Component sourcing and Mouser vs. Digikey Pros and Cons

This post is about mainly sharing the experience of a small maker business sourcing genuine components right here in the USA. Sourcing and stocking the right components in the right quantities is one of the finest balancing acts in a small electronic manufacturing business. That’s because keeping large stocks of parts has not only tax implications but also drains funds from other efforts faster than you may realize. If you’re a beginner and need some tips, here’s some experience that might save you a little sweat and hopefully a few of your hard earned dollars. I might will update this article in the future as more things come to be realized in this area of the business.

My main parts suppliers since LowPowerLab‘s inception were Mouser and Digikey. Both are great in their ways which I outline down below, but there have been some surprising downside quirks as well. Hey it’s a little hard to get motivated to write only about awesome things, usually the bad stuff triggers reviews. But I’ll try to keep this objective and informative. If both were great at everything then there would be no reason for competition or even having multiple suppliers. Monopoly is a bad thing in supply chains, and I hope these companies will continue to exist as separate entities and not eat each other in some monster acquisition deal.


I have mainly 2 types of orders. One type is the “small value” prototyping batch of components or small run custom batch for a client which I usually place at Digikey due to their more comprehensive offering. Even this can run into the lower hundred dollar range depending on the project I’m putting together, but the average is under $100. Then there is my normal run, what I call the periodic replenishing orders which are in the thousands of dollars range. Whenever I run low on certain parts, I place them in the cart, and they stay there until I’m ready to complete the order. It’s unlikely for me to use fast shipping, so I usually go with ground services. I even use USPS for the real low count prototype orders.

Before I get into my sourcing experience with these suppliers, let’s take a quick look at the pretty incredible state of affairs with respect to passive component sourcing in Q1/2018. So as a quick primer side story about parts sourcing – if you’re a maker you’re already familiar with the astronomical passives lead-time situation. Just the other day I was scrambling to find 0.1uF 0603 caps (which along with 0603 1K 10K resistors are the most popular and numerous parts in my designs). They  nowhere to be found these days due to extreme factory lead times for new passive stocks. I ended up paying $210 this week for the last 15K reel of cheapest 0.1uF caps (normally <$20 for a 4K reel). Yup, it’s that bad!

Neither of these companies are directly at fault for this, at least not for the supply chain. But they control their dwindling stocks pricing of course that’s for sure, and why not make a buck while in this dire straits, right? This week I made the mistake of keeping some reels of basic passives in the cart for a day or so until I completed my order (at Digikey first then at Mouser when Digikey 1) doubled the price then 2) went from a comfortable 16-24,000 parts to 0 stock. No problem, Mouser doesn’t mess with pricing right? Then Mouser did it too, but too late for screenshots to prove it! I should have just bought those on the spot knowing everyone else is trying to buy them too. Don’t procrastinate silly!

Anyway let’s now go ahead and imagine a little fable here:

In general as companies (not necessarily these) get larger they tend to become more imperialistic, trusting their dominance on market share confidence and getting preferential with customers depending on their bottom line impact. Small customer care becomes secondary. Me and you are probably lost in the background noise of annoying small customers, more so the lower the order value (more overhead per order for less profit!). Say you bought a few different SMD resistors, some switches, whatever else small value components for your latest breadboard project.

You buy not-overnight shipping, place your order sometime in the morning and expect them shipped in cut tape or whatever part spec packaging, before the same-day shipping 8-9PM cutoff time, well in time to get it for your exciting weekend project you’ve been looking forward to. But hey wait – who cares about your $19 order value, when there’s real customers. Think someone will walk the warehouse 5 minutes to count and cut your 10x 0603 resistor tape then pack your $19 order by cutoff time just because your order came in early? Have a question or concern? Go away annoying fruit fly, we are having some difficulties fulfilling the unexpectedly large number of orders in the last day, we will get to your order after the real customers and our interests get served.

That fable is a little on the extreme. But it get’s pretty close to reality actually when it feels like it’s happening to you, again, then again, and again.


Let’s look at the pros and cons which I’ve seen in the past few years of dealing with these suppliers.

