cleaned. We've replaced them and they no longer register on the multimeter.Thanks for the help guys! I would say that cleaning them properly was the best advice that worked for us.
High-resolution video camera module - Page 1
Forum section: electronics / projects

author: Dago
author_rank: Frequent Contributor
timestamp: October 22, 2015, 11:03:08 am
content: Does anyone have any ideas on a high-resolution (video) camera module? I would like to have something that would be interfaceable to an FPGA (so parallel bus, MIPI etc. something of that sort but not for example USB). I would basically want as high of a resolution as possible and more fps the better as well. Something like 4k @ 30fps would be great, more resolution and/or fps would not hurt. Integrated or interchangeable optics are both ok. Price not terribly critical, lets say under 150€ would be ok. No strict size restrictions but nothing larger than lets say something using C-mount optics.I know very many modern smartphones for example can do 4k @ 30fps but I wasn't able to find a module with a datasheet at least yet.Any ideas?

author: Scrts
author_rank: Frequent Contributor
timestamp: October 22, 2015, 11:47:45 am
content: Do you need hardware HDR? If not, have a look into Omnivision or Aptina sensors.
High side circuit simulating strangly.. - Page 1
Forum section: electronics / projects

author: Dreamer1
author_rank: Contributor
timestamp: February 16, 2014, 08:00:55 am
content: I have designed the this high side drive, it's meant to dive a load attached to a batteryTo turn it on I just leave the charge pump on and to turn it off I turn the charge pump off and use the optocouplers to quickly drain the flying capacitor. Needless to say, I don't have must experience with this sort of things.Anyhow, when the gate of the high-side mosfet is at 12V (same as the batter and drain) for whatever reason the mosfet conducts? Why? I have attached a graph. I don't see how this is possible, the body diode is facing the other way so I don't know what it could be? Simulation error?Plus, is this a good cheap high side drive?By the way, the graph shows the voltage at the gate of the mosfet and the current through the 1 ohm resistor.Thank you for your kind help and suggestions.

author: dannyf
author_rank: Super Contributor
timestamp: February 16, 2014, 01:16:36 pm
content: QuoteBefore you get it fancy in simulation, ask yourself how does the circuit work? What is the essence of it?QuoteDoes it actually do any of that? Should it do any of that?QuoteThe mosfet would have failed if it did NOT conduct.Ask yourself under what conditions the mosfet would conduct? Are those conditions true in your circuit? ...It helps a lot if you start simple.

author: nickm
author_rank: Regular Contributor
timestamp: February 16, 2014, 03:57:19 pm
content: Your source voltage is a little under 10V so Vgs is around 2V and your FET is going linear. The problem is your opto coupler transistor is trying to pull down to 0V but you have your battery voltage pulling it up through the two diodes and the battery is winning. Put some impedance like 1kohm in between the gate and your charge pump and leave your opto transistor where it is. This way the opto transistor only has to sink about 10mA to turn the transistor off.Also you might consider using a normal transistor in an open collector configuration rather than an opto. You've probably already thought about it but you could use a P-channel FET without having to bother with the charge pump and drive the gate directly with your logic. Downside is lower RDson. Other than that I think it looks fine.

author: Richard Head
author_rank: Frequent Contributor
timestamp: February 17, 2014, 06:21:41 am
content: Circuit simulation is an amazing tool that so often is abused.99% of the time a simulator is not needed or required, just common sense.Forget the simulator and understand what you want to acheive and how it can be realised.Dick

author: dannyf
author_rank: Super Contributor
timestamp: February 17, 2014, 12:03:14 pm
content: QuoteCouldn't agree with you more.Simulation is only useful if you understand how the circuit to be simulated works AND the limitations of simulation.
High Side Current Monitor NCS213RSQT2G  - Page 1
Forum section: electronics / projects

author: maurosmartins
author_rank: Regular Contributor
timestamp: December 07, 2019, 11:12:01 pm
content: Hello all,on a small power supply I'm working, I've added an On Semiconductor NCS213RSQT2G high side current monitor as follows:if I set the power supply to 12V and draw 100mA the NCS corretly outputs 0.5V (0.1Ohms * 0.1Amps * 50V/V = 0.5V)nevertheless if I set the power supply to a different (lower voltage) and draw the same 100mA the output should still be 0.5V but it isn't and I don't understand why.I'm supplying the NCS with more or less 15V and the Vref is tied to 0V.can anyone help to shed light over this issue?looking forward your reply,Best regards, Mauro.

author: MadScientist
author_rank: Frequent Contributor
timestamp: December 08, 2019, 05:10:16 pm
content: Have you measured the voktage across the sense resistor

author: maurosmartins
author_rank: Regular Contributor
timestamp: December 08, 2019, 07:38:20 pm
content: Hello MadScientist,thank you for your reply.Yes, I've measured the voltage across the resistor and it is fine the same 10mV for 100mA.Best regards, Mauro.

author: Yansi
author_rank: Super Contributor
timestamp: December 08, 2019, 07:50:42 pm
content: As far as I can tell, I do not see a single compensation RC network, nor even a damping resistor in the output of the opamp.So, quite a good bet is it is oscillating and providing you a false reading.Have you poked the design with an osmelloscope? Verified the stability? At LEAST done a stepped load test?

