Check with your EMS each time before sending your BoM.

Most of the electronics design world is by now aware we’re in a very serious period of component shortages. Ceramic capacitors seem to be the hardest hit, but other passives, as well as a variety of connectors and silicon parts, are also caught up in the shortage storm. Allocation and shortages hit every few years, but this one seems the worst in recent memory. It could be a problem until 2020, and the supply chain and world of components manufacturers will likely be a different animal coming out of it.

So, you might ask, isn’t that just a problem for high-volume producers? No, I would answer. It affects anyone, regardless of volume. The exact way it hits and what you can do about it may vary, but it has, or soon will, hit all of us.

Here are five things you can do to minimize the effects. I’m going to start with the most important thing for those who need low volumes.

1. Check the availability of all your parts immediately before sending us the bill of materials. Do this as the very last thing before sending your BoM to your assembly partner! It’s not uncommon for a part to be in stock one day and out the next. We’ve even seen cases where the part is in stock in the morning and out by the afternoon. If your EMS is quoting and ordering your parts, verify they are in stock as the last thing you do before sending your files.

Almost every BoM we see these days has one or more parts that are out of stock. At Screaming Circuits, we send an email about the parts being out of stock. We can’t do anything else until we hear back from the customer. An EMS can’t build without parts, and won’t know your design like you do, so it can’t guess at substitutions. A last-minute check can save days of delay.

2. Put one or two alternate part numbers in your BoM, especially for passives. As I said above, the EMS probably won’t know your project, so it can’t pick a substitute for you. Give some alternates. Ask your EMS contact where to put alternates. Different EMS companies like to see the information in different places, so ask first. And be sure to indicate in the special instructions that you’ve put alternates in the BoM.

3. Consider your parts’ values carefully. You may be able to pick something with better availability. The 0.01µF capacitor is the hardest-hit component right now. It’s the most common bypass capacitor. Some designs need exactly that value, but many don’t. It may be easier to find an 0.022µF, a 0.0047µF, or something else close. If that’s the case, choose a close-enough value that has better supply, or put a close-enough part in as an alternate. Just don’t forget to verify it in your design first.

4. You might need a slight redesign to use a smaller package. Since smaller packages can be used in more applications, many suppliers will allocate more of their foundry capacity to smaller form factors like 0402 and 0201 sizes. Some component manufacturers have said they will permanently discontinue anything bigger than 0402 parts, except when absolutely necessary.

Stick with 0402-size passives. It may be easier to find the parts you need in that package, and those size parts will be the first ones to come back in stock.

5. If the EMS sends a message about a part it can’t find, respond as quickly as possible. EMS companies do their best to avoid any delays in this process but can only do so much. Help them out by getting back to them as soon as possible, and don’t be afraid to give them more than one part number to try.

Shortages and allocation can be an annoying problem and can cause delays and other issues. The good news is the problem is the result of the booming design world and advancing technology. It will get better, and following these five tips can help prevent delays. Don’t forget to check your parts for availability right before sending in your BoM. I mean it!

Figure 1. MLCCs are among the frequently out-of-stock parts.

Duane Benson is marketing manager and chief technology champion at Screaming Circuits (screamingcircuits.com); This email address is being protected from spambots. You need JavaScript enabled to view it..