The goods:

  • Digikey has an awesome parametric search which helps searching for a specific part in a specific packaging, in a specific quantity, and very quickly. This is my go-to tool to decide on a part in a new design, find alternatives, and get a feeling for the available stocks in the foreseeable future. Picking components can be like brain surgery, and Digikey gives you the right scalpel to do it.
  • Digikey has a huge inventory, I think partly because it’s all in a single worldwide location in Thief River Fall MN, USA. If someone else doesn’t have it, Digikey likely does
  • Mouser has been awesome at shipping, always shipped during the claimed timeframe, and often upgrading me to next-day air. More on this when I converge on D&M’s fulfillment and shipping.
  • Mouser has had consistently better pricing in some surprising categories (but not for passives where Digikey is much better). You can get a certain Schottky diode from Digikey for 15¢ in quantity, or 7¢ from Mouser. This happens on $10+ parts too!
  • Digikey’s labels are much better than Mouser’s, they are are easy to read and quickly spot the important ID and counts.
  • Both have smartphone apps, both with glitches and bugs, but sometimes useful when I’m on the go.
  • FREE Digikey shipping to certain/most(?) international destinations for orders over $100-ish – ex. check here for your country

The bads:

  • Digikey has consistently had higher pricing than Mouser irrespective of qty. For passives Digikey is still much better (small ceramic caps, resistors, inductors). If you call them for price-match they make you go through loops to prove it and only certain suppliers like Newark and Arrow are accepted, both of which are pretty useless here in the US. It takes time to get a reply and they denied me a few times because the competitor doesn’t have the part count for the price break I am quoting in-stock. Useless price match.
  • Mouser’s parametric search is marginally OK but a pain to use more extensively, I only found myself using it the past weeks when trying to find some caps and other passives, surely with some mild neuron loss.
  • Mouser’s inventory has been getting better but still lags ages behind Digikey.
  • Digikey is far closer to me than Mouser, yet I always get their packages a day or two later or even more if a weekend is in between (same shipping service). More on this below.
  • When both of these giants go out of stock on some ubiquitous component like atmega328p’s then you’re at the mercy of other smaller suppliers. Sometime’s you may surprisingly find a good deal at Future or some other more obscure supplier you may have never heard of. Otherwise you may try directly at the manufacturer if you’re lucky and there is no lead-time, and ready to buy minimum qty, full trays or so many reels of parts.
  • no free USA shipping regardless of order total, boo Digikey

Digikey vs. Mouser Fulfillment

One of my main components is the venerable atmega328p which I buy in trays of 250x, usually at least 2-4 trays each time. There are expensive $3-6 parts/sensors which I buy as a partial digireel simply because keeping $9000 invested in a full reel is a little scary to me (what if it goes obsolete and the arduino world moves to the new version like it happend with the BMP180 and newer BME280 sensors). When I buy full trays or more than 1000x of any taped component, I expect a reasonable effort to be served full trays and 1 continuous tape of that component rather than several pieces of tape. It’s common sense that these items will be machine placed, not hand placed.

Digikey’s dodgy packaging

Here’s a real repeating scenario. Digikey has been consistently dropping the ball on component packaging and has been sending me “scrap” parts. Instead of a package of 2 full trays (500x), I’ve been getting a full tray + a partial tray + scrap pieces of cut-taped atmegas, packaged separately. So I have to do their job moving parts from tape to trays for use in the pick and place. In doing so I noticed various different date marking on the chips, so they are basically cleaning their parts bins and just dumping it to no-name customer me. Thanks Digikey, your time savings and inventorial efficiency remind me of how much I mean to you every time I sit there with tweezers trying to place each chip in the tray in the right orientation, and flat to prevent pin bending. What a pain. On the flip side, on a few occasions Digikey has sent me a few extra chips (the junk on the bottom of the bins? to make me feel good?). Thanks but I’d rather just have what I paid for (complete full trays) than $20 extra worth of their scrap parts!

Another woe with Digikey packaging is digireels sometimes come in 2-3 or sevearl split tapes which are poorly joined together. They almost always fail in the pick and place, the pullback tape just flies off, or the metal strip joining piece rips apart, its just junk. I basically never order digi reels anymore either – their leader tape is just as useless, a waste of extra $7 digireel fee. I just pray every time that they will send me 1 continuous piece of tape and I deal with the leader tape myself.

