hybridfree/eevblog-posts huggingface dataset:
Minimum bend radius of addressable LED strips? (along the natural bend axis) - Page 1
Forum section: electronics / projects

author: chconnor
author_rank: Contributor
timestamp: November 16, 2022, 11:24:25 pm
content: So I'm consulting for some folks and trying to come up with RGB LED lighting with color/intensity controlled by an MCU. This lighting will need to fit into a tube, roughly .5 to 1" in diameter (1.3-2.5cm), and radiate in all directions perpendicular to the tube axis. (Tube is also only 1-2 inches long.)Additionally, I would love to avoid external circuitry/soldering for the sake of rapid assembly.So I thought to use addressable strip LED lighting coiled up in the tube. I don't actually need individual LED control, but the ease of hooking it up to the MCU (and possibly sharing a PSU) made it seem like a good choice.But I can't get a clear answer on how tightly you can bend this stuff... I get the impression that .5 or even 1 inch radius is too tight. Some manufacturers state much larger minimum radii but I see videos of people bending them much tighter... There are a million pages/videos about bending it along the flat axis (aka "the hard way") but I'm curious about the way it naturally bends and nobody seems to care about that. :-)(I thought of wiring four or five cut-down pieces in parallel (maybe they could even share a data line?), so they wouldn't have to be bent at all, but that's getting a bit complicated in terms of assembly.)Or maybe I can find an addressable RGB lamp instead? I find non-addressable single-colorlamps like this... form factor is good but I want addressable RGB...Thanks for any pointers!

author: artag
author_rank: Super Contributor
timestamp: November 17, 2022, 10:47:40 am
content: Any repeated bends are bad. If you just do it once, it's a lot more tolerant.Bending between leds can be fairly tight - maybe 2mm radius. But don't do that near the leds - if you make a bend that includes a led it probably does need to be 20-30mm or the solder joints will tear away from the copper. If it's very dense strip (144 led/m) it will be difficult to bend between leds.

author: chconnor
author_rank: Contributor
timestamp: November 17, 2022, 05:33:53 pm
content: Thanks a lot -- that aligns with what I have started to figure out as well, so it's nice to hear that I'm on the right track. I'll get a strip or three and see what I can get away with.
Minimum contact current; reed relay - Page 1
Forum section: electronics / projects

author: GK
author_rank: Super Contributor
timestamp: December 05, 2012, 03:29:10 am
content: Does anyone know much about the internal construction and minimum reliable switching current of D.I.L. reed relays such as these:http://www.farnell.com/datasheets/16797.pdfThere is no spec. for minimum switching current, but the datasheet does say “hermetically sealed switching contact is immune to the effects of its environment”.Can I therefore safely assume that the contacts are vacuum-encapsulated in a glass envelope or something and thus immune to oxidation effects?I’m considering using these for input attenuator switching for a 10M-Zin DVM. Contact current will range from fA to nA.

author: EEVblog
author_rank: Unknown
timestamp: December 05, 2012, 04:17:24 am
content: Quote from: GK on December 05, 2012, 03:29:10 amYes, they usually are.QuoteCheck out Pickering, they make some of the best signal level reed relays, like these low-emf ones:http://www.pickeringrelays.com/pdfs/100.pdfDave.

author: SeanB
author_rank: Super Contributor
timestamp: December 05, 2012, 04:27:19 am
content: Correct, as long as you have never used them to switch high current they will reliable switch down to single electron currents. Best for low current are gold plated or mercury wetted ones, as they have the lowest contact resistance variation.

author: GK
author_rank: Super Contributor
timestamp: December 05, 2012, 05:31:36 am
content: OK, great, thanks. I don’t need anything fancy, contact resistance wise. In a 10M attenuator 0.1 or 0.2 ohms contact resistance doesn’t amount to much. I’ll compare the price and availability of the Pickering units.

author: SeanB
author_rank: Super Contributor
timestamp: December 05, 2012, 03:42:52 pm
content: The gold flashed units also have the best repeatability other than the mercury wetted ones.

author: ElectronicTonic
author_rank: Contributor
timestamp: December 05, 2012, 04:06:48 pm
content: Of interest here may a video featured on Amp Hour #88.It's amazing how much precision engineering goes into making these reed switches.

author: SeanB
author_rank: Super Contributor
timestamp: December 05, 2012, 06:29:47 pm
content: If you are switching low level signals you want relays with a low coil to contact capacitance, along with a shielded reed, so that you do not get noise from switching imposed on the signal of interest. If you are packing them in a high density you also want a shielded housing to keep interaction to a minimum.
minimum track width for 70um boards - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: August 18, 2010, 08:07:20 pm
content: I'm thinking of making something with 70 um copper (2oz/sqft), will I be ok using 0.64mm traces ?

author: DJPhil
author_rank: Frequent Contributor
timestamp: August 18, 2010, 08:32:28 pm
content: I had to do the math on that one. I believe 25mil (0.64mm) should be fine, but it really depends on your etching process. Many board houses will go down to half that, but they've got the good equipment to guarantee it works.I just did a 1oz board with a 15mil (0.381mm) border and it came out ok even with my crappy etching skills. I had a bit of undercut in spots, mainly because I'm really sloppy with the FeCl + sponge method. I haven't finished it up yet but it looks like it'll hold up fine, and I can always coat it if I get worried.Hope that helps.

