atchdogs have long been a standard, if slightly esoteric, element of system design, often receiving only secondary consideration after the primary application has been planned out. At their core, they serve a straightforward purpose: providing a graceful means of recovery in the event of abnormal system behavior. At their origin, watchdog timer architectures were simple, implemented via a dedicated application-specific integrated circuit (ASIC), positioned adjacent to the system’s processor (see Figure 1).

In that early form, interaction with the watchdog was typically limited to a simple general-purpose input/output (GPIO) pin. However, as systems have grown in complexity and adopted stricter safety requirements, watchdog implementations have also evolved. In more modern setups (see Figure 2), a watchdog may be integrated into the microcontroller itself, reside in a voltage monitor or supervisory device, or be part of a power management integrated circuit (PMIC), often refreshable through GPIO, I²C, or SPI.

hen a recall is implemented, it hopefully solves the safety issue. But that doesn’t always happen. First, you rarely are 100% successful in retrieving the product or repairing it. And, of course, the occurrence of an accident involving a recalled product can be very difficult to defend. Even worse, an accident involving a product that was unsuccessfully repaired by the manufacturer can be even harder to defend.

The number of lawsuits involving recalled products and products that haven’t been recalled has been proliferating recently. And the verdicts and settlements have been significant.

This article will describe the difficulty of defending the adequacy of a recall, the types of remedies that are offered, and a recent trend of class action lawsuits being filed alleging that the remedy instituted by the manufacturer is inadequate and resulted in economic loss to the consumer or owner of the product.

In addition, if a repair is performed and an accident still occurs, that can also cause a jury to get mad and believe that the manufacturer was grossly negligent. In August 2024, a jury rendered a huge award against Harley-Davidson for allegedly failing to adequately repair faulty software on one of its recalled motorcycles. Unfortunately, there was an accident on the repaired motorcycle that resulted in catastrophic injuries and one death. The jury awarded $240 million in punitive damages and $47 million for pain and suffering, medical expenses, and loss of consortium.

Of course, Harley believes that the accident had nothing to do with the original repair and they plan to appeal. The message here is that if you repair or replace the product instead of refunding the purchase price, you had better be confident that the fix or replacement is adequate and that you have good evidence that it is safe.

IEC 62368-1 addresses numerous hazards, including electric shock, mechanical, heat, radiation, chemical, and fire risks. Yet, its current iteration primarily presumes that safety mechanisms are built-in or are physical hardware safeguards, with minimal explicit focus on control-based safety, especially where hazard prevention significantly depends on or is facilitated by software. In the digitalization and Internet of Things (IoT) era, where software increasingly governs devices—including vital safety functions like overtemperature protection, fire prevention, and other types of hazard monitoring and control—this oversight in considering software’s role in safety assurance demands thorough examination [3‑4].

his is the second of two articles devoted to the topic of inductor impedance evaluation from the S parameter measurements using a network analyzer. The previous article [1] described the impedance measurements and calculations from the S₁₁ parameters using the one-port shunt, two-port shunt, and two-port series methods. This article is devoted to the impedance measurements and calculations from the S₂₁ parameters using the two-port shunt and two‑port series methods.

The overall conclusion of the previous article was that the inductor impedance evaluation from the S₁₁ parameter measurements is not accurate. This article concludes that the two-port series method is the most accurate method for the inductor impedance evaluation from S₂₁ parameters when using a network analyzer.

new version of Technical Report TR18.0-01-25 (TR18) on ESD Electronic Design Automation (EDA) Checks by the ESD Association’s Working Group 18 is about to be released. This article provides an overview of TR18, which offers guidelines for the EDA industry and the ESD design community to establish a comprehensive ESD verification flow. This flow addresses ESD design challenges in modern ICs, including common terminology and required check types. The main requirements are broad check coverage, manual checking limitations, transparency, and integration into the design flow for clear and actionable violation reporting. The document covers generic checks, EDA toolsets, and databases, allowing IC design companies, IDMs, or foundries to implement specific rules in their design and verification flows for automated checking.

• Product Verification Sign-off Phase
• Product Validation Phase

ecently, I worked on a radiated emissions case involving narrowband emission failures in the 100 MHz to 1 GHz range. Identifying the source of such narrowband noise is usually straightforward, and, in this case, a near-field sniffing probe quickly led us to the culprit: the clock signal of a high-speed SPI line between the microcontroller and the flash drive on the PCB. This is demonstrated in Figure 1.

However, during troubleshooting, I discovered something unexpected—other I/O lines, much slower by nature (such as an I²C line running at just tens of kHz), were also exhibiting the same 100 MHz harmonics. This became evident when I used an RF current probe to measure common-mode noise on the wires connected to the PCB, shown in Figure 2.

To mitigate the noise on the other I/O lines, I initially used high-impedance ferrite beads. When selecting ferrite beads, a simple rule applies:

• Their impedance should be high at the noise frequency to effectively suppress unwanted emissions.

or those that follow our “On Your Mark” columns, you know the emphasis placed on the value of ANSI Z535 – the U.S. standards that create a guide for the design, application, and use of signs, colors, and symbols intended to identify and warn against hazards and for other accident prevention purposes. These standards, along with their international counterpart, ISO 3864-2, are effective starting points in helping you to develop adequate warnings. Recently, we had an exciting new development in this family of standards: the release of an all-new seventh standard. In this article, we’ll explore the new standard and how its principles can be used to create effective warnings that drive safety.