On several occasions Digikey sent me tray parts that have bent pins (improper stacking of trays or chips were out of place and stacking trays bends the pins), this of course goes unnoticed until testing, and requires manual rework to salvage the failing boards. This type of thing is only fun while you read about it. Meanwhile Mouser never managed to match this performance:

Mouser’s packaging

Mouser on the other hand has are stellar at extra care with packaging and padding the trays before they package them. And just as great with dry packs and professionally packet parts. I don’t recall ever being upset with them cleaning their component bins and dumping N number of split tape of a certain component, it’s always nice to have 1 continuous piece of tape for use in the pick and place. No complaints, just great service.

Digikey vs. Mouser Shipping

Now part two of Digikey’s mishaps. Getting my order shipped the same day at Digikey has been hit or miss. This last last one (placed April 12, 10am)  shipped the next day (April 13 12pm) using the same ground service. So their same-day shipping falls short and I have to eat any potential delay penalties myself (or just spend a lot more on shipping in hope they might ship the same day). The order was just over $1500 so maybe a little off their priority radar, oh well!

Enter Mouser. At the same time (minutes apart) I placed $500 order, also with ground shipping. Surprisingly (I can’t recall them ever doing this) they also delayed shipping past the promised same-day timeframe. Very unusual. However, I got a nice email saying my shipping was upgraded because of the delay, to Next-day Air. Nice, now I’m getting my parts even faster so the delay actually makes things better.

And as a past experience with Mouser – it seems like if you spend at least $500-1000 they always upgraded me to next day air, sometimes 2nd day air, it’s pretty much routine. I don’t mind that, thanks Mouser, you have been awesome, please don’t change!


Other good distributors I’ve had good experience with:

I’ve had good experience with:

  • Future Electronics
  • Master Electronics
  • onlinecomponents.com
  • Verical (Arrow company) has been OK but only used it a few times

The useless bunch (IMO):

Newark/Element14 seem to be pretty disabled in terms of stocks and shipping to the USA, I think I ordered once or twice, pretty helpless sites and part search engines.

Arrow – I will avoid it in the future. I ordered from them a few times, my last order was a pretty incredible experience buying a large batch of components. I was in a crunch and had no other choice but at Digikey who charged double, so I bit the bullet. The site is pretty helpless, parts ship from various global locations and this last order took “forever” to arrive from Netherlands. A few months later some rep Jack K. starts calling me to pay them some extra due tax they added after I placed the order (never mentioned at checkout or on the original invoice) – yeah this really happened in 2017. I paid just to get them off crawling on my back, now I get Jack’s spam email every week or two trying to “bid” me on more parts. Dear Arrow and Jack – you don’t charge a customer again after the deal – you and your stone age practices are dead to me and you lost my business for eternity.


Some tips for beginners:

  • I use ECIA-authorized to look for components at multiple suppliers and compare pricing.
  • part of the fine art of making a product is designing around parts that are commonly available, avoiding exotic expensive low stock parts that might be here today at a distributor and gone tomorrow
  • when possible choose main parts that have alternatives – both in packaging/pinout and in usage – this gets harder with part complexity – it’s easy with passives and basic components, and harder with larger/more complex components. Having a fallback part that is pin compatible and/or firmware compatible can be crucial
  • use common sense, choose bigger rather than smaller. I don’t mean DIP, but go with 0603 rather than 0402 if you don’t have to use small. Your eyes don’t get better either
  • if you’re not the end consumer of the components (ie. you use them to make stuff you sell), submit a certificate of sales tax exemption to get 0% tax added to your orders

Made in china?

  • do yourself a big favor – don’t buy chips or complex parts mass made intentionally poorly and so very carelessly in china. I agree there are reasonably known good parts from china but in general you get screwed by china if you hinge any product on chinese (non)quality. The exception in my case is the radio modules. But finding a reliable good supplier is pretty much unheard of and inadvertently you will get a mix of good and crappy batches of parts from the same supplier. Chinese companies are very preferential and will screw you without a blink regardless how much business you created for them. I limit my china supply to very simple parts like headers, wiring, nuts and screws, magnets, which can’t go wrong in many ways. I wish I never had to make PCBs in china but unfortunately PCBs are too expensive in the US even in larger volume. WRT to HopeRF radio modules, I’ve been somewhat on the edge all these years. Things start to change and lots of other chinese companies start making SX1231 and LoRa modules which look appealing. I would gladly pay more for US made modules, but nobody can come even close to chinese pricing it seems, so we continue to agree to be at the mercy of these chinese folks.

