Good quality low profile PCB interconnect cables - Page 1
Forum section: electronics / general

author: peter-h
author_rank: Super Contributor
timestamp: August 22, 2025, 08:39:05 pm
content: The Chinese use all kinds of stuff which I can't find who makes it...Basically the cheap crap is like the connectors on LCD displays which you slide a flat cable into and then in a very fiddly way move a bar across to lock ithttps://www.mouser.co.uk/ProductDetail/710-687120183622but it will come out if you pull it. Chinese versions can be found for pennies.A better one is like this (zoom in on the photo)https://www.mouser.co.uk/ProductDetail/798-FH63S20S05SHbut Hirose don't make the flat cable for that; there is a spec for it and I think this might work (well Mouser tech supp thinks so)https://www.mouser.co.uk/ProductDetail/906-050R20-152BThen for 10x the cost you get thishttps://www.amphenol-cs.com/product-series/flexible-printed-circuit-assembly.html?page=1which is clearly the proper jobI am after about 20 ways, 15cm long, horizontal format so under 6mm high, and not easy to pull out.In the old days one just went for thishttps://cpc.farnell.com/harting/09-18-520-6903/header-right-angle-20way/dp/CN12951but it is HUGE...The other old way was to make your own with these headers on the endhttps://sa.rsdelivers.com/product/te-connectivity/5746613-3/te-connectivity-16-way-idc-connector-plug-for-2/7185091and I used to buy thousands of them but we had a fairly significant defect rate with IDC.I wonder what I am missing? Is there some obvious low cost robust product? I don't mind if it comes from Aliexpress.Thank you for any tips.

author: shabaz
author_rank: Frequent Contributor
timestamp: August 22, 2025, 09:11:26 pm
content: Hi,PicoBlade is quite nice, 1.25 mm pitch, available in right-angle through-hole with 3.5 mm height. Ready-made cables come in 150 mm length as standard.However, max number of circuits is 15, so it would depend if you're willing to split across two connectors, say two 10-way connectors.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 22, 2025, 11:27:42 pm
content: QuoteThe term you're looking for is "FFC" ( Flat Flex Cable)Plenty of very cheap FFC cables at LCSC.https://www.lcsc.com/category/920.htmlConnectors :https://www.lcsc.com/category/545.htmlFor connectors, the back-locking type are easier to use as it locks on the opposite side to the flex entryFor examplehttps://www.lcsc.com/product-detail/C587969.html

author: thm_w
author_rank: Super Contributor
timestamp: August 22, 2025, 11:47:40 pm
content: Quote from: peter-h on August 22, 2025, 08:39:05 pmYou can also get 1.27mm pitch IDC:https://www.aliexpress.com/item/4000796015741.htmlBut as mentioned above, if you want something robust just go with multiple connectors. JST SH XH whatever will fit.Quote from: mikeselectricstuff on August 22, 2025, 11:27:42 pmYeah but he doesn't want them because they are "easy to pull out".I wouldn't care if its an interboard connection not accessible to the user. But maybe there is some other reasoning behind it.

author: peter-h
author_rank: Super Contributor
timestamp: August 23, 2025, 05:00:14 am
content: There can be vibration as in say a vehicle.The LCSC site has loads of cables probably compatible with the Hirose connector but not with reinforced ends.Less than 20 is OK for me but this doesn't seem to be a problem.I did notice the methods which use separate wires and these are sometimes seen in stuff like CD players. Maybe it is cheaper to pay very low paid people to do the terminal crimping?

author: peter-h
author_rank: Super Contributor
timestamp: August 27, 2025, 01:13:42 pm
content: I got the samples from Mouser. Interesting results.The Wurth connector is very fiddly to lock. It is like so many from China but Wurth trade on the German nameTo its credit, once locked, it is very difficult to get the cable out.The Molex connector uses a rocker mechanism, easy to operate, but the cable does pull out quite easilyThe Hirose is the most robust connector, with extra solder pads and a rocking lock - very nice to operate, but the cable does pull out. In fact I can hardly tell any difference between locked or not, except that when unlocked the flat cable is located properly laterally, whereas when locked you can push the cable in with a misalignment of > 1mm which is daftTurns out that Mouser recommended the wrong cable for the Hirose connector. The PARLEX cable they recommended (immediately above) looks nothing like the one shown in the photo here:https://www.mouser.co.uk/ProductDetail/798-FH63S20S05SHand that must be the thing to pursue. The data sheethttps://www.mouser.co.uk/datasheet/2/185/FH63S_20S_0_5SH_CL0580_4419_0_00_2DDrawing_0001345-2940709.pdfshows a drawing of the end of the cable and obviously it has the locking features, but who makes it??Mouser have no idea and "will get back to me".It is this:https://www.mouser.ca/new/hirose/hirose-fh63s/The other two connectors are IMHO unsuitable for anything "industrial".

author: tom66
author_rank: Super Contributor
timestamp: August 27, 2025, 01:19:07 pm
content: Maybe consider something like an I-PEX connector, e.g. CABLINE UA. In volume they're under a dollar each.