author: maurosmartins
author_rank: Regular Contributor
timestamp: December 08, 2019, 08:05:11 pm
content: Hello Yansi,that might be the case, maybe the opamp is oscillating. But I don't know where the RC network / damping resistor should be.can you please provide some guidelines?Quote from: Yansi on December 08, 2019, 07:50:42 pmI have not, I hadn't reached there yet and possibly was looking at wrong causes. I'll do as you say and check the step response.Mauro.
High Side Current Sense Amplifier - Page 1
Forum section: electronics / projects

author: cinetron
author_rank: Contributor
timestamp: March 16, 2017, 08:59:56 pm
content: Wondering if anyone has recommendations for a fast high side current sense amplifier. . Currently I am using a TSC101http://www.st.com/en/amplifiers-and-comparators/tsc101.htmlbut it isn't fast enough. It doesn't seem to reliably work below about 2.5 usecs . I am looking at the LTC6101http://www.linear.com/product/LTC6101which should be faster but I would prefer a device that has a separate VCC from the source of the current to be sensed which the TSC101 offers. I want to use 5 volts to power the IC and sense current from a 24 volt supply. Ideally the amp would settle under 1 usec. I'm looking for a gain of around 20. Does anyone know offhand a good candidate for this?Thanks

author: BrianHG
author_rank: Super Contributor
timestamp: March 16, 2017, 09:07:45 pm
content: There are a few alternatives in this thread toward the bottom:https://www.eevblog.com/forum/beginners/op-amp-inputs-higher-than-rail-output-less-than-rail/

author: danadak
author_rank: Super Contributor
timestamp: March 17, 2017, 01:01:24 pm
content: This page shows some parts out in the Mhz region -http://www.ti.com/lsds/ti/amplifiers/current-sense-amplifiers/current-sense-amplifiers-products.pageRegards, Dana.

author: newbrain
author_rank: Super Contributor
timestamp: March 17, 2017, 02:24:36 pm
content: Just beware that theINAparts with 4400kHz bandwidth are actually 440kHzQuote from: danadak on March 17, 2017, 01:01:24 pm

author: cinetron
author_rank: Contributor
timestamp: March 17, 2017, 05:14:31 pm
content: Thanks for the part suggestions. I got some zetex parts based on the above suggestions and will give the TI parts a look. Thanks for the heads up on the 4400khz vz 440 khz error.

author: Siwastaja
author_rank: Super Contributor
timestamp: March 17, 2017, 05:32:35 pm
content: I like LT1999 (gains: 10,20, 50, 2MHz BW, bidirectional sensing), but if you don't need bidirectional sensing, you have more options than I did.

author: cinetron
author_rank: Contributor
timestamp: March 23, 2017, 06:50:09 am
content: Thanks for the suggestion. I have so far ended up using the Zetex ZXCT1084 which is fairly fast. Faster would be better but for the price/performance is pretty good. It appears to be working if the current sensed is on for at least 1 usec. Below that it won't work. But it seems ok for what I am doing.
High side drive - Page 1
Forum section: electronics / projects

author: Dreamer1
author_rank: Contributor
timestamp: January 17, 2014, 08:27:49 am
content: Ok, so here is my problemI have a buck-boost circuit and i'm having trouble driving the high-side mosfet. Problem is, my input range is 6V-35V. Initially we wanted to use a voltage doubler, but unfortunately at 6V input voltage would result in 12v (theoretical), and this 12V would not be enough to drive the mosfet we have picked as we want at least 10V VGS, hence 6V in, 16V - > vgs.Does anyone have any ideas how I can get around this problem? A nice chip that has an output function such asX volts in,X+10 Volts out over a large voltage range?

author: poorchava
author_rank: Super Contributor
timestamp: January 17, 2014, 09:22:20 am
content: I think all the chips use single stage bootstrap. You would need too. I guess you can make your own 2-stage multiplier and then switch it to the gate. Or you can look for mosfet with lower vth, or you can use a p - channel one.

author: Kremmen
author_rank: Super Contributor
timestamp: January 17, 2014, 02:47:06 pm
content: Or use a proper high side driver chip. Such as the IR 21xx family.

author: Pezo
author_rank: Newbie
timestamp: January 17, 2014, 04:02:24 pm
content: An IR21xx wouldn't really help, if the input voltage is 6V then so is the gate drive voltage.

