More alternatives used in markets in Shenzhen China
www.icgoo.net
www.ickey.cn
www.hqew.com
www.szlcsc.com
And for more international parts (still used in mainland a lot)
www.eciaauthorized.com
Octopart is a more generic site for discovering chips and getting an idea of the price, but still it fetches crappy prices from Digikey, Farnell, Mouser, etc.
If your product is being made in China and you are making the design choices, a quick Taobao search (or using the above links) is great to see how popular a part is. Not recommending to buy parts from Taobao though (unless you are more seasoned). There are also alot of agents that can source parts maybe 1-2 levels below the original factory. Their prices are so good it's unbelievable but they are hard to find and validate. Having volume also helps.
Seconding LCSC here, their prices are pretty damn good for chinese market stuff (and for international musthaves they carry pretty good stock), english support is decent and the shipping combo with PCBs from JLCPCB makes it a nobrainer.
Can you order just a few components, for hobbyists, or are they for big runs? I'm thinking 50-100 resistors and such, for making one or two of whatever I'm making.
They also sell cut tape. So you can order from 1 to 100 parts. There are however some parts that have MOQ of ~50, but those are so cheap that 100 of them would be less than 10 USD.
The cable itself is easily purchased anywhere, there are countless vendors on AliExpress. But I want the connector so I can get something else custom built.
I always found it strange how datasheets are distributed over random websites and ftp servers usually covered in watermarks and could go offline at any time. Is there any effort at archiving and distributing these pdfs?
In addition to the archiving challenge, just the fact that PDFs are the de facto standard in distributing datasheets makes it very challenging to build knowledge bases like FindChips since it is so unfriendly to parse. There is a huge amount of data variety in these documents in terms of structure, formatting, and language.
For whatever reason footprints, pinouts, and dimensions have been distributed via pdfs as the de facto standard, leading to a bunch of wasted work as people have to create their own foot prints, symbols, and 3d models over and over again.
It might seem wasted, but the reality is that a “standard” footprint does not really make sense. Soldering and assembly is not a perfect craft and it requires hundreds of considerations to methods used, environment of use, desired reliability etc. for example look up the footprint differences for wave soldering compared to hand soldering. For aerospace use reliability is king, for mobile devices space is a premium.
Furthermore, there aren’t really any standards for packages and hence it is difficult to trust foorprints. A TSOP package from one manufacturer manufacturer is not necessarily the same as a TSOP package from another. This is not a hypothetical — I’ve been bitten by this.
There are tools to assist in and automate a lot of this, but since most of the time is spend on other parts of a product it simply isn’t very critical.
A standard footprint might not make sense, but a standard format for distributing component pad placement definitely does. Most ECAD systems already have tools in place to generate proper landing pad offsets from footprint.
And you're right that one can never fully trust downloaded libraries, but a lot of the issues could be mitigated if manufacturers distributed their own files. TI does this for most of their devices and it's a big draw for a lazy designer like me.
I'm really surprised there isn't a better solution in the industry - building a library might not take as much time as the rest of electrical design work but it's still a large sink, to where many teams (even as small as 6 engineers or so) result to hiring a full time "librarian" to manage footprints and component libraries.
While manufacturer's may have very small deviations in their footprints, by and large almost every IC conforms to some kind of JEDEC compliant package. From there, IPC-7351B [1] has mathematical recommendations on footprints ranging from Class 1 (minimum required) to Class 3 A/B (ultra-reliable). Obviously those are just suggestions, but manufacturers have been aligning more and more with them. My daily ECAD/EDA tool is Altium, and I can't remember I had to manually make an IC footprint. I use their IPC Wizard[2] to make it all for me. As a bonus, I get a nice STEP model too with my export.
A lot of good stuff has begun to happen in this regard. At least KiCad has a large and pretty decent quality collection of footprints; I think other tools are making similar efforts.
However, I wish they would make it easy to adjust these footprints or make derivatives of them, without having to essentially redraw them.
For a looong time I’ve wanted to apply geometric constraint solving to drawing footprints. This would allow for having a base footprint which defines the constraints and then parameter files could introduce the specific dimensions needed. I’ve been working on it at https://github.com/henrikh/footwork-ecad and the parts are there, but I’d love to collaborate on it with someone :-)
>> For aerospace use reliability is king, for mobile devices space is a premium.
That's a great point. But how many different footprints need to exist for a 1206 led package from one manufacturer? Infinity? Or is it something more like 5?
>> A TSOP package from one manufacturer manufacturer is not necessarily the same as a TSOP package from another. This is not a hypothetical — I’ve been bitten by this.
But that's a different issue of a manufacturer not conforming to the spec they've published for their product. Same as a carabiner failing at a load of 100kg when it's rated for 500kg.
>> But that's a different issue of a manufacturer not conforming to the spec they've published for their product. Same as a carabiner failing at a load of 100kg when it's rated for 500kg.