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 27, 2025, 02:03:01 pm
content: Quote from: peter-h on August 27, 2025, 01:13:42 pmThe only manufacturer for these ready-made punched FFCs I could find isElectronAixin Germany. The ends are punched after the FFC has been cut to length and the stiffener affixed to the end. I'd contact the sales person there. For FH63S, their compatible FFC series is calledFACH6, and looks like it might fit your needs.(As a hobby, I play with low-resolution (up to 480×480) display panels and modules, and often investigate what is available. Flat flex cables are ubiquitous in display panels and modules, and some FFCs are even shielded with ground "planes"; FH63S supports that kind too. Excellent for high-frequency digital signaling if you also use ground conductors between signals or differential signal pairs: you often see LVDS video mentioned in the FH63S use cases. I have no experience with, and no connection to these otherwise.)

author: peter-h
author_rank: Super Contributor
timestamp: August 27, 2025, 02:04:55 pm
content: Thank you, NA. You have probably found it! I am still amazed Hirose do not make the cables.The I-PEX multiple ones seem to be all for individual wires, which is another way to do this, but I would prefer to avoid it.

author: tom66
author_rank: Super Contributor
timestamp: August 27, 2025, 02:25:18 pm
content: Quote from: peter-h on August 27, 2025, 02:04:55 pmI-PEX connectors come pre-crimped, so you buy them assembled with wires installed. You don't want to try crimping a 0.3mm pitch cable yourself...

author: peter-h
author_rank: Super Contributor
timestamp: August 27, 2025, 04:06:31 pm
content: The I-PEX ones terminate onto a ribbon cable, like a SCSI cable. I can't find anything small on their site like say a 20-way one.

author: thm_w
author_rank: Super Contributor
timestamp: August 27, 2025, 10:34:45 pm
content: Quote from: peter-h on August 27, 2025, 01:13:42 pmSearch of fh63s ffc found this:https://www.electronaix.com/en/ffc-jumper/ffc-cable-05mm-with-sidecatcher-for-hirose-fh63s-fach6.htmlThe catch design seems to vary depending on the brand, so you can get the cable custom made to match the length and catch type you need. JLC would be able to do it if you design yourself, or plenty on alibaba that can probably do it if you just give them the connector PN:https://www.alibaba.com/product-detail/High-Quality-Oem-Customized-0-5mm_1600489834865.htmlLooks like Model S uses a similar one:https://service.tesla.com/docs/ModelS/ServiceManual/en-us/GUID-2885461A-FD5F-4170-B18B-64B3AC45E7D6-online-en-US.jpghttps://service.tesla.com/docs/ModelS/ServiceManual/en-us/GUID-EFEBBA89-FA89-4285-B862-2908A00F2910.htmlIn other places like the TCON where the cable is not going to move around a regular square FFC is used. You'll also sometimes see the cable taped down or siliconed in place.

author: nctnico
author_rank: Super Contributor
timestamp: August 28, 2025, 12:25:22 am
content: Why is it a problem that the cable pulls out? I have used these type of connectors (FFC) in many projects and cables being pulled out is not a problem. These type of connections are used in billions of devices reliably. Cables should not be pulled on anyway. The only thing I can imagine is a mismatch between the thickness of the FFC and the thickness the FFC connector is designed for but that is a matter of reading the datasheets.

author: peter-h
author_rank: Super Contributor
timestamp: August 28, 2025, 07:53:43 am
content: I need something which can withstand a bit of vibration. Also some of these connectors are really flimsy, and cannot really be regarded as reusable.QuoteYes that is the link posted by Nominal Animal. I've emailed them. I still cannot believe Hirose don't make the cables.

author: tom66
author_rank: Super Contributor
timestamp: August 28, 2025, 08:06:21 am
content: Quote from: peter-h on August 27, 2025, 04:06:31 pmCABLINE-UA II is available in 26 ways and 0.3mm pitch. But FFC/FPC is also another option - depends on what you're doing.Nice thing about these cables is they are individually shielded micro coax 50 ohm terminated, so ideal for high speed.