author: Simon
author_rank: Unknown
timestamp: August 18, 2010, 08:37:10 pm
content: well if I ever made it in number I would probably use a board maker and might get away with 35 um copper on prototypes although I could give 70 um a go

author: djsb
author_rank: Super Contributor
timestamp: August 18, 2010, 09:48:51 pm
content: Are you using the thinner copper because it's cheaper or for some other reason?David.P.S DOH! Should've asked what the standard weight was before asking and read the OP message properly. Thats what you get when posting when youre tired.

author: RayJones
author_rank: Frequent Contributor
timestamp: August 18, 2010, 11:14:35 pm
content: isn't 2oz thicker than the usual 1oz?Going by recent discussions with Simon, I'd say he's planning on monitoring significant currents, hence the thicker copper, hence more concern about undercutting.

author: EEVblog
author_rank: Unknown
timestamp: August 19, 2010, 02:04:19 am
content: 25 thou is massive, no problems at all.Dave.

author: Simon
author_rank: Unknown
timestamp: August 19, 2010, 06:32:45 am
content: Quote from: RayJones on August 18, 2010, 11:14:35 pmcorrect, standard boards are 35 um (1 oz) as I'm passing 20+amps I thought 70 um would be advisable but do have SOIC/SMD parts with 0.64mm tracks, also going into a car environment I think toughest is best.Yes I've heard undercutting is an issue with thick copper but did not know at what widths it becomes critical
MiniSAS to U.2 pinout? - Page 1
Forum section: electronics / projects

author: Marsupilami
author_rank: Frequent Contributor
timestamp: June 03, 2023, 06:57:24 am
content: Guys,Help me untangle this, I'm missing something.I boughtone of thesePCIe MiniSAS HD (SFF-8643) cards.There is no mention of it having to use any specific type of cable, so I assumed there is a standard for it.I'm looking at theSFF-9402 Multi-Protocol Internal Cables for SAS and/or PCIespec that I would think should cover this. It has a bunch of tables showing what goes where in cable assemblies with various connector combinations.The problem is that on my board other than the PCIe TX RX pairs everything is going to a totally different pin.Let's assume I want to run this thing with it:https://a.co/d/beukd9JWhich document describes the signal pinout for that use case?Does anyone of you have experience with these standards? Am I looking at the wrong doc or... ?Edit:The MiniSAS HD-MiniSAS HD (SFF-8643) cable I have seems to follow the signal crossing rules in the SFF-9402 standard.However on the PCIe card other than the PERxN/PETxN pairs there is total mixup. For e.g. The PCIe refclock +- goes to A1 and A2 instead of C1 D1 as the doc suggests.
Miniscule springs - Page 1
Forum section: electronics / projects

author: steve30
author_rank: Frequent Contributor
timestamp: September 29, 2013, 07:47:39 pm
content: Its annoying when working on something with small delicate mechanical parts and you loose them.Yesterday I had a tiny spring spring across to another location and now I can't find it. It was probably about 0.5mm wide by about 2mm long.Does anyone have any ideas for replacing things like this. I'm not really sure where to find tiny parts like this. My device will work OK without it, but it does mean that my mode knob no longer has any clickyness.

author: Astroplio
author_rank: Regular Contributor
timestamp: September 29, 2013, 08:23:06 pm
content: I have seen a spring this small in a DIP switch, perhaps you have something like that in your misc part bin?Hope you will find something!George

author: rollatorwieltje
author_rank: Unknown
timestamp: September 29, 2013, 08:45:01 pm
content: Look for old cellphones, they sometimes use tiny springs as contacts for the speaker.It may be worth looking on DealExtreme for cellphone parts, likethis.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: September 29, 2013, 09:27:21 pm
content: They aren't hard to wind if you have some fine piano wire. As above, the next best thing is to find something that has a similar spring.

author: steve30
author_rank: Frequent Contributor
timestamp: September 29, 2013, 11:57:10 pm
content: ThanksI'll have a look in the junk box as I think I have some spare springy switches somewhere.
MinLeaf NPS3010W NPS605W Ripple And Noise FIX explain modification - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: February 13, 2021, 12:43:08 pm
content: this video explain it all (i hope)if not, please just askhttps://youtu.be/QTJ7Lvcysi0
MIPI (LVDS) interface on "zig-zag" (board to board) FPC connector - Page 1
Forum section: electronics / projects

author: Piotar
author_rank: Newbie
timestamp: May 30, 2025, 02:32:58 pm
content: Hello,I am designing a digital video board, which will drive a 4 lane MIPI display.I was wondering, could I use zig-zag connector (for example 45p. 0.3mm FPC CONN) to transfer the differential pair from one board to another???I am planning to set the pinout ...GSSGSSG... There is 0.7mm distance between contact row pins, so I will take into account it, when I make the length match. Approximately data rate will be up to 1Gbps.The example image of the used cable is attached.I will be thankful for any reply!Regards,Petar
MIPI Camera for Raspberry Pi 4 - Page 1
Forum section: electronics / projects

author: jm677zz
author_rank: Newbie
timestamp: November 27, 2020, 04:24:37 pm
content: e-CAM130_CURB, a13MP MIPI camera for Raspberry Pi 4empowered with a built-in image signal processor (ISP), interchangeable M12 (S-mount) lens, and uncompressed 4K streaming capabilities.So if you are looking to integrate a camera into your products for quick deployment to reduce time to market, then e-CAM130_CURB is the right choice for you!Watch the video to know the features of this 4K camera,
MIPI CSI-1 vs MIPI CSI-2 - Page 1
Forum section: electronics / projects