author: poorchava
author_rank: Super Contributor
timestamp: January 21, 2014, 08:37:52 am
content: What are your requirements for the switch? That would really help.
High side FET drive circuit for Offline Buckboost LED driver - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: December 29, 2017, 12:12:16 pm
content: Hello,We are doing a 150W Offline Buckboost LED driver, as in the attached schematic.The high-side FET is to be driven via a digital isolator which is transferring the gate pulses up to a gate drive IC which is in the high-side circuit.The high side bias supply is also shown attached.Can you foresee problems with locating IC’s in this high-side circuit?..after all, it is referenced to the switching node.(eg noise problems and transients etc).
High-side gate driver for more than 600V? - Page 1
Forum section: electronics / projects

author: Jolle
author_rank: Contributor
timestamp: November 29, 2011, 02:46:28 pm
content: Hi there everybodyI am currently working on a SMPS project where I have to build a full bridge converter. To turn on the MOSFETs i need a high-side driver but the input voltage is about 620V and I can only find high-side drivers that can withstand 600V...?Does anybody on this forum know if it is possible to get a high-side driver that will take 620V? Then I would be really glad to know or maybe if some of you had some tips on how to use a 600V high-side driver for higher voltages it would come in handy too

author: Time
author_rank: Frequent Contributor
timestamp: November 29, 2011, 03:00:51 pm
content: http://www.irf.com/product-info/cic/fsgatedriverics.html

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: November 29, 2011, 03:16:21 pm
content: We've used those IR parts where I work and they're quite amazing. That said, you better read every IR app note with a magnifying glass. There are tricks of bypassing and issues concerning Dv/Dt that will smoke parts at a high rate until you figure them out. We thought we were pretty smart, but it still took many weeks before we understood all the component and layout pitfalls of high side switching a lot of power at 600-800+ V.

author: Jolle
author_rank: Contributor
timestamp: November 30, 2011, 07:21:49 am
content: Great, I will have a look at thoose IR drivers to see if they are usable for my circuit.Thank you

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 30, 2011, 03:23:31 pm
content: Would transformer coupling work?
High side ground and low side ground (SMPS) - Page 1
Forum section: electronics / projects

author: Yamin
author_rank: Frequent Contributor
timestamp: February 09, 2022, 05:41:34 pm
content: Hi guys,I'm designing this circuit to drive a DC brushless motor (more about this perhaps in another post) and doing some research I came across this video where he shows, how he modifies an SMPS to get 300VDC from the rectified mains and 15V from the regulated output. (for that motor it needs 300VDC, 15VDC...)He ties the high side and low side grounds together. Now as far as I know this is not such a good idea. Thoughts?There are lot of instructional posts/videos on making sure that you don't mix up which grounds you are measuring to when troubleshooting an SMPS and referencing to the wrong ground could take out your DMM. Could it take out your DMM?What are the possible ill effects of tying the two grounds together?I was hoping that you could clear this up for me. I'll include a schematic shown in that video and for him the circuit worked without anything blowing up.
High Side Load Switch Questions - Page 1
Forum section: electronics / projects

author: pacmann
author_rank: Contributor
timestamp: July 13, 2023, 08:36:30 am
content: Im looking at load switches like AP2181. Can these be used as bidirectional switches so current can flow from OUT to IN and IN to OUT as long as EN pin is enabled?What happens if a load switch EN pin is disabled and a high voltage is present on OUT pin like 20V? Spec says VOUT max is VIN+0.3 but I don't know if this applies when disabled too?Cheers!

author: ArdWar
author_rank: Frequent Contributor
timestamp: July 13, 2023, 09:00:39 am
content: Quote from: pacmann on July 13, 2023, 08:36:30 amNo. This one is reverse current blocking, so actually a load switch + ideal diode in a package.Quote from: pacmann on July 13, 2023, 08:36:30 amWell, it's not recommended...

author: pacmann
author_rank: Contributor
timestamp: July 14, 2023, 04:58:55 am
content: Quote from: ArdWar on July 13, 2023, 09:00:39 amCheers. In a similar load switch the data sheet saysQuoteI wonder if that is the same for the AP2181 too?
High side mains voltage current measurement using a shunt resistor - Page 1
Forum section: electronics / projects

author: Entropia
author_rank: Regular Contributor
timestamp: October 27, 2022, 06:54:10 pm
content: Hi guys.Searched around a bit but did not find an exact match for my question.My problem: measure small (5 to 500 mA) AC currents at 230 VAC RMS levels accurately. Due to size constraints using a current transformer is not possible, and Hall effect sensors are not accurate enough. I've decided to use a shunt resistor. Also I must measure from the high side since return currents are out of my scope (will be returned elsewhere).I'm having some trouble understanding if I'm able to do this using some regular current sense amplifiers if I'm using an isolated power supply for my measurement circuit. I've drawn this schematic for illustrative purposes. 230 VAC labels refer to phase. Neutral or earth is not concerned.Please do not mind the missing bypass caps etc., this is just for illustrative purposes. My idea is to supply the INA250 from an isolated DC-DC converter as well as a microcontroller which samples the output voltage from INA250. Microcontroller will then send its measurements over a digital isolator to rest of the circuit.The question is: will the INA250 mind if it's used like this? I.e. will I exceed its specifications? As far as I understand, passing 500 mA through its internal current shunt resistor (2 milli-ohms) will produce differential voltage of +/- 1 millivolt. Maximum allowed differential voltage is +/- 40 V and maximum allowed common mode voltage is GND -0.3 to 40 V. Common mode is the bit I'm confused about...Any help?