author: peter-h
author_rank: Super Contributor
timestamp: August 28, 2025, 10:22:22 am
content: Those micro coax cables are amazing. They are used a lot in drones for MIPI and such. This is a 26 way one and the price is finehttps://www.digikey.com/en/products/detail/i-pex/20498-026E-41/24394713but I see only this interconnecting cable, at one helluva pricehttps://www.digikey.com/en/products/detail/i-pex/82068-100B-02-D/24394694With a 20 way cable I can make every 2nd a GND, at least on a part of it. I will be running 21MHz SPI and 375kHz I2C over it, plus some DC signals. The SPI can be carefully risetime tweaked to avoid ringing.No reply from Electronaix... no surprisePerhaps a German person here can ask them.I also found that the Molex connector grips really well if you use a 0.3mm thick cable, not the 0.26mm one recommended by Mouser. Clearly there is a lot more to this stuff to get it right.But Hirose are not the only outfit doing notched connectors and cables. Molex does this:https://www.molex.com/en-us/products/part-detail-pdf/2004850420?display=pdf20 way cable:https://www.molex.com/en-us/products/part-detail-pdf/150160211?display=pdfand this (ex stock from Mouser etc) looks way easier than the Hirose + "non-communicating German cable mfg" optionThat connector also comes in a "grounded" versionhttps://www.molex.com/en-us/products/part-detail-pdf/2004850620?display=pdfwhich seems to be intended for shielded (they call it "LVDS") cables, which cost 5x more.

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 28, 2025, 03:04:31 pm
content: Quote from: peter-h on August 28, 2025, 10:22:22 amLVDS = Low Voltage Differential Signaling, very commonly used in laptops and displays between the video output circuitry ("graphics card") with parallel digital outputs, and the LCD/TFT/OLED/etc. circuitry in the display panel. These usually have 18 or 24 data signals (6 or 8 each for red, green, and blue), a clock, and one or two sync signals, so 27 sounds very typical. With 1920×1080p at 60Hz, on a standard 1080p laptop display, the signal rate is 117 MHz. It's over the hinge in a typical laptop, too.They still tend to be taped down with polyimide ("Kapton") tape, or ~1mm thick double-sided tape, too. Even the non-notched FFCs stay put that way.

author: peter-h
author_rank: Super Contributor
timestamp: August 28, 2025, 04:34:20 pm
content: In volume production, the stuff has to be dirt cheap, but also they have more options e.g. sourcing obscure chinese parts is fine if you are buying 100k-1M, and bodges like using tape (to hold the cable in place) are fine because you buy the tape pre-stamped, 1M piecesI am just trying to do a decent job on a product which will be a maximum 1k batch size...Maybe I should be looking at LCSC for notched cable+connectors. Much cheaper if they do them.

author: nctnico
author_rank: Super Contributor
timestamp: August 28, 2025, 09:35:46 pm
content: Quote from: Nominal Animal on August 28, 2025, 03:04:31 pmNot quite. LVDS uses lanes where each lane consists of 4 data pairs of data and 1 clock pair. For a 1080p60Hz display, typically 2 lanes are used at a clock rate of around 65MHz. The video data and sync is encoded in the LVDS stream (JEIDA or NS format). Higher resolutions use more parallel lanes. Older displays tend to use parallel data (24 bits, clock, vsync, hsync and data enable at CMOS/TTL levels). Typically on a 40 pin FFC connector.

author: tom66
author_rank: Super Contributor
timestamp: August 28, 2025, 10:06:21 pm
content: Quote from: nctnico on August 28, 2025, 09:35:46 pmIf we're really being pedantic, LVDS doesn't refer to anything other than an electrical signalling layer that uses 3.5mA constant current through a differential resistor of ca. 100 ohms, with a common mode voltage of around 1.2V. I have encountered "LVDS displays" that implement 5 lanes of data plus 1 clock for YCbCr 4:2:0 for instance, there really is very limited standardisation.

author: thm_w
author_rank: Super Contributor
timestamp: August 29, 2025, 12:49:44 am
content: Quote from: peter-h on August 28, 2025, 04:34:20 pmI don't think they buy precut tape, they just sit someone on the assembly line and get them to do it. Tape dispensers are not expensive.JLC customflex pcbis only ~$1-2 each and no minimum quantity.Alibaba sellers have no problem doing 100-200pc minimum orders for custom FFC, if you don't want to design it yourself.

author: peter-h
author_rank: Super Contributor
timestamp: August 29, 2025, 03:51:10 pm
content: I did look at JLC flex PCBs (I used JLC for prototypes; they are great) but not sure they can cut them with a notch to go into these connectors.I finally got a reply from Germany:FFC 0,5mm Same 20P 200mm (4,75/4,75/10/10)(0,035x0,32) 105°C 60V HIROSE FH63S Au RoHS/REACHMOQ 100 piecesPrice: 3,00USD/1LT 4-6 WeekDelivery: EXW TaiwanNot really worth it if the Molex version works.