author: sadasivamASK
author_rank: Contributor
timestamp: May 10, 2022, 11:06:42 am
content: Hi,Would like to have some understanding.Does MIPI CSI-1 is compatible with MIPI CSI-2? From my understanding, it depends on the specific "controller" and "camera sensor" using. The two versions of the standard use different physical signalling levels so will not be compatible unless one or other states it supports multiple standards.Reference:https://electronics.stackexchange.com/questions/565062/is-it-possible-to-connect-csi-2-camera-to-csi-1-port?msclkid=3efaea33d04a11ecb04074b132f58ae4Stated as, "The answer will likely depend on the specific "snapdragon board" and "4k camera" you are using. The two versions of the standard use different physical signalling levels so will not be compatible unless one or other states it supports multiple standards. –Tom Carpenter"Example: Camera sensor(MIPI) interfaced with controller(MIPI CSI-2 to USB bridge controller) and stream video via USB 2.0. For data transfer in USB 2.0, from above statement, CSI-2 spec will not be applicable. So, can we use MIPI on both camera sensor and controller for data transfer in USB 2.0?Reference Application note :https://www.infineon.com/dgdl/Infineon-AN90369_How_to_Interface_a_MIPI_CSI-2_Image_Sensor_With_EZ-USB_CX3-ApplicationNotes-v05_00-EN.pdf?fileId=8ac78c8c7cdc391c017d073e56bf6257&msclkid=42e148f0d04f11ecabcd90dded361764States as,"The high bandwidth provided by USB 3.1 Gen 1 puts heavy demands on ICs that connect peripherals to USB. Apopular example is a camera streaming uncompressed data into a PC. As USB bandwidth has increased with version3.1 Gen 1, so has the resolution of cameras that attach to PCs. To address high-bandwidth camera interfacerequirements, an alliance called Mobile Industry Processor Interface (MIPI) created a specification called CameraSerial Interface 2 (CSI-2)"Also any info on pin-out structure for both std...if it is different for both stds.

author: sadasivamASK
author_rank: Contributor
timestamp: June 03, 2022, 05:53:55 am
content: Is my understanding correct?
MIPI CSI-2 TX with LVDS outputs of FPGA - Page 1
Forum section: electronics / projects

author: videogpu
author_rank: Newbie
timestamp: April 12, 2023, 10:29:42 am
content: Hi All,I wanted to share here a project that I have recently finished. It allows to connect simple FPGAs with no dedicated MIPI output to the MIPI inputs of the Jetson TX2 board, and with minor customisation probably to many other boards. The VHDL code implements two lanes + clock, and sends 10 bits Bayer image at 800Mbits/Lane. This is approximately 24 fps for 2592x1944 frame size.The PCB does't use any expensive chips for LVDS->SLVS conversions, just resistors network. Switching between HS and LP modes is done with a cheap DDR3 switch from TI.Would be interesting to hear possible adaptations of this project. I did it mostly for educational proposes, to understand the protocol.VHDL code:https://github.com/VideoGPU/MIPI_CSI2_TXKicad PCB:https://github.com/VideoGPU/FMC_MIPI
MIPI CSI Routing – Concerns About Trace Length and Bends - Page 1
Forum section: electronics / projects

author: electronx
author_rank: Regular Contributor
timestamp: April 30, 2025, 07:56:02 am
content: Hi everyone,I've done the MIPI CSI routing like this, and I'm referring to an example from NVIDIA’s reference design.I'm wondering whether the trace length matching and these sharp bends could cause any issues?I was initially concerned about impedance, but after running simulations, I confirmed that the impedance is within the required range.What are your thoughts?
MIPI DSI adapter + lcd drivers PCB review request - Page 1
Forum section: electronics / projects

author: dartcom
author_rank: Newbie
timestamp: July 15, 2023, 03:23:10 pm
content: This design contains 3 separate boards inside the same pcb (to save costs with JLCpcb). The first board takes a 24-bit rgb stream and converts it to MIPI DSI with the SSD2828 bridge IC, its datasheet can be found here:https://datasheet.lcsc.com/szlcsc/SSD2828QN4_C48596.pdf.The other 2 boards are adapter boards for specific displays. The first display is the LH154Q01 panel, more info about it can be found here:https://www.circuitvalley.com/2020/01/spi-mipi-bridge-fpga-verilog-hdl-ipod-nano-nano-lcd-iphone-mipi-lcd.htmland this is the schematic:https://github.com/circuitvalley/mipi_dsi_bridge_fpga/blob/master/Hardware/Schematic%20PDF/IPOD_LCD.pdfI copied. This lcd is going to be used as a sanity check to test if the bridge IC works correctly, since it requires small bandwidth.The second adapter is for the VS035ZSM panel used in vr headsets, here:https://docs.projectnorthstar.org/electronics/schematicsis the schematic I copied for this board. This is the actual display I want do drive. It has a resolution of 1600x1400, so @60fps the required data rate is 800Mbit/s per lane.The design is a 4 layer pcb with the layers: signals(red) - GND(green) - GND+signals(orange) - signals(blue). Im going to order this board as one design and then split it into 3 by scoring it with a razor cutter.From the given stackup I calculated 0.14mm spacing and 0.166mm track width to get 100Ω differential impedance that MIPI requires. I got the Intra-pair skew to 0mm (according to kicad) and the maximum inter-pair skew to 0.05mm. I looked at some layout guidelines online, and I found inter-pair skews from 10 to 40 ps, I dont know what is correct, and how these delays translate to trace lengths. Are there any other things that I need to get sorted with the MIPI lanes or the dc-dc converters before sending the board for production?Since there is a 10 pic limit per post, pictures of each layer are available here:https://imgur.com/a/0qLzN5JThere is the repo of the project:https://github.com/dartcom/ssd2828-dev
MIPI-DSI immunity to switching noise? - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: November 25, 2024, 12:14:56 am
content: Hi,because of PCB layout constraints I have to place a synchronous-type switching regulator (24V in to 3V3 out running at 2A) next to the MIPI-DSI connector.The inductor is fully shielded and all the power-path traces are as short as they can be (literally 2-3 mm long).How immune is MIPI-DSI to switching noise? Is it ok to place the switching regulator right next to it?Thank you