author: jonpaul
author_rank: Super Contributor
timestamp: October 27, 2022, 08:07:17 pm
content: accuracy résolution harmonics PF required?Insument amp plus Iso PS plus digital, super costly complex, bound to fail on CM transientsSmall sized current transformers are easily accessible from Coilcraft etcIsowatt makes small Hall effect isolated current sensorsjon

author: jbb
author_rank: Super Contributor
timestamp: October 27, 2022, 08:14:58 pm
content: Analog Devices make single phase power metering chips which are intended for shunt resistors and wide current range. They do A RMS, V RMS, true power and others. Interface is usually SPI so you could use a digital isolator chip to get this measurements out.

author: moffy
author_rank: Super Contributor
timestamp: October 27, 2022, 11:19:03 pm
content: The HCPL-7520 is a fairly cost effective opto isolation amp meant for current measurement. It's in stock at Digikey and Element14 and is quite simple to use.https://docs.broadcom.com/doc/AV02-0956EN

author: Entropia
author_rank: Regular Contributor
timestamp: October 28, 2022, 06:43:26 pm
content: Thanks for all the input so far.So one thing I didn't mention before is that I need twelve of these current measurements (plus one for voltage) on my board and a 5 USD current transformer or opto isolation amp adds up quite fast... I will look into the suggested options.If you guys have any more, I would be very grateful for any and all suggestions.
High side mosfet switch and High voltage H Bridge motor driver - Page 1
Forum section: electronics / projects

author: singhpk99
author_rank: Newbie
timestamp: July 03, 2013, 12:45:45 pm
content: Dave,This seems like a good idea for your fundamentals friday.High side Mosfet switch as used in numerous power suppliese.g. Simple switcher series from NS/TI lm2676 etcand the hv drivers like IR2110 used for driving the gates of washing machine motor mosfet h-bridge circuits.A good example would be a LM311 based hysterectic downconverter switching power supply .
high-side n-channel mosfet driver (DRV8711) randomly dies - Page 1
Forum section: electronics / projects

author: ikcalB
author_rank: Newbie
timestamp: March 18, 2016, 11:26:22 am
content: Hi guys,while building a stepper controller, we seem to get random defects on our high-side N-channel MOSFET drivers.My collegue designed the controller based on a Texas Instruments DRV8711..(this IC is basically a double H-bridge driver and also takes care of current regulation)On the eval-board, as well as on our prototype run from a lab power supply, we did notexperience hardware defects. (we're going back to that setup, and try testing more thoroughly with that)ATM we're on a test-setup, which is like the final control in the machine and get random defects on the DRV8711:Sometimes while running, sometimes when just applying power to the motor - that IC dies.Most of the time we only have shorts from high-side driver / chargepump / internal voltage regulators to ground,once and then we get physical damage: the case spalls away around pin4 (which is power supply).See the schematic and the most relevant datasheets attached, here is a link to our discussion on the TI forum:http://e2e.ti.com/support/applications/motor_drivers/f/38/t/498750DRV8711 product page:http://www.ti.com/product/DRV8711This project is under pressure - any help greatly appreciated, guys!Thank you very much & best regards from AUSTRIA,Florian
high side n channel mosfet  - Page 1
Forum section: electronics / projects

author: vini_i
author_rank: Regular Contributor
timestamp: May 01, 2015, 02:28:05 am
content: what is the advantage or disadvantage to using a high side n channel mosfet versus a high side p channel mosfet?i'm working to make some changes to a small motor drive board. the only function of the board is to turn a small set of 3.3v motors on and off. the circuit i fully isolated from everything and is controlled using a opto isolator. the basic topology is; 24v is stepped down to 3.3v. then there are some filter and stiffening capacitors. then there is the n channel mosfet and then the out put to the motors. the mosfet is driven with a ltc1981 driver chip. the driver is pulled up and the opto pull it down.if i was designing this circuit i would have used a p channel mosfet. the original designer is no longer around to ask. am i missing something? why would the original designer have used an n channel?

author: BradC
author_rank: Super Contributor
timestamp: May 01, 2015, 02:32:17 am
content: Quote from: vini_i on May 01, 2015, 02:28:05 amLower Rdson, cheaper, greater selection.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 01, 2015, 07:02:04 am
content: Quote from: BradC on May 01, 2015, 02:32:17 amthats the pro. the con is you need the bootstrapper like the ltc1981.... p-mosfet is vice versa that.

author: Jeroen3
author_rank: Super Contributor
timestamp: May 01, 2015, 08:15:24 am
content: p-channels are somewhat more difficult to produce. And therefore more expensive.Using an N-channel only requires a voltage booster, these are available in small IC's nowadays, so the threshold of getting high-side N switches is not as high.You can even get smart high side switches (or powerpath controllers if <5V), which are basically n-channel and driver circuitry integrated. Infineon has as lot of these. They're nice because some have feedback circuitry and automotive specifications. Bit more expensive though. But nice as low current solid state relays.Compare some n-channel with high-side driver combo's, versus p-channel fets. And see what suits the design best. Probably p-channel in your case. If you're not running a lot of amps.
High Side PFET bidirectional switches not working?? - Page 1
Forum section: electronics / projects

author: ridgerunnersjw
author_rank: Contributor
timestamp: December 15, 2023, 02:12:11 am
content: Hello.I have the following circuit that I built up on the bench and tested in ltspice. It seems that the powering of the input power to the circuit is enough to turn the two PFETs on independent of the NFET. If I disconnect the 1Meg resistor from the gates the circuit will power up and supply load power without at the moment I connect the 60V power switch. Can someone please tell me how to solve this? Is it a leakage current issue?Thanks

author: moffy
author_rank: Super Contributor
timestamp: December 15, 2023, 03:46:02 am
content: Try putting a 1M resistor in parallel with D1/C1 while having R1 disconnected and see what happens.