So dear reader – has this article been helpful to you?
Have you had similar experiences with these or other suppliers?
Leave a comment, even hate mail is OK if I can learn from it, suggest improvements, share your own woes or awesome tips, anything constructive is welcome!

Back to work! Ready to stuff some boards?

9 thoughts on “Component sourcing and Mouser vs. Digikey Pros and Cons

  1. Felix, well said!

    Thanks for reminding me why I don’t try and market a product like Moteino. I get stuck with the “same day” shipping that turns into a day or two later all the time. It just seems part of the culture now.

  2. Great post! I use the same suppliers for my products, and also struggle with many of the same issues. It’s nice to know I’m not the only one.

    I would say this post is a good reason why you should take another look at a professional PCB assembly service, instead of doing it yourself. You’ll pay more, but look at all the hassle and aggravation you’ll save. If you consider the dollar value of your time, IMHO it’s absolutely worth it. Let the assembly service deal with broken reels and partially-filled trays and shipping snafus and everything else. And the assembly service is a bigger customer than you for D&M, and will have more leverage getting the best D&M prices and terms, or convincing them to break up a tray or sell a part below the minimum quantity. For a small amount more, the assembly service can also test the finished hardware and put it in your retail packaging. Unless your life’s goal is to be a supply logistics manager or pick-and-place operator, why not leave that work to someone else, and spend your time where it will have the biggest payoff: making new designs?

    Any idea what’s behind this passive component shortage? I hadn’t noticed it. Searching Digikey for 0.1 uF capacitors, the shortage seems to be worst for your 0603 component size. 0805 size is cheaper, and 0402 is much cheaper.

    ECIA Authorized looks like a great site for comparison shopping of electronic components. I had been using Octopart, but this looks like a better option. Thanks for the tip!

    I can’t agree with your view on Chinese-made parts. Virtually all these components are made in China or elsewhere in Asia (Malaysia, Thailand, etc), so if you’re not buying components made there, I don’t know where they’re coming from. But I would agree that finding a reputable supplier is critical. I’ve had good experiences buying parts from Chinese vendors like Seeed and Elecrow. If you’re buying from some no-name vendor on eBay or Aliexpress (and I am guilty of this myself), then sure the quality and consistency of the components may be poor, regardless of what country they’re coming from. But if you can tolerate some problems or a high defect rate, it may still be worth it if the price is right.

    I’m guessing that you have a lot of one-off prototype component orders? Shipping time is mostly irrelevant to me, as I would think it would be to you when ordering 1000 or 10000 components at a time. Presumably an order that size would be made well in advance of when your existing stock runs out. I always choose the slowest/cheapest shipping option.

    Digikey’s parametric search is indeed great, and they’re my preferred component supplier. I generally find Mouser’s prices to be more expensive, and have only ordered from them once or twice. While Digikey is my favorite, I also use Newark and Arrow frequently. Yes their web site search functions are weak, but they can have good pricing on a specific component that’s identified through Octopart. Newark in particular often has promotional pricing on certain parts that’s substantially cheaper than the competition. I’ve never had any difficulty with Newark or Arrow orders, and always received my parts within a few days. I agree your mishandled Arrow order with delays and taxes sounds horrible, but fortunately that’s not been my experience.

    • Steve,
      Thanks a lot for the in-depth analysis and response. I am manufacturing many different products. About 4 years ago I invested in my assembly equipment, a very large investment at that time. But it has paid off, and after all this time I am an expert in using the machines efficiently and quickly, while dealing with their quirks. Yes it requires my time but it’s still not daily and only a few hours at a time to make up to many different panels of products to replenish stocks. So i don’t see it as a drainage of time and resources. I think I am saving well worth above what a PCBA service would charge. I can also do it very quickly if a client wants a custom batch of something. And I can do it at 2AM if I want to, I don’t depend on any 3rd party. I value that very much. I can also sell some of the actual components used which is a plus. If I had to ship parts to a PCBA or arrange the BOMs for their format I think I would still spend a fair bit of time (and then every time it needs to change). You obviously know more about this and it may work well for the few products you are focused on. For me having my own shop is highly desirable at this stage.