Package names are, in some fashion, marketing and branding. The manufacturers publish their own specs and do adhere to them. There are also standards (mentioned in other comments), but they are typically more general.
I’m not saying this is ideal – but that is simply the reality.
> A TSOP package from one manufacturer manufacturer is not necessarily the same as a TSOP package from another.
Yeah, I've noticed this too. I now have to check the specific measurements (pin pitch etc) in the datasheets before buying, regardless of what the product page states about packages. I still on occasion make mistakes and get super tiny packages that I can't use without a pick and place machine...
This is mostly caused by both manufacturers and footprint library authors/EDA vendors using their own nomenclature for packages instead of the JEDEC standard names. This is especially apparent with gullwing SMD packages (anything from SO(IC) to LQFP) which are mostly same across manufacturers but vary widely in what they are called.
This is exactly the industry-problem SamacSys are trying to solve with their ECAD content (Symbols / Footprints / 3D Models). They are independent and offer their ECAD Models unlimited for free to Engineers. All the leading EDA formats are supported like KiCAD, Eagle. Their website (ComponentSearchEngine.com) where you can download the content also offers builder tools and a free fast turn around request service, so you can get models for almost every part you want quickly even if its new. SamacSys are distributing their ECAD Models to Findchips.com, Mouser, RS etc and behind all the leading EDA tool companies like Mentor, Zuken etc. Currently over 15,000,000 parts have CAD models. Hopefully this industry challenge is finally solved! - full disclosure i have worked with SamacSys, hence having the knowledge but they are really about fixing this problem for engineers so wanted to comment.
My friend and I built a project to see how much we could automate symbol and footprint generation from drawings. We got busy and never polished it off, but it’s avalible at https://pinpoint.parts in case anyone wants to try.
Sorry in advance, I just noticed our cert expired (I thought we set up automatic rotation, hmm..)
Within my domain of expertise (space engineering), the problem is even worse. Not only do suppliers provide haphazard information about parts through PDF documents, there's very little, if any, real convergence on what to actually provide to the engineer.
I'm confident that these highly unstructured PDF datasheets are going to go the way of the dinosaurs, but it's quite challenging to integrate any smarter solutions into the business chain.
My domain of expertise is the space industry, and it's stunning how much of a mess datasheets are. As an engineer on different missions, I couldn't understand why I was spending so much time trying to "undo" all of the work the suppliers had done to create these documents, to be able to get the data into into the tools that I needed to use and actually start my real work.
In the space industry at least, there's a concerted effort going on to try to replace these PDF documents with electronic, machine-readable equivalents. Through the European Cooperation for Space Standardization (ECSS) [1] and work being done by agencies like ESA [2], and private industry [3], but really it's not yet taking hold for a lot of operational reasons.
We're actually working on trying to digitalize the entire global supply chain by converting PDF datasheets into something that allows more intelligent engineering work. We're currently serving "level-1" through our website: https://satsearch.co.
We've also prototyped a way to cast the datasheets into something more usable with ESA and a number of other partners. We've currently serving this digitalized data through our API: https://api.satsearch.co, which is being integrated into industry tools.
The real dream for me is to get to the point where the engineer can work with this kinda data natively within their tools and skip the entire PDF datasheet fiasco. Ideally, the data can then even be operated on my multi-objective optimization algos to speed up the entire design process.
Disclaimer: I'm one of the co-founders at satsearch and we started our startup precisely because I was just sick of dealing with PDF datasheets.
> how datasheets are distributed over random websites and ftp servers usually covered in watermarks and could go offline at any time.
There are simply too many vendors' products on the market, only a handful of vendors have a systematic way of providing searchable datasheets online, like Microchip or ST, others simply come and go, so it's extremely hard to obtain an official one.
Worst are the ones that add protection on their pdfs so I can't highlight and add notes to the datasheet. What are they afraid of? In any case, here's how to bypass that (quoting myself): https://news.ycombinator.com/item?id=16448044
I'm maybe not experienced enough as I only do small electronics projects with a limited set of components which I always use, however, in my limited experience I see typically see datasheets in two places: on the manufacturers website and on the distributors website. For example, if I buy an Microchip EEPROM from Mouser, then the datasheet is typically available both on Mouser's product page and on Microchips documentation page.
Very much so, especially for the types of parts you will find avaliable from the Chinese sites listed. Finding a data sheet for an AVR or a MSP won't be a problem, but finding a data sheet for a super-cheap off brand micro can be a real challenge.
For hobby electronics projects, the only time you may run into this is if you are using recycled components, since datasheets for older parts that aren't current stock may be very hard to find.
I don't know if there's a centralised one (and I'm keen to find out!) but this is why I always save a copy of any datasheet I find at first opportunity and now I have hundreds, filed by manufacturer.
I usually look up chip names while cracking open electronics to fix issues. The chips could be 5+ years old by then and it seems like its only by chance that some random website has a copy of the datasheet hosted.