author: ridgerunnersjw
author_rank: Contributor
timestamp: December 15, 2023, 03:22:27 pm
content: Although I don't see the logic with this I did try it. It made no difference. Removed R1 and placing a 1M in parallel Source to Gate the powering of the 60V triggers the devices to turn on.

author: shapirus
author_rank: Super Contributor
timestamp: December 15, 2023, 03:41:08 pm
content: .doc, really? Not even a pdf, not even a docx or odt, but .doc?Come on, attach a picture. Chances of getting help and hints are higher when people don't have to run external programs (that they may not even have installed) to open your files.

author: Peabody
author_rank: Super Contributor
timestamp: December 15, 2023, 04:14:44 pm
content: But it does turn back off doesn't it? Or does any power getting to the load automatically power up V2?You might try switching the positions of the two mosfets so that the drains are connected together, then move the pullup resistor, the zener and the capacitor over to the 60V side. Also try a much smaller (ceramic) capacitor.Assuming V2 is not coming up too, I think the basic problem is that when 60V is initially applied, the source rises faster than the gate, so for a while the mosfet is turned on. But it's not clear why that is happening. In theory, the 60V should pass through the left mosfet's body diode, through the capacitor to the gate, so the gate should also rise. But maybe switching things around as described above will make it work.A separate question is why you are using two mosfets back-to-back. In what sense does the circuit need to operate in a "bidirectional" manner? Does current ever flow from the load back through to the 60V side?
High side power switch with P-channel MOSFET - Page 1
Forum section: electronics / projects

author: Wilson__
author_rank: Frequent Contributor
timestamp: July 11, 2024, 01:27:16 pm
content: Is this circuit correct?It switches on Li cell 4.2V to resistor voltage divider that feeds ADC to read cell voltage state of charge.Switch off after ADC measurement to avoid constant draining of Li cell.Many thanks

author: ajb
author_rank: Super Contributor
timestamp: July 11, 2024, 02:30:31 pm
content: Yeah, that looks fine. I wouldn't really call it a "power" switch, since even though it's switching a power supply connection it isn't really powering a load in the usual sense. It's just a signal switch in this case. But if it were a higher power application, R2 requires some consideration -- at 100k it will result in a fairly slow turn-off of M2, which could be problematic. For switching a voltage divider, though, it's perfectly fine.

author: Peabody
author_rank: Super Contributor
timestamp: July 11, 2024, 03:01:59 pm
content: Excuse the hand drawing, but below is a somewhat simpler circuit. It works even if D4 is at a lower voltage than the battery. It basically replaces the NMOS with a capacitor.

author: Wilson__
author_rank: Frequent Contributor
timestamp: July 11, 2024, 11:00:52 pm
content: Many thanks.Yes, the resistor determines speed of (dis)charge of gate. We did not read that part of data sheet before, any headup on how these are specified?Many thanks
High Side Switching N Channel Mosfet - Page 1
Forum section: electronics / projects

author: Etesla
author_rank: Regular Contributor
timestamp: July 22, 2018, 02:20:08 am
content: I am trying to better understand high side switching with N channel mosfets using discrete components. The problem I am running into is as follows: In what I understand to be the standard bootstrap configuration like in the picture below, the voltage from the gate to the source of the power mosfet is always about equal to the supply voltage. If I am trying to use a supply voltage higher than what the mosfets gate to source rating can handle, like above 20V ish, I blow up the fet... My initial thoughts are to use a zener to drop the voltage after R1, or to add a smaller resistor from R1 to ground to act as a voltage divider. I feel like both of these solutions are pretty crap simply because of the power losses associated with them and the large components they would require to work out... Im not willing to accept using a higher value resistor for R1 because I want to still be able to switch at high speeds, preferably above 40khz or so eventually. I am also trying to avoid the addition of another isolated power supply, as I would like everything to have a common ground... Gate drive transformers are also out of the question. Anybody know how this is done without IC's in real life? Thanks!

