# Parts shortage, no stock, what now? (canonical reference question)

As a small business, student, or hobbyist, sometimes the parts I need are unavailable (no stock anywhere). Maybe authorized distributor will take order but they will not ship for 10, 20, 30 weeks, which is a very long time to wait. If I search on internet there are some marketplace or auction sites that seem to have a few leftover parts, but I don't know how reliable they would be. If I buy bad parts that's a waste of my time and money, but if I buy only from authorized distributor, I can't get parts until 6 months or a year. Why is this happening? What do I do?

-- inspired by Source microcontrollers in this difficult times

Note this is a self-answered question, intended as a canonical reference question. Other answers are welcome.

• Not mention specific manufacturers or distributors.
• Use facts, not just speculation or opinion.
• Be applicable two or three years from now, not just today.

Meta discussion about whether this question is on-topic: Canonical parts-shortage question?

• This used to happen regularly in the 1980s, kind of the pioneering microprocessor days, when things suddenly went viral and instantly sold out. It was almost an annual cycle when the new gen of (4x bigger) memories came out. The Covid business cycle is almost giving the old hands nostalgia... Jul 30, 2021 at 20:12
• I once had hundreds of uC that my Disti Rep was begging for some to give to another major client. Jul 30, 2021 at 20:17
• Great question/answer, thanks for posting it. Jul 31, 2021 at 4:01
• If I search on internet there are some marketplace or auction sites that seem to have a few leftover parts, but I don't know how reliable they would be. Assuming everyone else is sold out, you just have to try these smaller marketplaces and see how it goes. Personally I tried such marketplaces twice and got good parts both times. However, one of them was so slow to ship that the part was back in stock on digi-key the day it arrived (the small distributor shipped it to the US by China Post or something silly like that). So always ask for express shipping with a major carrier like DHL. May 25 at 20:16

I work at a major analog IC manufacturer since 1990, and I have seen these kind of supply shortage cycles. These cycles come and they go, like the weather.

From an IC manufacturer's perspective, the problem is that manufacturing a complex IC requires a long lead-time, so product-line managers have to estimate in advance what will be needed. Large customers sign long-term sales agreements to secure their supply during the crunch times, so it's straightforward to plan to support these customers. But a substantial amount of business is small and medium-sized business customers who place "turns" orders to ship in the same fiscal quarter, essentially a demand for immediate shipment. If there's work-in-progress or inventory, that can be used to satisfy "turns" demand. Planning is hard, especially when most of your customers never talk to you except when they want parts immediately.

If there is sustained demand for more parts, then the long-term response is to build more manufacturing capacity. That requires substantial investment and time to bring up a new fab. Usually there are long-term 5-10 year business plans that call for building new and improved fabs, and shutting down obsolete fabs, so at this level the expanded manufacturing capacity eventually breaks the shortages. But the risk is that if the demand wasn't real, then the company loses money on the fab or goes out of business.

Whenever demand exceeds capacity, there are shortages; and "turns" customers tend to respond to shortages by placing multiple orders for the same line item (like ordering LM7805X, LM7805Y, LM7805Z, when the customer only needs any one of those) and then the customer cancels most of these orders as soon as they take delivery of one of those parts. The worse the shortages get, the more the small and medium-sized business customers place multiple panic "turns" orders that will later be cancelled, and the IC manufacturer business managers notice this and start to disregard the "turns" business as unreliable. They'll build more capacity if a big customer makes a long-term commitment in writing, but they won't build more capacity to satisfy orders that they expect will be cancelled.

I can always tell when we are in a global supply shortage storm when I start to get a lot of customer support calls asking for exact replacements of our own products, of the form, "do you have a second source for (your company's) XYZ123". Our company doesn't re-design an existing product and release it with a different part number, that doesn't make sense; but desperate customers dream that somewhere there's a box of XYZ123a that are just as good and nobody else has thought to use those. Sometimes though there may be multiple grades of similar product, with differences in temperature range, accuracy, maximum speed, or supported features, sometimes even in the same package style; so it's not a complete nonsense inquiry -- reading the datasheets and product selector guides, together with an understanding of the actual customer requirements, can often find possible alternative parts.