author: uer166
author_rank: Super Contributor
timestamp: November 25, 2024, 12:30:00 am
content: Looks like they're ~50 Ohm SE impedance diff pairs, so the usual applies:Don't cross GND slots, reduce crosstalk by keeping the offenders away by 5-10 prepreg heights, either don't flood top layer with GND, or if you do, stitch it every 1/10th wavelength of the signal in question, etc etc.It doesn't seem particularly sensitive, just like most high-speed controlled impedance interfaces.

author: ricko_uk
author_rank: Super Contributor
timestamp: November 25, 2024, 02:25:03 am
content: Thank you @uer166

author: Pbtz
author_rank: Newbie
timestamp: November 26, 2024, 09:52:10 am
content: In my experience MIPI is fairly robust in general. I've made it work over 10-inch bodge wire.

author: ricko_uk
author_rank: Super Contributor
timestamp: November 26, 2024, 04:48:18 pm
content: Thank you Pbtz.At what speeds did you do that?
MIPI LCD Display compatibility issues - Page 1
Forum section: electronics / projects

author: eigiman
author_rank: Contributor
timestamp: March 10, 2023, 04:34:53 pm
content: Dear LCD gurus,I tried to repair a broken Voltcraft BS-701+IP endoscope screen (LCD mechanically broken) by ordering an LCD of identical size from a Chinese manufacturer. The resolution is identical (4.5" FWVGA 480x854px), same number of pins on connector (40), and with very similar connector layout in terms of power/data/backlight pins etc.I naïvely thought that one MIPI display with the same connector type could replace another.The new display only shows a white strip at the top and bottom, no image. On a CRT I would have said that the horizontal sync circuit wasn't working, but I have limited LCD experience, and no MIPI experience at all.There was no useful number on the original display that led to a datasheet, but it is clear that both the old and new LCDs use 2 differential inputs.Do I just have to assume that the MIPI interfaces are incompatible, or is there a trick I could try?Thank you!
Mips vrs Dmips - Page 1
Forum section: electronics / projects

author: House91320
author_rank: Regular Contributor
timestamp: August 08, 2011, 05:37:23 am
content: I know that mips and dmips are different measurements of a micro what i was wandering if you had a micro running at 70mips how would it compare to one running at 70dmips.

author: ejeffrey
author_rank: Super Contributor
timestamp: August 08, 2011, 07:39:42 am
content: DMIPS is based on a benchmark that tests a profile of different integer operations. MIPS is based on whatever the CPU manufacturer likes. It could actually be DMIPS, it could be the instructions per second for the fastest instruction, or an average mix of instructions. In any case, its interpretation is highly dependent on the instruction set.

author: westfw
author_rank: Super Contributor
timestamp: August 10, 2011, 12:24:10 am
content: I would not expect the DMIPS rating to EVER be faster than the MIPS rating. DMIPS assumes a certain math precision, so things like 8-bit CPUs come out behind wider processors, even if they have a faster native instruction rate. OTOH, DMIPS is subject to compiler variations, so you're really benchmarking a particular CPU/Compiler/Compiler-option combination (perhaps particularly relevant if there's a non-optimizing "free" version of an expensive "full-optimization" compiler...)
MiraOS - review - Page 1
Forum section: electronics / projects

author: mrburnzie
author_rank: Regular Contributor
timestamp: July 27, 2020, 10:20:50 am
content: Hi!I just found a company called LumenRadio. Next to their own hardware, they have developed an OS too.MiraOS:https://docs.lumenrad.io/miraos/Does anybody have experience with them, I would like to hear some opinions.Thanks!
MiSi battery-free acoustic amplifier - Page 1
Forum section: electronics / projects

author: Vytautas
author_rank: Regular Contributor
timestamp: March 28, 2020, 12:04:25 pm
content: Hi, guys,does anybody have experience with battery-free amplifiers that are installed in an acoustic guitar to pick up the sound from the guitar and transfer it to an amplifying system? Such devices use large capacity (like, 1.5F) capacitors instead of batteries.I have got a MiSi device, and it has some kind of interesting component (indicated with a red arrow in the picture). It is only about 3 mm in size. I popped off the cover, to see what is inside. Two pictures are included (with different focus points). Does anybody know what is it? Thank you.