author: duak
author_rank: Super Contributor
timestamp: July 22, 2018, 03:34:12 am
content: Where to start.As you've found, Vgs max for M1 is about +/- 20 V max. A 15 V Zener diode with the cathode on M1's gate and anode on M1's source will protect M1 from excessive Vgs.Look at the reverse breakdown voltage for D1. I think it's like 35 V or so.This circuit has a few other problems and is probably not practical as it sits. The FETs can be easily damaged with an improper load. Without a floating gate power supply, the output voltage will be a few volts below the power supply voltage.ICs bootstrap the high side drive with diodes and capacitors and will have a maximum cycle time requirement. ie., they can't maintain the high on state indefinitely. I think some of the early app notes for the IR 21xx FET drivers show a simplified diagram.Cheers,

author: EmmanuelFaure
author_rank: Regular Contributor
timestamp: July 22, 2018, 10:42:09 am
content: For high frequency/non-DC signal the simplest and cheapest way is this one. It's not suited for DC or low frequency operation because of the capacitor discharge and gate/diode leakage currents. With 1nA leakage and a 1µF capacitor, drift = 1mV/second. The input PWM signal provides the energy to charge/discharge the gate. At startup, it takes some time for C1 to charge (Here < 1 milisecond), but it's perfectly fine in most cases.If the supply voltage increases significantly it takes some time for C1 to charge again. If the supply voltage decreases significantly D2 is here to protect the gate against breakdown.If you want to keep your schematic, the capacitor voltage limitation with a zener is the way to go.
High speed ADC driver component selection - Page 1
Forum section: electronics / projects

author: xzswq21
author_rank: Frequent Contributor
timestamp: December 27, 2017, 06:44:45 am
content: HelloI have a active ADC driver using a Fully differential amplifier (FDA) in my circuit.the ADC is 125MSPS 14Bit.I have found some companies have used two 50 Ohm %1 RF resistors after the FDA. usually the price of each resistor is $2.5but I have chosen 49.9 Ohm 0.1% 0603 ERA3A series from Panasonic resistors for this purpose.Do you see any problem?Thanks
High speed connectors and cables - Page 1
Forum section: electronics / projects

author: DroneBuster
author_rank: Contributor
timestamp: November 30, 2016, 08:17:19 pm
content: Hello,Currently I'm designing FLIR Tau 2 brakeout board. I'm planing to use LVDS signals (70-140Mhz) coming from camera, but I'm stuck with connector and cable selection. Best would be to use flat flex cable, but I'm struggling to find affordable and widely available solution.I have looked into KEL Co. USL series (as they are used on Sony block cameras), but I can't find them in small quantities. Manufacturer minimum order is 100pcs for connectors (1 euro each) and 18 euros per cable (didn't specify min. q. but they have 74 in stock currently). This seem a bit pricey for few boards we are going to make. Does anyone have suggestions for connectors and cables?Maybe I should stick with standard 0.5mm ffc and hope it works...
High speed design - Page 1
Forum section: electronics / projects

author: georgeg
author_rank: Newbie
timestamp: June 20, 2012, 04:10:42 pm
content: What are high speed back plane and mid plane design? Why are high speed designs more popular nowadays?

author: T4P
author_rank: Super Contributor
timestamp: June 20, 2012, 04:15:07 pm
content: Quote from: georgeg on June 20, 2012, 04:10:42 pmDuh. What is the world now without high speed? USB? SATA3?

author: Time
author_rank: Frequent Contributor
timestamp: June 20, 2012, 05:39:43 pm
content: because faster is better.

author: typeglob
author_rank: Contributor
timestamp: June 20, 2012, 08:38:21 pm
content: Quote from: Time on June 20, 2012, 05:39:43 pm... and faster is often cheaper than more at a lower speed. They'll run links in parallel again once they've saturated the bandwidth.

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 21, 2012, 06:25:13 am
content: there will be always room for improvement... USB10,1THz1TBps speed 8bit bus... USB201PHz1PBps, 32bit bus.

author: amspire
author_rank: Super Contributor
timestamp: June 21, 2012, 06:57:29 am
content: Quote from: typeglob on June 20, 2012, 08:38:21 pmThey will not go back to parallel when they cannot get any more serial speed. They may run multiple serial links - each independent.

author: ejeffrey
author_rank: Super Contributor
timestamp: June 21, 2012, 07:34:51 am
content: In fact they already do. PCI express x1 is a single (bidirectional) serial link. x4 and x16 are multi-lane serial links, but it isn't correct to say that it is a 4- or 16- bit parallel link. The channels are largely independent at the electrical level (each channel generates its own recovered clock) and the controller stripes data byte-by-byte (not bit-by-bit) over the active channels.Parallel buses are still the king for extremely high bandwidth, low latency, close range connections like on-chip data bus, a memory bus, or a ADC connection, but as soon as you want to transmit more than a few cm, it is time to serialize (if you want high speed).
High speed differential connectors  - Page 1
Forum section: electronics / projects

author: qwaarjet
author_rank: Regular Contributor
timestamp: May 07, 2014, 12:30:21 am
content: I have project that requires me to pass a 200mhz differential signal through a bulkhead (HOTLink II). The nominal impedance for the diff pair is 100 ohms and will need to travel ~3m. I have complete control over termination style and cable type; I was thinking either a rj45 cat7 bulked or possibly two 50ohm RF connectors like sma or similar and use 1 for each side of the diff signal. I would like to keep the cost relatively low <$100 ( connectors and cable) so twinax was out. Any better suggestions or just go with cat7?

author: Stonent
author_rank: Super Contributor
timestamp: May 07, 2014, 06:23:35 am
content: CAT 7 seems overkill since CAT 5e is rated to 350MHz, unless there's some other characteristic in CAT 7 that you're needing.