Another force that contributes to the problem is that financial analysts (wall street) strongly dislike excess inventory. The popular Just-In-Time logistics planning used in the automotive industry and other businesses, comes from this financial incentive to aggressively minimize local inventory. The idea of Just-In-Time is that the delivery truck arrives at the receiving dock with more supplies just as the local parts supply runs out. When it works, it lets a customer factory work efficiently with most of the floor space dedicated to assembly and testing, and very little floor space dedicated to storing parts and supplies. However the risk of Just-In-Time is that any disruption in the supply chain directly impacts the factory operation.

Counterfeit products such as engineering samples, old revisions, failed test reject units, and even unrelated parts with similar packaging, are easily re-inked with whatever top markings will sell this junk to the most desperate customers, who don't have the time or energy to fight a $25 or$50 loss, and it's easy enough for these fly-by-night cheaters to create a new account if they start getting bad reviews. There is even a scam called "brushing" where a dishonest auction vendor creates fake reviews to give the appearance of being a trustworthy source. There's an old saying that if a deal seems to good to be true, it is; and in times of global parts shortages, the "too good to be true" element is that the parts are available. Buying from these type of auction sites instead of authorized distributors is gambling that you're not being sold a bag of sand.

So for a small or medium-sized business customer, the problem is how to defend yourself against these supply chain troubles, where the parts you want are "on allocation", none of the authorized distributors can supply you any parts except with 26-week lead-time, and the only place you can find what you need is on the gray market...

The first step is to recognize that there is a "storm" of high demand currently squeezing the supply chain, so you cannot simply buy whatever you need just-in-time, at least not until the supply chain recovers and becomes more stable.

If you're a small business and you know you need to build 1000 pieces, then you have to find 1000 or more pieces of something you could use, and get those parts in-hand. If you can't get the parts, you can't build product. For a hobbyist, that could mean delaying a project; for a very small business, it might make sense to go into hiatus until things clear up. At any rate, in such times you have to deal with the supply chain issue hand-in-hand with product design. You can't ship what you can't build.

Relationships are important at times like these. If you are trying to get microcontroller XYZ and the datasheet lists 12 different ordering numbers, examine the ordering information table in the datasheet, and determine which exact part numbers you might be able to use. Maybe some of the parts have insufficient memory or speed or voltage or package size. But maybe there are 5 different ordering numbers that would all be usable in your application. Contact a person at an authorized distributor, either chat or DM or voice phone call. For example, "Can you help me find 1000 pieces of microcontroller XYZ, I can use any of these 5 ordering numbers" -- maybe you can even accept mixed lots or partial reels, 300 of XYZa in 3 weeks, 500 of XYZb in 7 weeks, and 200 of XYZd in 2 weeks. These are challenging times for the distributors too, so if you can offer them some flexibility about what parts you can accept and when you can take delivery, they may be able to negotiate something.

Contract Manufacturers (CM) are another possible resource for helping with supply chain issues: there are many companies that encompass both PCB fabrication and assembly. Customers can send the PCB layout files and bill of materials, and the contract manufacturer fabricates the PCB, sources the components, and assembles the boards. Often the CM can even perform some level of testing. They may have an internal inventory of "partial reels" of commonly used components like 0.1uF capacitors. They might also have relationships with distributors and manufacturers. Call a CM salesperson and ask for a quote, they may be able to work something out. CM assembly quotes tend to be a premium price, but they do encompass a larger scope of work that just providing blank boards.