author: dmendesf
author_rank: Frequent Contributor
timestamp: March 28, 2020, 12:27:28 pm
content: Looks like a MEMS microphone.
Missing transformer - Page 1
Forum section: electronics / projects

author: Goature
author_rank: Contributor
timestamp: April 28, 2016, 06:20:15 pm
content: Hello all!I've been assigned the task of reviving this circuit board. When I received the board, only a few pieces of the transformer was remaining. I havent had much luck trying to find a similar transformer, and I was wondering you could help me on this.The footprint of the transformer is shown in the attached picture. The fuses are rated to 10A. The fuses appears connected in series with the primary of the transformer. The secondary is connected to a rectifier with the following ingraving: "F, T350, GBU, 8M", and then a 7818 regulator.

author: SeanB
author_rank: Super Contributor
timestamp: April 28, 2016, 06:56:59 pm
content: Standard potted PCB mount transformer, likely a 220VAC primary and a dual 9VAC secondary, probably around 500mA rated. The 2 secondaries are in series, and the bridge rectifier probably delivers 24VDC to the regulator.

author: promacjoe
author_rank: Regular Contributor
timestamp: April 29, 2016, 02:38:51 am
content: Question: why would you need a 10 amp fuse on the primary side of a transformer, For a 1 A 18V regulator. There has to be something else on that circuit that requires 10A.

author: SeanB
author_rank: Super Contributor
timestamp: April 30, 2016, 10:46:01 am
content: Those PCB mounted transformers are internally protected, likely there is a SCR or triac drive on the board which has the 10A fuse.RS 347-2672 is a good place to start, looks like it will fit the holes and has the right pinout on it.

author: Jeroen3
author_rank: Super Contributor
timestamp: April 30, 2016, 11:15:08 am
content: Maybe one of these:http://www.gerth-trafo.de/images/PDF/datasheets/GERTH_Data_Series-600.pdfThey have plenty of transformers, they should be able to sell you a fitting one.http://www.gerth-trafo.de/index.php/de/produkte
Missing VGS(th) / VT max. characterististic from a MOSFET's datasheet. - Page 1
Forum section: electronics / projects

author: euzer
author_rank: Regular Contributor
timestamp: May 20, 2022, 02:37:19 pm
content: I've been looking at the datasheet for an n-channel enhancement MOSFET, p/n Diodes Inc ZXMN6A08G (https://www.diodes.com/assets/Datasheets/ZXMN6A08G.pdf) and only the minimum threshold voltage (VGS(th)) is specified, and not the maximum. I would think the maximum value is needed to design with to ensure that the part is turning on. Am I missing something about why the maximum has not been given?TIA

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 20, 2022, 02:54:44 pm
content: Hah, that is weird. Kind of a dick move, yeah.On the upside, it's certainly no more than, somewhat less than 4.5V -- Rds(on) is given for this condition, and it's well saturated by then.Offhand, I would guess typ +/- 1V, being a fairly common range. Logic level parts like this tend to have even narrower ranges (say 0.8-2.0V).You can see from Transfer Characteristics, it's less than 2.5V (plots are typical data, by the way), mind, at higher Vds (10V) and current (graph cuts off at 10mA). Note the linear slope on the semilog plot -- this is in the exponential subthreshold* / cutoff region: we can extrapolate down to lower currents from here, with reasonable confidence. With a slope of about 10x per 0.35V, 0.25mA should be 0.56V lower, or Vgs(th)(typ) ~ 1.89V.*Different meaning of "threshold". Vgs(th) is just measured at whatever low current. The device characteristic transitions from Id ~ exp(Vgs) at low currents, to Id ~ Vgs^2 at high; the transition between these characteristics being this meaning of "threshold". I suppose for small (RF?, IC) MOSFETs, such a current might be close to this characteristic, but they just keep using the same current for ever-larger power transistors, so, obviously they're going to fall lower on the curve, relatively speaking.So, still no (max), other than what can be inferred from Rds(on), and similar shifting-about arguments using the other typical plots.Tim

author: Geoff-AU
author_rank: Frequent Contributor
timestamp: May 23, 2022, 01:40:21 am
content: Seems like it's intended for use as a digital switch. The threshold is telling you it's guaranteed-off below 1V, and the RDSon tells you it has a healthy channel by 4.5V. If you want to guarantee it's on, you need to give it 4.5V. A maximum threshold would only tell you where you've definitely entered the linear region by. But that's probably not very useful for a switch.

author: euzer
author_rank: Regular Contributor
timestamp: May 24, 2022, 08:40:20 am
content: Without the figure I feel it's not possible to judge if the device can be controlled (as a switch) with a 3.3V MCU GPIO. Diodes inc have responded that this device has VGS(th) max = 3V, and the reason a figure was not included in the datasheets originally could be because this limit is not tested during final production test.I am searching for an alternative for an Onsemi NDT3055L.
Mistake in Datasheet? - Page 1
Forum section: electronics / projects

author: johofz
author_rank: Contributor
timestamp: April 14, 2022, 02:04:38 pm
content: Hello dear EEVblog-Community,I recently designed a switching regulator circuit to convert 5V to 3.3V at around 500mA current. So a fairly basic application.I used TIs LMR10510 for the job. Here's its data sheet:https://www.ti.com/lit/ds/symlink/lmr10510.pdfThey provide an example circuit that fits my application pretty well, so I figured I'd go with it to save some time. I did this before and never got burned - until now that is. The voltage coming from the switcher was completely off. It took me a whole day to figure out what was wrong. Turns out TIs example has wrong values for the voltage divider in the feedback-loop. I think it's a typo. They suggest a 100k for R2 but the calculation with the formula provided evaluates to 10k.So what I'm interested in is whether these mistakes are a common thing to look out for. I'm not a lazy person but I made very good experiences soar with sticking to the datasheets. It's time and therefore cost efficient for the work I do.Greetings from Germany!johofz

author: RoGeorge
author_rank: Super Contributor
timestamp: April 14, 2022, 03:06:36 pm
content: Indeed, it should be 10k, not 100k.Click the "Submit Documentation Feedback" link from the datasheet and report the typo.