author: Dago
author_rank: Frequent Contributor
timestamp: May 07, 2014, 10:29:36 am
content: Quote from: Stonent on May 07, 2014, 06:23:35 amIf the frequency of the differential signal is 200 MHz then it contains frequency components way way higher than 200 MHz, since it is not a sine wave.

author: fcb
author_rank: Super Contributor
timestamp: May 07, 2014, 11:11:40 am
content: Hotlink - there's a blast from the past.I would look at CAT5 and upwards. 3M isn't that far - test it. Also, you could consider USB3 connectors and cables, just use the D+/D- lines.

author: ejeffrey
author_rank: Super Contributor
timestamp: May 07, 2014, 11:37:15 pm
content: Cat5e is only rated to 100 MHz, and used with signaling rates of 125 MS/s in fast and gigabit ethernet. For a 3 meter run it will probably work fine at 200 MHz -- the loss is just too high for long runs like ethernet is expected to work over (typically 100 meters). Cat 6 works for 250 MHz, Cat6a is rated for up to 500 MHz. Cat 5 and 6 are normally unshielded, but also available shielded. Cat 6a is always shielded.

author: miguelvp
author_rank: Super Contributor
timestamp: May 08, 2014, 03:08:07 am
content: Just 3 meters? You probably can re-purpose an hdmi shielded twisted pair (100 Ohm).A network cable (even Cat 5 shielded) might do, after all 1000 Base T only requires Cat 5 for pretty long lengths so 3 meters should be fine too since it's rated for 100 meters, and it's 100 Ohm rated as well.

author: David Hess
author_rank: Super Contributor
timestamp: May 09, 2014, 09:12:13 pm
content: Just to keep in mind how well balanced transmissions line works, here is a photo from inside of a Tektronix 100 MHz oscilloscope showing a pair of 100 MHz differential transmission lines. Normally the wires are attached inside the connectors but I had to resolder them.
High speed discrete ring counter - Page 1
Forum section: electronics / projects

author: matseng
author_rank: Frequent Contributor
timestamp: February 24, 2016, 02:54:36 am
content: I'm toying a bit with the idea of making a the beginnings of a low-res video card(s) using discrete parts and no ICs.Instead of spending a lot of transistors making gates to build binary counters for the line/row pixel address generators and then spend an almost equal amount of transistors/gates to decode the binary addressed into select signals for each individual memory location I realized that I could just as well just use two ring counters, one for the rows and one for the lines.If going by Chip-8 resolution for the video I need one 64-step and one 32-step counter. The 32-step unit would step rather slowly since each pixel would comprise 8 lines - so only about 4 KHz. But the 64-stepper needs to be stepped in roughly 3 MHz which is quite a bit too high for the common variants of simple capacitively coupled bjt/scr-based ring counters like this one:Any ideas of a suitable architecture for a higher speed design? Luckily I just need it to work in an narrow frequency band and not at DC to 3MHz, that will probably make it a bit easier.Maybe I can find some schematics in some 60'ies frequency counter and adapt it to use parts available today...
High Speed PCB Layout: USB 3.0 Tracks On Top Layer or Stripline inc Vias?? - Page 1
Forum section: electronics / projects

author: Chendy
author_rank: Contributor
timestamp: July 18, 2024, 03:10:47 pm
content: Hello,I'm new to high-speed layout. Have been doing my best to learn.What's the general recommendation when routing say a USB 3.0 signal between two SMD pads?A) Route signal on the top layer, so no via transitions. But is microstrip so only shielded from below.- I guess, this has better signal integrity but worse EMI/EMC susceptibility.B) Route signal on an internal layer, 2x via transitions. But now stripline, so the signal is shielded by ground planes above and below.- I guess this has worse signal integrity, but better EMI/EMC susceptibilityI have a network-router-type project.I'm unsure what option would be better? Generally or perhaps for my use case.I don't think we would have any unusual noise sources, this is a general consumer product.Thanks : )

author: eb4fbz
author_rank: Regular Contributor
timestamp: July 18, 2024, 04:23:15 pm
content: I guess it depends on the required trace length. I would not bother going stripline for 10mm, but probably yes for >50mm.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 19, 2024, 03:26:19 am
content: Worse with respect to what?Microstrip with full-board ground plane is generally sufficient for commercial EMC levels. Do you have more stringent levels to meet? A tight layout e.g. putting lines too close to the edge, or near slots, unrelated traces?Tim

author: Chendy
author_rank: Contributor
timestamp: August 07, 2024, 01:20:33 pm
content: @T3sl4co1l"Worse with respect to what?"Not sure, all things included I guess? Wanted to understand the general balance for my general use case as described.Your answer is pretty much the sort of guidance I was looking for... No its a lowish density board without any special considerations@eb4fbzThanks, helpful

author: jonpaul
author_rank: Super Contributor
timestamp: August 07, 2024, 08:05:49 pm
content: See Howard Johnsons excellent sitehttps://highspeeddigitaldesign.com/hj.htmlHigh Speed Digital Design: A Handbook of Black Magicby Howard Johnsonhttps://www.amazon.com/High-Speed-Digital-Design-Handbook/dp/0133957241Enjoy and Bon Chance! 'JonJon
High Speed SD Layout - Page 1
Forum section: electronics / projects

