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Flexible Thinking: Integrated Passive Devices—Design Solutions With Many Benefits

Many good ideas have often escaped broader appreciation in the electronics industry. Some have come in and out of favor over time, including the integrated passive device (IPD).

The first IPDs appeared in the late 1980s and early ’90s, driven by a desire to miniaturize electronics while decreasing cost and increasing performance. Those drivers remain key today. Just like an IC package, engineers integrate resistors, capacitors, inductors, etc., into a packaged device, and then mount and interconnect them to a printed circuit board. This can significantly reduce the number of discrete components that might otherwise be required for an assembly design, and using an IPD can simplify PCB assembly processes and lower assembly and final product costs.

This IC-like manufacturing process would involve depositing thin layers of resistive, dielectric, and conductive materials onto a suitable substrate (often silicon, glass, or ceramic) using physical vapor deposition (PVD) or chemical vapor deposition (CVD). However, it is also possible to assemble an IPD discrete device using a traditional SMT process and solder to mount the resistors, capacitors, and inductors to a small PCB or ceramic circuit that has terminations at designated locations (Figure 1).

Other benefits of IPDs include:

• Miniaturization: To shrink the size of products, designers have occasionally used IPDs to save space on printed circuit boards to replace myriad discrete passive devices.
• Performance improvement: Integration of passives into packages can reduce the parasitic effects that often occur in some designs and can lead to better electrical assembly performance.
• Enhanced reliability: The integrated passive component can be manufactured and assembled using fewer solder joints and interconnections, resulting in more reliable electronic designs. (This is something that has not gone unnoticed by me and is now considered an opportunity for exploration using the Occam Process for their manufacture.)

With the benefits just accounted for, it should not be too surprising that integrated passive devices have found some reasonably broad acceptance. For example, when one attempts to establish where IPDs have found greatest acceptance, it’s almost everywhere. Today, IPDs are widely used in various applications, including RF modules, wireless communication devices, medical devices, automotive electronics, and consumer electronics. One highlightable benefit of IPDs is their ability to enhance performance while saving space, making them suitable for high-frequency and high-performance application. However, in broad brushstrokes, the following are a few more specific places where they have provided benefits.

In consumer electronics, such as smartphones, tablets, and wearables, the adoption of IPDs has reportedly been quite high due to the stringent space and performance requirements as discussed earlier. One estimate has it that perhaps 70% of modern consumer electronic designs in recent years have incorporated some form of IPD.

As new cars continue to consume evermore electronics, the automotive industry has demonstrated significant interest in the adoption of IPDs, particularly in advanced driver-assistance systems, infotainment systems, and power management modules to name just a few. Estimates of adoption rates in automotive are similar to that of consumer electronics. In telecommunications equipment, especially for RF and high-frequency applications (think 5G), IPDs are widely used to enhance performance and reliability. With a solid foothold, it is likely they will continue their march into coming generations of products. The same holds true for medical and industrial products, and the list goes on.

When it comes to suppliers, a long list includes familiar names such as Vishay, AVX, Murata, Texas Instruments, Johanson Technology, OnChip Devices, and STMicroelectronics. They offer a wide range of passive electronic components, including resistors, capacitors, inductors, and integrated passive components, with off-the-shelf and custom solutions to meet specific design needs.

Integrated passive devices offer designers an opportunity to significantly reduce their designs' complexity while improving performance and reliability. I encourage you to learn more about them.

Joe Fjelstad is founder and CEO of Verdant Electronics and an international authority and innovator in the field of electronic interconnection and packaging technologies with more than 185 patents issued or pending. To read past columns or contact Fjelstad, click here. Download your free copy of Fjelstad’s book Flexible Circuit Technology, 4th Edition, and watch his in-depth workshop series “Flexible Circuit Technology.”

This column originally appeared in the August 2024 issue of Design007 Magazine.