At some point the microcontroller might become so much of an uncertain element due to supply chain issues, that it makes sense to design to support multiple alternative hardware options. Ordering blank PCBs is not too expensive, so if you design one version of your product's PCB that is based on ARM and another version of your PCB based on PIC and another based on STM32, with the same mounting holes and same connectors, then you have even greater flexibility against supply chain problems. The cost is that now your firmware has to support more than one target, and that gets complicated. If your firmware is written in C or some similar high-level language, there's a good chance you can make your firmware portable between the different microcontrollers. If you really don't know from week to week which microcontroller you can buy, then writing portable firmware and supporting multiple PCB options becomes worthwhile. Sometimes PC motherboards can be seen that are shipped with "empty" locations, because the successful motherboard vendors already use this technique to defend themselves against supply-chain disruption.

• Rather than ARM, PIC, STM32, maybe keep it all ARM but from different families (STM32 being one of them) Jul 30, 2021 at 20:17
• This was the issue that convinced me to do my own business. I think what you are saying here is great, it just so much easier if people just communicated. I once got a call from a CM saying they could not make my board because of error -47. All I had to do was call and get the assembly operator. He was new and the expert was out, and all I had to do was walk him through the awful software on his machine. It is so easy, yet this is rocket science to so many.
– Bill
Aug 4, 2021 at 17:08
• Planning is hard, especially when most of your customers never talk to you except when they want parts immediately. You mean you don't listen to small customers until they go through all of the red tape to create an account on your complex webpage. May 25 at 20:00
• placing multiple orders for the same line item (like ordering LM7805X, LM7805Y, LM7805Z, when the customer only needs any one of those) You describe that as "panic". But it's not panic. It's simply not having the information about which part variant the manufacturer is actually planning to make. Manufacturers can solve this by obsoleting part numbers for variants they're not actually planning to make. Or at least providing better hints on digi-key than just saying everything is 52 week lead time. May 25 at 20:09

I'm answering as a circuit designer facing the supply challenges of 2021 when trying to use high-specification silicon carbide transistors

What do I do?

I've been facing supply problems for a design I'm involved with for three months now. It uses 1,700 volt SiC MOSFETs and the delivery dates seem to lengthen each and every week. For instance, the original device I chose suddenly became unavailable until mid 2022. There is a very similar part in a regular 3 pin TO-247 package so, I placed orders that were initially given a delivery date of June 4th this year. This was to prove a pipe-dream and, week-by-week, that delivery date drifted until it is now somewhere in 2022 (like the original part) so, as a designer I had to fight a little clever. This meant the path I had to take spawned several new routes: -

• Redesigning the circuit to work with 1,200 volt SiC MOSFETs at a slightly reduced output specification.
• Agreeing with the customer that trials with a 1,200 volt MOSFET was good enough for what they want for the next year or so. It also proves the design concept.
• Making sure that a good range of available 1,200 volt devices could all be driven using various swappable parts that could generate the applicable drive voltage for the particular MOSFET that I might have to use.
• Recognize that high-isolation-voltage DC-to-DC converters were now proving difficult to get (another supply problem) so, you take the opportunity of buying future stock for what you know you might need as early as you can.
• Redesign (plan B) using a totally different switching technology and this is progressing nicely (should things get bad in 2022).

In other words, I designed the PCB to be diverse; it could be reconfigured for various different sources of MOSFETs. As a designer, it seems that 2021 is a water-shed in how you face-up to your responsibilities. It's probably made worse by Covid AND the sudden demand for high voltage SiC MOSFETs in the automotive and energy industries (a bit of a perfect storm).

BUT, I have a back-up plan (should things get bad in 2022) that doesn't rely on SiC MOSFETs. Not as elegant but will work.

