This article is part of TechXchange: Shortages of chips and counterfeits
What you will learn:
- Take a micro-carrier-card approach.
- Double footprint design and substitution of secondary components.
- What is a last purchase?
We’re well into 2022, and at this point supply chain issues are still a challenge for those of us creating and maintaining existing products. In some ways, the current situation is no different from the pre-pandemic era when shortages of one component or another were a reality.
What remains unusual is the continuous and simultaneous shortage of several major and minor components in several categories. This adds new wrinkles to the work of engineers in creating new products and maintaining products already in the market.
A number of large companies have been able to handle the supply shortage better than small or medium-sized companies, but even some of them and their huge supply organizations are struggling. Still, there are those like Tesla, according to a recent NY Times article, who are successfully meeting the challenges (although many details are being kept under wraps at Tesla). A Reuters article explains how Apple is dealing with supply chain issues, in part through smart purchasing.
Not to be overlooked, the way products are designed can have a big impact on mitigating supply chain challenges. While supply and demand alignment issues may improve in a matter of months or years, engineers still need to get the product out now.
Here are some design best practices to help minimize supply chain issues:
1. Auxiliary microcarrier board
As designers, we hate adding extra cards to a system. This has a negative impact on costs, but it may now be necessary. This requires careful consideration of the carrier circuitry to accommodate more than one micro version or other parts of the product.
Such an approach results in flexibility and the ability to pivot as needed in response to inconsistent supply availability. Along with this method is an impact on the firmware which may now need to be ‘smart’ enough or have functionality to accept alternative hardware.
The carrier card approach gets around issues where one can get the same part in multiple package variations. Using an existing circuit board with a microcarrier board can provide an advantage as the main board may already have undergone EMC testing or other regulatory certification processes.
2. Dual Footprint Design on Single PCB Systems
In some cases, it may be possible to find components in multiple package configurations. PCBs can be designed to fit multiple footprints. This especially applies to alternate package variants of the same mic from a single vendor source. As with the carrier board concept, firmware intelligence or adaptability may be required. Designing for flexibility is key.
3. Design for Secondary Component Substitution
For secondary components, such as memory chips, look for similar parts with adaptability in firmware to allow substitution of parts based on available supply. Often it is important to pay close attention to drivers which can detect subtle differences between components. For example, one can design for the same function with slightly different pinout signals or pinout locations in the board model.
4. Accelerate to the next generation
Not all products work with the latest and greatest chips. If you’re working with an older design, there could be end-of-life issues. Of course, we can almost always make one last purchase, but it’s a palliative.
Supplies can be so short that there can be considerable delays in obtaining materials for a final purchase. I use the words “almost always” here because the notice given for last purchases can be very short these days. In fact, there are times in the current environment where suppliers suddenly discontinue parts with no chance of a final purchase.
If it’s raining lemons, make lemonade. Now may be the time to proactively move to the next-gen chipset so that the product fits the parts that chipmakers want to produce in volume. End-of-life components are often only available in low volumes to the product manufacturer. This can lead to increased costs or the chipmaker’s reluctance to invest factory resources in producing a part if shutdown is imminent.
5. Strip the parts from the evaluation boards
Removing coins from rating cards is a desperate move that can be used in extreme cases. When parts are needed for development or early low-volume production, there can sometimes be an rush to purchase evaluation boards, harvest parts from those boards, and use them for immediate need. In a crisis, necessity is the mother of invention.
6. Last minute and risky purchases
Last, but not least, there is the age-old practice of buy-last-time and risk. These are not normal times. The current situation has led to companies stockpiling parts to a degree never seen before, and this is disrupting the normal market forces of supply and demand.
Take a careful look at the supply; it may be advisable to obtain them well in advance. The risk, of course, is that the wrong parts or quantities were pre-ordered. Applying “technical judgement” to the decision-making process can be helpful in having the parts provided when needed.
Today, it is not uncommon to see lead times of 50 to 100 weeks for parts. Worse still, you can’t always trust the given deadlines. Delivery times are regularly extended by 30 to 40 weeks beyond those indicated at the time of the order. What was once a minor checkbox to investigate parts availability and second supply has become a critical issue. Using some of the techniques described earlier can help you get through this supply chain crisis.
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