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 29, 2025, 03:54:26 pm
content: Quote from: nctnico on August 28, 2025, 09:35:46 pmNo, that's typically either MIPI DSI or embedded displayport or some other similar data protocol, on top of LVDS hardware; an extremely common mistake. LVDS really is just the underlying electrical signaling standard, TIA/EIA-644. About say fifteen-twenty years ago, many laptops still used a direct parallel 18-bit/24-bit RGB interface to the TFT drivers using plain "LVDS" (same electrical signaling but common ground, not pairs), and not even FPD-Link, which uses just four LVDS pairs (three data pairs and one clock pair) for 18-bit RGB.

author: nctnico
author_rank: Super Contributor
timestamp: August 29, 2025, 04:13:25 pm
content: Quote from: Nominal Animal on August 29, 2025, 03:54:26 pmThat depends on the display. Not all displays you can buy are using MIPI-DSI. I've done quite a few projects involving all kinds of displays so I know my way around where it comes to displays. I've interfaced displays needing 4 LVDS lanes to feed enough data in for the resolution and refreshrate. For industrial displays, LVDS is still used a lot because you can bridge longer distances without needing fancy cabling. There is also a newer display interface standard for industrial displays to replace LVDS called Vx1 (v-by-1) which also works over longer distances.

author: peter-h
author_rank: Super Contributor
timestamp: August 29, 2025, 05:55:29 pm
content: Interestingly some 32F4 chips do MIPI. That is, AIUI, 700MHz min, and you need a full frame buffer so lots of RAM.I am just using SPI

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 29, 2025, 06:48:42 pm
content: Quote from: nctnico on August 29, 2025, 04:13:25 pmNor did I claim they did. The very first display standard using LVDS signaling was FPD-Link, and it has had several later versions too; I think FPD-Link III is the latest one, but nowadays not used as much as the other comms standards.LVDS itself does not have any protocol associated with it, even though some use it erroneously as a protocol term. It is just the hardware-level interface, and the comms protocols over it can be basically anything. With displays, there have been several different ones over LVDS.Quote from: nctnico on August 29, 2025, 04:13:25 pmI've found that people who have worked in depth in some niche, tend to assume that their assumptions apply more widely than they do. It's the "if you only ever use a hammer, you start believing it is the only tool you need, and later that it is the only tool that exist" variant of the old adage about hammers and nails.Quote from: peter-h on August 29, 2025, 05:55:29 pmIt is quite common in SoCs, too. I've been seeing both MIPI DSI (displays) and CSI (cameras) more and more in smaller Linux SoCs in the last few years, including in later Raspberry Pis. There are also chips likeTI SN65DSI86,Lontium LT8912B,Analog Devices ADV7535that convert MIPI DSI display output to embedded DisplayPort or HDMI, to connect the SoC to an external full-sized display. (That said, the SoCs geared towards media box type use do tend to have built-in HDMI or DisplayPort.)I've even seen HDMI input chips and break-out boards with MIPI CSI output at AliExpress (with murky/missing HDMI/MIPI licensing) for treating HDMI input as a camera video source.If you go look at the chips used in these, you'll find all sorts of restrictions and licensing issues, which makes using them in ones own designs quite difficult, unless you have a backing of a company willing to buy the necessary licenses for some thousands of units at a minimum.Quote from: peter-h on August 29, 2025, 05:55:29 pmI recently discussed with SiliconWizard about SPI-connected displays. Some of these, like those using ST7789VW controller can use up to 62.5 MHz SPI clock, if the signal is clean enough, meaning that you can transfer about 3,900,000 pixels at RGB565 per second, these having their own internal framebuffers (which are horribly slow to read).As a practical example,ER-TFT1.95-1(240x282-pixel 33mm×38mm visual area IPS panel, has a TE output signal) has a GC9307 controller that claims to 100 MHz data write SPI clock support, but that is likely limited to somewhat less by the signal integrity over the FPC. A full screen update takes about 1,613,000 SPI clock cycles using 262,144 colors, or about 1,076,000 SPI clock cycles using 65,536 colors, so it can do quite fast full-screen animation via SPI as long as you can use high enough SPI clock.So, "just SPI", is a relative term...