• “if you recognize what is happening, you take the opportunity of buying future stock.” I think everyone does this — and understandably so — but it is reinforcing the shortage. Jul 31, 2021 at 11:16
• Not true. Placing orders to secure future orders is a way of signalling to the supply chain what their overall requirements are going to be on such and such a date. Expecting to order something and get it the next day (and being disappointed) is causing the perception of a shortage and thus propagating a panic buy @Michael Jul 31, 2021 at 11:43
• Oooh! Is it you who are stealing the 1700 V MOSFETs from me? IXYS and Cree won’t talk to me anymore. May 25 at 20:10
• Not me dear @winny - I can only get hold of 1200 volt types unless I wanted to buy the really crummy ones from Genesic (been there and blown 'em up). Luckily I can just about get away with 1200 volts as the application has a max voltage of 900 volts. May 25 at 20:16
• Oooh2! The Genesic performed excellent in all my tests. Which one failed on you? May 25 at 21:24

I had worked for 40 yrs on all sides of component choices as a designer to Ops Mgr of SMT R&D responsible for all aspects of purchasing, stock picks, and order management to eng mgr for a major Contract Manufacturer for PCA’s and even worked with “schlocker hard-to-find part” disti’s that gouge you on prices but get large orders in short times.

Your best bet is to choose the best equivalent part in stock from a major Disti like Digikey, Mouser etc. They ship same day if in stock and orders placed before a set time.

The onus is on your design expertise to choose equivalent or better parts.

If you need uncommon parts, there must be a good reason and you are at the risk of choosing sources that you may have no experience with, good luck. They may take RMA’s for malfunction if you ask.

Major cities will have small suppliers that charge more like Sayal’s in Toronto with 3 stores. But they have a decent selection of everything that hobbyists use.

• I am really struggling to even design around optional parts. Sure, for diodes, passives and such, perhaps transistors.. But the real problem is DC/DC converters, and more specialized IC's. I have never been able to design for equivalents, as there are very few that are pin compatible. Aug 9, 2021 at 12:19
• When no equivalents exist, it’s time for cuts and jumpers or a new design / layout. FWIW @Arcatus Aug 9, 2021 at 12:41

As a hobbyist/student, you are stuck with the stock that common suppliers have. You can buy demo or hobby boards and remove parts if you're hard up.

As a company, it is very important to have a face-to-face relationship with distributors and manufacturer field applications engineers (FAE). The FAEs of various IC companies have gotten us out of short term supply problems. You normally work with distributors so you have parts reserved for the future which means you need to plan a year or two in advance. Planning can also reduce component prices. FAEs can get you parts for prototypes, usually gratis. Interpersonal relationships are very important in business.

The one thing you don't want to do is buy from shady distributors. The chance of getting counterfeit, wrongly marked parts, repackaged parts, and parts from the reject bin is much higher than going through an authorized distributor.

Just spent last 2 weeks scrambling to secure 2 years' supply for what should be very ordinary BOM's that were 100% stock until now, but came in with 52+ week estimates for some parts.

Part of the problem was knowing whether to trust a "16 week estimate" for a substitute (answer: not without verification).

Things I've learned or done

1. Use an inventory-comparison tool like Octopart, to strategize on substitutions. But beware/verify the no-name distributors, who sometimes report fake numbers of inventory to the comparison-shopping services.
2. Ask the usual distributor (e.g. Digi-key/ Mouser/ Newark/ Arrow for me in the US) to refresh their factory lead times and delivery estimates on back-orders due longer than a month out. When a factory lead time is extended (ie delayed) in circumstances like now, this update to the vendor, in more than a few cases, did not happen automatically. But if asked, the vendor was able to "pull" the info rather than waiting for manufacturer to "push" it. Be nice though, they are seriously slammed - Digikey reps reported 2x increase in volume this year (!).
3. Design change... sometimes is better than getting shut down for lack of a diode array or something.
4. If truly stuck, and application has future potential or is strategic to manufacturer in some way, reach out to national sales office for the manufacturer. Some can help, some can't. Also can be useful to get a feel for where manufacturers and countries of origin are relative to each other.
• For EU, just substitute Farnell for Newark. I'd also throw in TME - the biggest distributor in Poland, they ship worldwide. That's for the online distribution. Aug 1, 2021 at 14:19
• Yep, Farnell UK (or EU area generally) is a great resource, even coming from North America!. Aug 6, 2021 at 1:29

Coming from a background of engineering management, component approval and general component hunting.