author: Siwastaja
author_rank: Super Contributor
timestamp: April 14, 2022, 06:41:10 pm
content: Typos and more serious mistakes (i.e., datasheet writer does not understand their own part, or the typical requirements) are quite common. Not in every datasheet of course, but it's always a good idea to verify. Companies like TI have tens of thousands of parts, datasheets are written in hurry and human errors happen.Worse than documentation errors, sometimes parts are actually not very useful because of actual design mistakes. Buggy state machines, wrong UVLO thresholds so that integrated MOSFETs may thermally self-destruct, anything like that.

author: Someone
author_rank: Super Contributor
timestamp: April 14, 2022, 10:25:26 pm
content: Quote from: Siwastaja on April 14, 2022, 06:41:10 pmYes, an example:Switching regulator has an enable pin, datasheet has both upper and lower thresholds for logic.Pulling enable low during operation does not stop the regulator.Checked voltages at the enable pin, well past the worst case off threshold.Connected with the "support" team, their answer: "we cant see any problem, case closed".No further assistance, no demo or example of what their expected behaviour is to say "cant see any problem", no change to the data sheet.Needless to say, I stopped using that brand of switching regulators in designs.Counterexample:MCU perhiperal didn't seem to work as expected.Contacted manufacturers support with explanation.1 day later received a polite email pointing to the one tiny footnote in the 1000+ page datasheet collection saying it was expected behaviour.I continue using that brand of MCU, despite their crappy documentation that hides the occasional critical detail. Thats why we have dev boards.
Mistery VGA? Plug board - Page 1
Forum section: electronics / projects

author: dobsonr741
author_rank: Frequent Contributor
timestamp: May 11, 2025, 01:39:01 pm
content: Anyone recognizes this board? Goggle did not. Fits into a VGA port of a monitor or PC. No silk screened text to go off of. No clear indication which header pin might be power, as all non GND traces are thin and there’s no recognizable bulk capacitor. I would start mapping out the VGA pins to components next, but not sure worth the investment without knowing what this piece might be good for.

author: Ian.M
author_rank: Super Contributor
timestamp: May 11, 2025, 04:22:36 pm
content: Whatever it is, its *NOT* VGA. Look at the back of the board and you'll find pins 3 and 5 are shorted, as are as pins 6 and 9. Compare that with the VGA pinout, and you will find BLUE is shorted to GND, and PWR (5V for EDID) to RED_RTN, which is almost invariably a ground. *DON'T* plug it in to a graphics card unless you don't mind letting the magic smoke out!

author: dobsonr741
author_rank: Frequent Contributor
timestamp: May 11, 2025, 08:30:41 pm
content: Thanks—that’s exactly what I needed to know: it’s not VGA.

author: amyk
author_rank: Super Contributor
timestamp: May 11, 2025, 08:31:20 pm
content: Where did you find it? That might help figure out what it's related to.
Mistery SCL1054-V4 IC - Page 1
Forum section: electronics / projects

author: Phaseseeker
author_rank: Regular Contributor
timestamp: April 17, 2021, 08:45:08 am
content: Like the title said, I need some help identifying the chip in the picture:since the board was manufactured by IPM and other chips are marked "IPM", the third row is probably an internal code that is useless for identification, but "SCL" is an actual IC prefix, so i think that "SCL1054-V4" is a valid part number.I searched online for a datasheet but the only thing i found are the usual Chinese websites trying to sell me other chips (which I don't need). The National databooks I found weren't of much help.I tried decapping one of those, and on the die I found a RCA logo and another code, but searching for this one I found even less data.The chip is packaged in a PLCC-68 from the processor board of an Italian public payphone from the early '90s; if I had to guess I'd say it's some kind of communications chip (the phones are capable of talking to the phone company over the phone line using the HDLC protocol, but there isn't any kind of communications chip on the actual "line interface" board). I don't know how many of those were made, but I doubt that there were enough phones to justify a fully custom IC (especially considering that I have some boards that were made 3/4 years later that are vastly different; if they had a custom chip made I doubt they'd stop using it in the later revisions), so it's probably some off the shelf component.Edit: I quickly checked the PCB with the multimeter and I found that the chip is connected to both the data and the address bus of the main processor; looking at the die (I would post a photo but with my microscope I can't really take a good picture of the whole die) it seems that it's got at least some amount of memory (roughly half the area of the chip). I don't think it's actually a memory chip because the phone has a 8K EPROM, a separate "configuration" 2K EPROM and a 2K SRAM chip, plus whatever RAM the MCU has onboard.