author: tom66
author_rank: Super Contributor
timestamp: August 29, 2025, 06:50:45 pm
content: You don't need a full frame buffer for MIPI DSI. Also there are bridge ICs that can take parallel RGB and output MIPI DSI, for instance Toshiba makes one. They are a pain to use, but they do work fairly well.The nice thing about MIPI DSI is most of the timings for the common displays match the VESA CVT modes, which means you can have an interface that can drive VGA -and- MIPI DSI. That's super useful for lots of tests.Source: have a board that has MIPI DSI 1080p display on it and it definitely does not have a full framebuffer integrated.

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 29, 2025, 07:15:49 pm
content: Quote from: tom66 on August 29, 2025, 06:50:45 pmFPGA?As far as I understand, the source does need to generate the data for every pixel for each frame at the specified frame rate. FPGAs can do the same look-up tricks that old home computers and game consoles did back when they couldn't afford enough RAM for framebuffers: character generators, tile buffers, and other such stuff based on smallish look-up tables.(As a slightly later example from early PC era, a typical 8×16 font was only 4096 bytes, and a 80×30 text buffer 2400 bytes for font glyphs, and another 2400 bytes for 16 foreground and 16 background colors, so a technically 640×480 16-color text mode display only needed under 9000 bytes to implement, compared to the 153,600 bytes a 4-bit per pixel framebuffer would.)

author: nctnico
author_rank: Super Contributor
timestamp: August 29, 2025, 08:17:02 pm
content: Quote from: peter-h on August 28, 2025, 10:22:22 amFor SPI having the clock between two grounds is good. The rest (MISO, MOSI, CS) can be grouped. Also, if the boards are mounted on a metal chassis, make sure the board ground is connected to the chassis directly. No beads, no capacitors. It will help to pass EMC testing (both radiated and immunity).

author: tom66
author_rank: Super Contributor
timestamp: August 29, 2025, 08:59:42 pm
content: Quote from: Nominal Animal on August 29, 2025, 07:15:49 pmYes, the source does need to generate pixel data for each line, although there are some tricks you can perform, like generating data on the fly for e.g. a character grid.Our source is an FPGA in this case, but these tricks can equally be done on microcontrollers that are fast enough (probably not for 1080p, but I'd have thought something like 640x480 would do).A trick I used a long time ago was the parallel master port of a PIC microcontroller. Pixel data was read out from a line buffer via DMA. I would generate the line during the previous line time. If I recall correctly, the resolution was about 320x240 and the frame rate around 30Hz. I would store a list of drawing operations line horizontal, vertical, and filled lines/rectangular regions and basic text, and calculate the "result" or those lines on the fly. Provided the scene did not get too complex, this worked well enough... you had to be careful with what you tried to draw, though.

author: thm_w
author_rank: Super Contributor
timestamp: August 29, 2025, 09:54:05 pm
content: Quote from: peter-h on August 29, 2025, 03:51:10 pmI would hope so as its in their sample image:https://jlcpcb.com/capabilities/flex-pcb-capabilitiesEverything should be laser cut. Other than maybe the FR4.

author: peter-h
author_rank: Super Contributor
timestamp: August 30, 2025, 01:14:15 pm
content: That would make a lot of sense if you needed a flat cable which has bends in it e.g.Years ago this sort of stuff was incredibly expensive.Obviously if you do it this way, you can use your choice of PCB mounted connectors, of which there is a vast range. But then you need to add the assembly cost i.e. paste and reflow.

author: peter-h
author_rank: Super Contributor
timestamp: September 02, 2025, 10:07:52 am
content: The Molex one is by far the bestGoes in easily and doesn't come out at all unless you press on the light brown plastic tab.https://www.mouser.co.uk/ProductDetail/538-200485-0420https://www.mouser.co.uk/ProductDetail/538-15016-0211

author: thm_w
author_rank: Super Contributor
timestamp: September 02, 2025, 09:14:27 pm
content: Quote from: peter-h on August 30, 2025, 01:14:15 pmYes it used to be expensive, now its probably the same cost as the premade molex cable, or less.So if you ever need to second source you have an option.

author: peter-h
author_rank: Super Contributor
timestamp: October 09, 2025, 10:57:56 am
content: The one above works great