The component shortage crises are only getting worse and worse. This is caused by many things, some notable factors are the "just in time" mentality and more automated purchasing systems. In big companies, the purchaser typically just gets a message from their business system: "we are out of x, buy more x". So they place an order for "more x" and when there's a shortage, they then get the 52+ weeks (a.k.a the middle finger) from the component vendor. After which the purchaser panics and places larger orders, making the shortage even worse. And they also place more orders on the products where that part is present, causing a "whiplash effect". Contract manufacturers paradoxically get a lot more work during a crisis because of everyone panicking and placing extra orders of everything. As the cherry on top you have speculative component traders looking for these shortages and buying up stock everywhere.

The issue of component shortage lands somewhere between the R&D team and the purchasing team. Both need to do their homework in advance: when the crisis hits and you can't get any parts, it is already too late. You need to already have pre-emptive routines present in your organization to soften the blow. You learn this with experience:

• When specifying a part, activate some purchasers and have them investigate if it is viable. Engineers is notoriously bad at this: we tend to only look at the technical specification and maybe price, but not "boring non-technical" things like part status, lead time and general availability.

• Always specify a second source if possible, at the point where you specify a new component. Similarly, engineers hate this because it is "boring" - they already found the part that fills the specification, right?

• If 2nd source is not possible, then at least try to not specify too exotic parts. Check with someone who knows the market if your component is a "high runner" - that is, something that a lot of different customers buy. If you just specify some random part you found on the web, then it might be one that it is one which the silicon vendor only has one big customer for. When that customer stops buying the part, you are in trouble. You can often ask a Field Application Engineer (FAE) about such. Also check the Minimum Order Quantity (MOQ). A large one might indicate that the part isn't intended for small- to medium-sized customers.

• Overall it might be better to use several standard parts than a single "monolith"/SoC etc with everything in one chip. You get a bigger BoM but you don't necessarily get stuck with one single manufacturer. And re-design might become less painful.

• Cost isn't everything, it is sound to specify parts from well-known vendors which you have a good history with. Do they have good tech support, do they have good sales support, how did they treat you during the last crisis?

• Check with the manufacturer if they have "longlivety" guarantees. In case they guarantee that a part is available, then that also means they will at least have stable production of a part over a longer time period.

• Make sure to register on part status mailing lists, so that you get "PCN" (Part Change Notifications) and "LTB" (Last Time Buy) messages. (Beware of "component print" change spam - might want to have a company-wide e-mail where these notifications land.) After a part goes obsolete, there's often replacement suggestions by the manufacturer, but it might also be an indication that a design update is in order.

• When you get the mentioned 52+ weeks middle finger, make sure to note which vendor you got it from and avoid that vendor in the future. Some silicon vendors are notoriously bad at providing stable lead times. I won't point any fingers here, but in the long term you'll benefit from keeping a blacklist of certain vendors, no matter how good or cheap their parts are.

Also beware of creative excuses in times of crisis. There tend to be a lot of "we had fire in the factory" etc excuses in such times when the vendor is just trying to stall and buy time.

• In case you buy from a component vendor rather than the manufacturer directly, then ensure that the vendor is actually keeping parts in stock. Otherwise they are likely just waste of space middle man, taking your money but providing nothing in return. You should then investigate if it's possible to buy the part directly, or from some better vendor who keeps parts in stock.

• "Just in time" evidently doesn't work well in the real world. You need to keep your own buffer inventory of key components. Microcontrollers & other "intelligent" parts in particular.

When the crisis hits, then there isn't much you can do but to wait it out, re-design or buy from shady "spot market" component traders (big chance of fake parts or silicon dummies).