author: Rerouter
author_rank: Super Contributor
timestamp: May 26, 2017, 10:42:35 am
content: I'm currently a bit confused reading around on the SD card specifications,To set the scene i am using SAM3X8E, and connecting to a microSD card slot, I plan to connect to it using the 4 bit SDIO peripheral at 48MHz.On this micro they put SDAT0 all the way on the opposite side of the chip to the rest of them, meaning it ends up being a very long trace compared to the rest of the connectionsIt is a 4 layer PCB, with SDAT0 jumping to the other side for 3mm, both planes in this area are ground planes.Now while this chip doesn't give any info on it, a few microchip datasheets imply SDAT[0-3] should be within 250 mils (37ps) of one another, and be at most 1500 mils (220ps) longer than the clock,Others mention no real limitation but say the traces must match 50 ohm within a few %.And then on the far end we have sd.png which is from the SD standard, which implies atleast to me that within 3ns is ok,So which one do i trust, sd1.png is running slightly thinner traces with an impedance close to 65 ohms, but meets microchips requirements (they made note to run grounds between to reduce cross talk but i doubt its required), while sd2.png is 50 ohm +- 7% but no length matching.in SD2.png, CLOCK is 13.6mm, COMMAND is 14.3mm, DAT0 is 34.5mm, DAT1 is 34.5mm, DAT2 is 21.2mm, DAT3 is 20.1mm.in SD1.png, CLOCK is 13.6mm, COMMAND is 14.5mm, and all DAT's are 34.5mm exactly.

author: amyk
author_rank: Super Contributor
timestamp: May 26, 2017, 11:37:52 am
content: The data window will be shifted slightly; you'll have to do the timing calculations to figure out if it is acceptable (my guess is that it probably is) --- and the fact that one pin is on the other side, doesn't preclude the others having to travel slightly longer on the die itself.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 26, 2017, 12:23:14 pm
content: The timing diagram says you have at least +/- 3ns or about +/- 0.6m. It's not going to care.If you have only one SD card, then source termination resistors should be used, very near the driving pin for that trace (if bidirectional, then one on each end). The total resistance should match the PCB trace impedance.Total resistance includes pin driver impedance, which is usually around 30 ohms for a CMOS logic pin, so for a 100 ohm PCB trace, 70 ohms is enough resistance. 47 ohm resistors are very commonly used. It's not very critical unless the length is comparable to the rise time.Tim
High speed trace impedance questions  - Page 1
Forum section: electronics / projects

author: Sniper1
author_rank: Regular Contributor
timestamp: March 03, 2023, 08:33:11 pm
content: So i am doing one of my first boards that uses I2S and i saw that one clock signal can go up to 50MHz and that got me a bit worried.The datasheet mentions 22-27ohm series resistors so i added them. I also read somewhere that the line impedance should be as close as i an do 50 ohms.Same for 4bit SD interface.BUT then wont the resistor mess up the impedance?50MHz is not the fastest out there but should I bother with rounded edges?Yes i know i need a unbroken GND plane under and to keep them as short as i can +transfer vias.But is the any other thing that i need to keep in mind?Also if i were to pur some test point on these lines should i put them on the lines themselves or go off to the side and put them there? ( i was thinking of going down to the bottom layer and putting the test pads there . I think i am safe from reflections but better ask now then be sorry in my a mouth.

author: TimFox
author_rank: Super Contributor
timestamp: March 03, 2023, 08:38:55 pm
content: Google for "source termination" for full discussion, e.g.https://practicalee.com/termination/A common method to drive a transmission line into a high load impedance without losing voltage.The positive reflection at the high-Z load restores the full amplitude of the pulse, and the source termination (series resistor plus driver output resistance) absorbs the reflection.[ed: fixed typo]

author: Benta
author_rank: Super Contributor
timestamp: March 03, 2023, 08:50:03 pm
content: Here you go:https://www.tiffe.de/robotron/Bausteinuebersicht/MECL/HB205-D.pdfChapters 3 and 7.Cheers.

author: Sniper1
author_rank: Regular Contributor
timestamp: March 04, 2023, 09:14:06 am
content: THX for all, now time to read and apply it.

author: jonpaul
author_rank: Super Contributor
timestamp: March 04, 2023, 09:56:42 am
content: Dr Howard JohnsonHigh speed Digital Design

author: iMo
author_rank: Super Contributor
timestamp: March 04, 2023, 10:11:07 am
content: You do not need to mess with transmission lines on the pcb provided your signals are around 50MHz (btw the "edges steepness" of the signal determine the BW, not the clock frequency itself), and not longer than 10-15cm.Simply do your tracks as you need and put those 22ohm resistor in series (those resistors dump the ringing).Btw the width of a trace for 50ohm transmission line above gnd plane on the FR4 material pcb 1.5mm thick is something like 3mm, afaik..

author: Sniper1
author_rank: Regular Contributor
timestamp: March 04, 2023, 05:01:39 pm
content: Quote from: imo on March 04, 2023, 10:11:07 amokBTW for my 4 layer design that is .2933 mm and that is a bit smaller then my ESP32 pads so fine i guess