      Regarding components and china:

      – I have relatively few prototype orders, my main orders are the production quantities I use in my existing products, and often the prototype parts get bundled with them
      – I buy large quantities from 100-1000 for expensive items, and from 1-4 reels of the passive/small/cheaper components
      – I bundle and buy lots of different parts in every order, I never really place an order for a single reel of something unless its an emergency. So I try to consolidate orders and also save on shipping. If a single item (in quantity) costs significantly less elsewhere that it justifies paying separate shiping and still save significantly (not just $10 or 20) then I will do it, otherwise I prefer to bundle even if it costs slightly more
      – theres a distinction between MADE and ASSEMBLED in china
      – almost everything is assembled in china these days – ex: even high end equipment from keithley
      – I dont think a lot of brand name components are made in china – usually elsewhere in asia as you say. Brand names like panasonic, murata, yageo, vishay, all manufacture components in asia, but to my knowledge not in china.
      – yes there are some good chinese suppliers, my time is very limited in testing chinese suppliers, but finding the good deal from the good consistent supplier has been challenging

      Maybe this discussion should continue in the forum where we have better posting and reading tools than this comment section 😉

  3. Great write up Felix! I also order mostly from Mouser, unless I can’t find parts there. Also Chinese suppliers can be dodgy, but I found with some persistence it’s possible to find good ones (from Alibaba). Difference in pricing from those suppliers vs Mouser/Digikey is mind blowing (for example Si temp/humidity ICs or DS3231 RTC chip are about 50% less). They ship within a week too if you pay extra for DHL… Sure it takes time, multiple small “sample” orders and a lot of back and forth communications until you find your “guy”.
    But yes, Mouser is exceptionally great, I usually get parts form then within 4 days even if I choose regular USPS method (I live in NY). And they package everything very neatly, even if you order just one or two ICs (sometimes a little excessive with desiccant and moisture indicators 🙂 )

    • Hey Len, great to hear from you 🙂
      You and Steve might be buying less parts than I, from what I can understand from your posts. So buying from china is OK, if you find the good supplier. Timing is pretty critical and even if a Digikey order from just 2 states away takes 5 days to arrive with ground shipping, cheap shipping from china can take a month. So using DHL to buy 1 type of component, can sometimes not be worth it. If you buy a full reel of something, provided you established a good supply, then it makes it worth even if DHL costs $20-30 more. My china critique tends to be more towards small quantity small supplier ebay/aliexpress/alibaba open market. Those that have thousands of sales usually dont really care much of anything (quality, service, packaging) and I often get less than the ordered quantity, or I get most but not ordered products if ordering more than 1 type of component from the same seller, or the packaging is poor and things get damaged. Not to even go into fakes and clones and stuff like that. China is great at faking and cloning so Mr. Trump – how about imposing a ban on clones and fakes? Don’t those hurt the US economy?

  4. Unfortunately I had a terrible experience with Mouser. I’m in Argentina, so for some reason, Mouser redirects me to Mouser Mexico (which is nothing more than a call center there). I placed my order at 11AM and the next day at 4PM they send me an email asking me for a ID. Because “there is an issue with my payment”.
    So I send them my ID. Next day, still no news of them. So again I contact them. They tell me there is still “an issue with my payment”. So I ask them to cancel the order and return my money, that they don’t seem like a serious business if they pull this kind of thing. So they just cancel my order and that’s it. Not even a “sorry”.
    So I go out of my way into their website to find out how to let the USA office know about this (because the site keeps trying to redirect me to Mexico). They tell me it’s probably because the shipping address didn’t match the billing address. I tell them: that’s not the point. The point is you took 2 days to tell me nothing and in the end I had to call them to see what’s going on. The USA chat was a little more helpful and promised me “they would escalate this to a manager”. 3 hours later no news from the manager though.
    Oh, and no news about my money. They charged my debit card but they haven’t canceled the carge. They’re holding my $115. It looks like I’m going to have to sort this out with my bank.
    I regret even trying them. Digikey has served me well for years. The final price difference was only $10… that $10 has costed me so much trouble they are just not worth it.

  5. Great article! Just a couple of comments regarding Mouser’s shipping policy & costs:
    1. It costs a minimum of $8, no matter who your choice of shipper is.
    2. If you choose USPS, your order will not ship the same day, regardless of the time your order is placed.

    • Things have changed since I wrote this blog. Digikey overall has better (fixed) shipping pricing and free upgrades from Ground to 2nd Day for same price (vs Mouser’s prorated based on order value). I find myself using Digikey more these days, other than the occasional component miscount (cut tape parts) I haven’t had major issues with them.

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