author: Benta
author_rank: Super Contributor
timestamp: April 17, 2021, 02:39:44 pm
content: The part number makes me think of SiTel Semiconductor, this would also fit to the application. National used to fab for SiTel and took some of the parts into their own portfolio (DECT mainly).SiTel is now part of Dialog Semi.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 17, 2021, 10:06:42 pm
content: yepOld logo of National Semiconductor until 1994but googlefuu did not show anything, could be a custom chip ??
Misuse of a TA7642 (MK484) - Page 1
Forum section: electronics / projects

author: richard.cs
author_rank: Super Contributor
timestamp: October 27, 2014, 05:11:27 pm
content: The well known AM TRF receiver on a 3-pin chip. Datasheet:http://www.shenzhensum.com/products/datasheet/TA7642.pdfWhile the last stage is nominally a detector it looks (from the equivalent circuit and from the fact that people have made regenerative sets from them) like if the 100n is left off of the output and perhaps the bias is tweaked a little then most of the amplified RF still comes out. If so that would make it rather useful for something I'm working on which needs a fairly wideband input stage centred on 1 MHz. I'm going to order a few and have a play but in the meantime a few questions:Is there a similar part without the detector (or with the intermediate connection brought out)?Has anyone here used one for this purpose?Does anyone have any spice models for the part?Failing that some suggestions for transistor parameters to try in a model of the equivalent circuit would be appreciated.ThanksRichard

author: dannyf
author_rank: Super Contributor
timestamp: October 27, 2014, 07:34:19 pm
content: I have used it as an if amplifier 455khz. No problem. And with the added advantage of built in agc.selectivity however isn't that great.

author: SeanB
author_rank: Super Contributor
timestamp: October 27, 2014, 07:47:29 pm
content: What about using one of the MAR series microwave amplifiers? Yes incredible overkill, and you will need to take care not to make an oscillator out of it but they actually do have a good gain figure down to audio frequencies. Plus as a bonus you have 50R input and output impedances.

author: dannyf
author_rank: Super Contributor
timestamp: October 27, 2014, 11:48:21 pm
content: Those MMICs have very low input impedance, making them unsuitable for tuned RF circuits, unless you do impedance matching.

author: richard.cs
author_rank: Super Contributor
timestamp: October 28, 2014, 12:54:11 pm
content: Danny - you used it purely as an IF amplifier without making use of the detector? i.e. 455 kHz in and out. This is the kind of thing I have in mind.Sean - I've looked at the microwave amplifiers. The low input imedance is probably ok in my application and I think they should work with care but several stages would be needed for similar gain. This may be what I end up with, I'll already be using that type of thing elsewhere in the design for stuff at around 100 MHz.

author: dannyf
author_rank: Super Contributor
timestamp: October 28, 2014, 03:46:45 pm
content: No. In my case, it was if plus the detector.I haven't attempted to drive an if can with it but don't see why it cannot be done - the bias in the last stage isn't too low.
Mitigating switching noise in a boost converter. Raise or lower switching freq? - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: July 29, 2019, 06:50:18 pm
content: I'm working with an LTC3787 boost converter and I'm trying to reduce the amount of switching noise making its way around the board. I know that there's a handful of layout changes I can make, but I'm trying to find as many tweaks with the circuit as possible.The general tradeoff for switching frequency is generally the greater the switching frequency, the greater the efficiency, but the output is generally noisier, correct?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 29, 2019, 07:14:22 pm
content: Noisier in what ways? Higher Fsw is easier to filter the ripple (fundamental and low harmonics), at the expense of greater switching loss (and somewhat higher average HF noise). Commutation noise (that associated with the switching event itself) depends only on the layout and filtering (the peak value of the noise, that is).We typically call the former "EMI", and the latter "RFI".An EMI choke (common mode) typically has little to no effect on RFI, partly because it is hardly effective at such frequencies (most chokes are effectively small capacitors at that frequency), but also because the equivalent circuit coupling into the conducted or radiated emissions is different at those frequencies.EMI is easily filtered, through DM and CM filtering and conventional components; RFI is harder to filter, requiring a more carefully constructed filter with a compact star grounding topology and shielding if necessary, or can be treated at the source by dampening the switching edges or improving layout.Tim

author: Pack34
author_rank: Frequent Contributor
timestamp: July 29, 2019, 07:28:28 pm
content: I'm seeing a lot of high-frequency noise in my lower voltage supplies on the board. I know that with the existing design the low voltage regulator goes under the high voltage boost and is causing issues. Through initial testing of increasing-and-reducing the switching frequency of the boost converter, the high-frequency noise is lessened on the 3v3 digital rail and the 2v5 analog.The issue is mainly the noise being measuring on some ADCs, with the artifact being removed once the switching frequency of the boost converter was reduced.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 29, 2019, 10:07:02 pm
content: Circuit?Tim

author: bob91343
author_rank: Super Contributor
timestamp: July 29, 2019, 10:13:22 pm
content: Changing switching frequency won't do what you want. The transistion speed will remain the same. To change the spectrum of the noise significantly requires a different topology or much faster (or slower) semiconductors.
MitM Streaming - Page 1
Forum section: electronics / projects

author: PlainName
author_rank: Super Contributor
timestamp: August 13, 2025, 10:54:53 pm
content: I have a device that will pair with a phone or PC (Bluetooth, obvs.) or whatever and stream audio. But to connect to the source it has to be turned off (actually battery removed because there is no power switch) and then it will reconnect with whatever it is paired to. Which can be one of only two things. As you can imagine, it's a bit of a drag.My potential solution is to have a device that fronts this one and acts as a man in the middle. This new device will easily pair with multiple sources, and easily connect to the preferred one (and then switch, if required, to a different one). So basically Bluetooth streaming client one end, Bluetooth streaming host the other.Any suggestions for achieving this, or knowledge of an existing one I can go and buy? Needs to be small and battery powered.