If only sites like this existed when I was doing design work. Really looks quite helpful to have a distributor agnostic site. Not sure about whether the popularity metrics are useful, you might end up using popular chips in the same way you end up with a lot of 10k resistors (old argument that all component values should be calculated and thought about).
Findchips is amazing. They visited our company last year and pitched their software. I gathered a small audience and we learned about what they have to offer. We subscribed and it became immediately apparent their service is essential. In a market with so much allocation, finding stock on parts is made easy with their channel analysis. This is one of the few subscriptions I've ever really felt was fully justified.
FindChips
Oemstrade
Octopart
Chip index
These are all a decade old and easy to find.
I try not to be cynical but if you are trying to source components either as a hobbyist or procurement professional and ARE NOT using one of these easily found sites then you are getting goosed.
> if you are trying to source components either as a hobbyist ... and ARE NOT using one of these easily found sites then you are getting goosed.
Maybe, but my volume is so low and orders so infrequent, it doesn't really matter if I pay $1 for an IC or $0.5, so I usually just go with what either is the most convenient (eg sparkfun breakout boards) or the quickest shipping (Farnell has free next day delivery for me). Having said that, these sites are great resources and I do check every now and again.
It's nice, but it doesn't tell me all that much I can't get from other sources like Octopart
What does "parts popularity" mean, anyway? You probably don't have sales volume. Number of distributors? Part popularity is actually useful; you want to design using popular parts when possible, to avoid supply problems. Seeed Studio is big on that; that's why they have a recommended parts list of parts they can easily get in Shenzhen.
> you want to design using popular parts when possible, to avoid supply problems.
How does this design strategy actually avoid supply problems, e.g. when a component manufacturer issues EOL notice, what stops professional logistics/procurement staff at Big Fish Corp--whose design activities were likely responsible for the supply glut to begin with--from pushing lifetime buys to ensure sustainment of their product line, instantly draining global authorized distributor stock overnight?
yes, EOL's and ECN's pop-up a lot. Sometimes it's nothing (a pin-compatible alternative exists), sometimes it's a nightmare requiring a design change.
At my work, we have seats with SiliconExpert, this is a tool that you can use to get availability "risk assessments" for your BOM among other things like RoHS stuff and conflict minerals status.
I've never seen an "overnight global supply draining" occur for a part. There are distributors that make a living buying up millions of components throughout their lifecycle and then sell them for ~20X their cost (or higher) when the part goes EOL. It might be annoying, but these vendors can keep you going until a suitable replacement is located, designed-in, qualified and rolled out to production.
Professionally, a much more important question is how can I trust this data? Any perceived convenience in data aggregation strikes me as all for naught if specific details will require corroboration from the horse's mouth anyways before having sufficient confidence to make a design/procurement decision. Otherwise, it's a nice resource to leverage if its inherent risks are within your comfort zone.
In my experience the reason why one learns expensive lesson (happened to me also and it was the only case when I had to respin board due to wrong footprint) is that you just end up thinking "this is too simple to get wrong".
I had my share of shipped products with extensive manual rework, professionally made bodge boards and respins of 3ft square boards (which there were enough that the board does not use letters for revisions, but timestamps of when the gerbers were exported), but it usually involved questionable component choices and attempts to route what should be controlled impedance diffpair across 10s of centimeters of two layer board and cheapest connectors we could get, but really the only case of respin due to wrong footprint involved measly BC840 NPN transistor with rotated pinout... (on the other hand hand soldering the transistor involved at the 45deg angle solved the issue for first batch which was hand assembled anyway :))
This tool seems to have similar information as Silicon Expert - which is pretty expensive but has a nice system where you plug in your BOM and it gives you the part risk, RoHS status, and possible alternatives if available.
Risk in this context is how likely the part will go out of stock or "end of life"-ed. If a part has no alternatives it is even more risky!
When I designed a large board oftentimes several of the tiny parts such as capacitors or resistors would go out of stock but this generally is not a problem if you are using a common part. If you have a good contract manufacturer you can flag any parts like these as "use equivalent OK" and they will automatically pick a new part for you if necessary, with the same or better ratings.
Some companies also use their own internal part numbers for each electronic component (like a 10k 0805 resistor will be part AB1235) so then they can map that AB1235 part number to a list of acceptable manufacturer part numbers. That seems like too much work for me though!
Nice site. By the way, does anyone know the easiest way to get points to download datasheets off CSDN? Using chinese services internationally is so hard...
www.icgoo.net
www.ickey.cn
www.hqew.com
www.szlcsc.com
And for more international parts (still used in mainland a lot)
www.eciaauthorized.com
Octopart is a more generic site for discovering chips and getting an idea of the price, but still it fetches crappy prices from Digikey, Farnell, Mouser, etc.
If your product is being made in China and you are making the design choices, a quick Taobao search (or using the above links) is great to see how popular a part is. Not recommending to buy parts from Taobao though (unless you are more seasoned). There are also alot of agents that can source parts maybe 1-2 levels below the original factory. Their prices are so good it's unbelievable but they are hard to find and validate. Having volume also helps.