• -How can I get hold of someone that "knows the marked" when I am selecting parts? We could probably even hire a consultant for a some hours for BOM advice, but even the largest national consultant companies have virtually no useful input on this. The typical reply I get from experienced consultants start with "Back in the day we used to solder our own transistors... or whatever - witch is irrelevant when I try to select a modern mosfet. - What mailing-lists? I probably have a dozen or three of those, and every single one of them are advertisements. I don't think that I ever gotten a LTB. Aug 9, 2021 at 18:35
• @Arcatus As I wrote further down in that same bullet, you could contact an FAE working the silicon vendor or the retailer. As for PCN/LTB notifications, any serious vendor registers your purchases and sends you a PCN when parts change. Avnet, Arrow etc. It may be that these notifications end up with whoever placed the order. If you only buy from "catalogue companies" (Digikey, Mouser etc) then I don't think they do this - instead they display the part status on their site when you view the item before placing the order. Aug 10, 2021 at 6:38
• Silly question, I guess; But how can I tell that Arrow is a serious vendor, while Digikey is a "catalogue company"? To me they look identical. I have used digikey for years and have no complaints there. (other than the missing PCN's, apparently) Regarding FAE they typically stop replying when we estimate a consumption of some hundreds parts, annually - we are not worth their time. To me that option seems unavailable to any small and niche company. Aug 10, 2021 at 20:04
• @Arcatus Before Internet shopping became the mainstream thing, certain kind of vendors sent out paper catalogues to their customers. These kind of "catalouge" vendors aimed for low volume customers that needed fast delivery. Which in turn meant limited stock of rare parts and higher prices. Whereas Arrow, Avnet and similar aimed for the high volume customers and therefore kept more stock, bigger sortiment, lower prices but much longer deliveries. -> Aug 11, 2021 at 6:21
• It's more of a blur between these two business models nowadays, mainly because silicon vendors more often sell parts directly to the customer. But also because those who previously aimed for high volume customers stopped keeping parts in stock to save cash, and sacked their own tech support to save cash. Avnet seems to be a rapidly dying company for example, where they used to be the biggest one. Aug 11, 2021 at 6:22

I have noticed two drastic changes in my workflow compared to <2020:

1. I used to do: Simulate, Schematic, Layout, Order. Now I do Simulate, Check stock, Order, then only start on the project schematic and layout. This involves creating stocks of items which unfortunately amplifies the main chip crisis but keeps me working.

2. I try to avoid proprietary parts whenever possible. This also helps with stocking because I only need fewer general parts instead of 200 different proprietary ones. I do a lot of analog design. I make a lot of circuits (opamps, linear and switching regulators, references, buffers) with discrete parts now. It has taught me a lot about the inner workings of these parts, up to the point that I can confidently fulfil even special requirements that aren't available in integrated parts. The design has become much cheaper because dual npn, dual pnp etc. chips cost next to nothing. Even assembly becomes mostly cheaper, because although there are more components on the board, there are fewer unique components, which is easier to place for automated PnP.

Large scale integration chips are still a problem though. I try to minimize these in favor of one large processor/FPGA and try to obtain supply agreements for those.

I feel the same. Our company is a small-scale company, which undertakes the manufacture of various electronic products. Since last year, there has been a serious shortage of materials. When we buy parts from famous distributors, we are often told that they are delayed or out of stock.

Other ways：

1. Component replacement
2. Modify PCB design scheme

Pay attention to how different manufacturers manage the shortage, and go with manufacturers with more reasonable behaviors.

For example, many manufacturers will pretend like there is no shortage; they just sell out all their stock and then suddenly there is no stock and huge lead time. Then you can buy their parts for 25X the normal price from countries that allow shortage stocking (not the U.S., apparently... so if you live in the U.S. you have to factor in shipping from China).

While other manufacturers manage the situation carefully. They create new part numbers with temporary shortage pricing, so you can still get critical parts for a reasonable price (2-3X normal) during a shortage.

Some manufacturers even manage to get lead times under 52 weeks during Covid, which is awesome. Unfortunately, it does not appear that digi-key currently allows searching based on lead times. So you have to sift through the results manually.

• Parametric search based on estimated delivery date is seriously missing from mouser/digikey. that's despite the availability of this information on the product pages May 26 at 7:14