author: PlainName
author_rank: Super Contributor
timestamp: August 14, 2025, 07:17:59 pm
content: Seems there are a bazillion 2in1 streamers which either take 3.5mm jack input and send over Bluetooth, or receive from Bluetooth and send to the jack. A couple of those back to back should determine whether the idea is useful or not, and they're cheap enough.https://www.amazon.co.uk/dp/B07198BBZNis middle of the road example.If this works then I'll look at a DIY one that removes the DAC-ADC link. There are some that have an optical interface which might resolve that, but it would all want to be a small box anyway.
Mixed-signal modular system GND scheme question ? - Page 1
Forum section: electronics / projects

author: intel386
author_rank: Newbie
timestamp: March 29, 2018, 03:06:01 am
content: Hi,I'm attempting to create a sensitive mixed signal system (24 bit or more audio) compose of a backplane and stacked modules on 2.54mm headers.It is multi-channel and channel's modules are well separated with independent supplies of their own.The only common module is the DSP, therefore all separate GNDs of all modules will meet at a single point is the DSP's supply GND.My questions are :Please take a look and see if there is any problem with my wiring ( quick draft attached below ), both in DC and low-freq noise ( shared impedances in GND return paths ) and HF, spiked noise ( digital and analog return flows ) ?Is there any advice/caution regarding making a system on backplane ? The 2.54mm hdrs are good enough for 50-100MHz signal ? Any caution making connection through these tiny pins, especially with GND involved ? Should I treat the BCKPLN as a board of wires and traces only, or make use of it's copper planes for some further benefits ?ThanksHere is a quick draft of system wiring :
Mixing common positive and common negative DC equipment. - Page 1
Forum section: electronics / projects

author: paulca
author_rank: Super Contributor
timestamp: March 26, 2023, 11:02:26 am
content: I have two solar chargers.One is common positive the other is common negative.If I draw the schematic of these in parallel with the same battery and different panels, in my head, I can't see a problem. I mean if either the positive or negative between the two should touch there could be a short, but... that's always the case anyway.The common positive controller will "float" relative to the battery positive. However that is the same positive that is connected to the common negative controller anyway. So they share the same - and the same + potentials.Solar panels do have metal frames, however I'm not exactly sure that makes a difference. If it's galvanically connected to one or the other and it's the same on all panels, the only current that could flow would be the differential voltage between those particular panels floating potential and ... that's always going to be the case of independant strings anyway.Where is the gotcha? Assuming you don't do anything stupid like not verify the earth is always - on both and don't connect the + and - to Earth reference at the same time!EDIT: I tested the common positive controller. It's completely isolated from it's case and earth on both + and -.

author: Terry Bites
author_rank: Super Contributor
timestamp: March 26, 2023, 02:11:11 pm
content: Share your schematic?

author: paulca
author_rank: Super Contributor
timestamp: March 26, 2023, 02:28:12 pm
content: What I have so far. Tried to show the common-ing through the blocks.
Mixing external power and USB ground - Page 1
Forum section: electronics / projects

author: docu
author_rank: Newbie
timestamp: August 21, 2016, 12:53:56 am
content: For a circuit I am designing, I will be controlling a motor over USB. The USB connection will be handled by an ATmega32U4 (which will also be powered over USB at 5V). The motor will be powered by a 12V wall adapter which will be delivering power through a barrel jack.Can I tie the USB ground to the ground from the 12V supply? Is there a proper method for joining these two circuits together?

author: timb
author_rank: Super Contributor
timestamp: August 21, 2016, 01:08:15 am
content: Yes, you can tie the grounds together. Shouldn't be a problem.

author: Ian.M
author_rank: Super Contributor
timestamp: August 21, 2016, 01:18:23 am
content: It *may* be problematic if the 12V wall wart has its output internally grounded, as that could cause a ground loop. If its got a ground pin on its AC input, check for continuity between that and output 0V.If you have continuity, it will probably work fine as long as it and the PC are running from the same wall outlet, but if the wallwart is on a different circuit, and there is a significant ground potential difference, it could even damage your PC if you don't optoisolate the motor interface.If the wallwart output is fully floating, you shouldn't have any problems unless the motor itself introduces a ground through the equipment it is part of.

author: docu
author_rank: Newbie
timestamp: August 22, 2016, 12:22:41 am
content: Quote from: Ian.M on August 21, 2016, 01:18:23 amEh, I will just keep the two supplies independent and optoisolate the motor controllers, as you mentioned. Thanks!

author: Ian.M
author_rank: Super Contributor
timestamp: August 22, 2016, 12:51:42 am
content: The other option is a heavy duty grounding strap from the PC chassis to the motor controller and onwards to the motor frame + always running everything from a single socket. The grounding strap diverts any unexpected ground currents away from the relatively delicate traces*on the PC motherboard and motor controller.* Even if a board has a solid ground plane, its not unusual to have a thermal relief round the ground pad for the USB connector to improve solderability, so an excessive ground loop current can blow traces like a fuse even on well designed boards.