Signal Integrity, Power Integrity, & EMC Blog 

There was a time when power integrity (PI) was treated as an afterthought—a minor checklist item at the end of a hardware design cycle. You tossed a few extra decoupling capacitors near the FPGA or processor, crossed your fingers, and hoped the board wouldn't glitch. Those days are officially over. With today's high-performance silicon drawing massive currents at sub-1V levels, power delivery networks (PDNs) have become some of the most complex, high-risk components of modern

With contributing authors Heidi Barnes (Keysight), Steve Sandler (Picotest), and Kathleen Love (Signal Edge Solutions Importing a SEPIA measurement into Keysight ADS gives you all of the information you need for your design to achieve stability in less than a minute, even if it’s a non-LTI system. In this blog, we will discuss how to leverage these tools to get actionable insights on a design’s stability. In a world where VRM control loops are no longer consistently linear, t

Figure 1: DDR5 Interposer by EyeKnowHow Why Use DRAM Interposers for Signal Measurement? JEDEC standards define the DRAM input parameters at the ball of the DRAM, since it is the last point a probe can access for signal measurement. In practice, with designs becoming increasingly complex and compact, accessing the ball of the DRAM can be a challenge. Or sometimes, the closest measuring point is centimeters away, which will result in an inaccurate reading of the signal at the

In this video, we are performing a non-invasive stability measurement (NISM) on our PDN to check impedance. This specific stability measurement allows us to evaluate the health of the power delivery network without accessing with the feedback loop. When looking at the measurement graph in the Bode Analyzer Suite, we can see that there is a sharp peak in the graph, indicating PDN instability. We are measuring the output of the voltage regulator module (VRM) and using the Bode

Learn about how crosstalk in power distribution networks (PDNs) is a significant issue amplified by ground loops.

In power integrity analysis, we primarily concern ourselves with the impedance response when evaluating the frequency domain. Specifically, we focus on the magnitude of the impedance response and tend to neglect the phase of the impedance response. After all, the phase can be extracted from the magnitude: Flat impedance magnitude across frequency is purely resistive with 0° phase -20 dB/decade slope is purely capacitive with a -90° phase +20 dB/decade slope is purely indu

While prototyping a design, it is incredibly helpful to have an in-house EMC pre-compliance testing setup to troubleshoot your product. Having this capacity can save you from having to send your design into a third-party lab for multiple rounds of compliance tests, speeding your design cycle and saving costs in the long run. Investing in your own EMC test setup may seem like a daunting prospect, but you don’t need to spend tens or hundreds of thousands of dollars on an anecho

Calibration and measurement accuracy are critical in power integrity and impedance analysis, but they’re often hindered by time-consuming setups, inconsistent connections, and external interference. Picotest’s new Calibration Test Fixture (CTF) addresses these challenges head-on, offering a faster, easier, and most importantly, repeatable measurement process. By eliminating the need for SMA connectors on mount boards and integrating internal ground loop isolation, the CTF str

Achieve First-Pass Success in AI and Chiplet Designs with Measurement-Validated SIPI Modeling The future of high-performance computing—AI accelerators, custom ASIC design, and complex Multi-Chip Modules (MCMs)—is defined by advanced packaging. However, as process nodes shrink and data rates soar past 112 Gbps, and even 224 Gbps, the package substrate has become the single greatest risk to performance and time-to-market. At Signal Edge Solutions, we don't just simulate; we gua

Diagram of sample Signal Edge Solutions mobile lab setup In an increasingly RF connected world, EMC compliance testing is necessary to ensure products are robust enough to operate in a safe and reliable manner in consumer and commercial environments. Nearly every country has EMC regulations and standards that electronic devices or machines on the market must be compliant with for their intended use. Products that fail to meet electromagnetic compatibility (EMC) compliance can

Touchstone Models and Scattering Parameters: Fundamentals and Importance in SI/PI Touchstone® (SnP) models are a key asset in the fields of signal integrity (SI) and power integrity (PI) when analyzing high-data rate, high-speed designs. These frequency-domain models characterize the linear behavior of passive interconnects and components such as PCB traces, vias, connectors, and packages by describing how signals are reflected and transmitted at various ports across a wide r

Solve complex power integrity challenges with the R&S MXO5. Our guide shows you how to measure PDN impedance, use advanced probing, and automate testing.

What are the Challenges with Manual Transient Step Load Response Testing Measuring power rail transient performance in response to high current dynamic loading is essential for power integrity validation. The behavior of power rails during transients is critical for system stability, and both steady state and transient responses must be analyzed. This is because modern digital components, like FPGAs, CPUs, and GPUs, demand fast, stable power, and any voltage fluctuation—or "t

There’s a unique mix of excitement and anxiety that comes with powering up a new hardware design for the first time. After weeks or months of meticulous schematic reviews, countless layout changes, and thorough simulations, the hope is always the same: maybe it’ll just work on the first try. But more often than not, that hope gives way to the harsh reality—something’s not working correctly. Whether it's an unstable output, unexpected thermal behavior, or a total lack of power

The grind of repetitive lab tasks can be a major drain on an engineer's time and energy. Think about those hours spent manually collecting data for something like a Voltage Regulator Module's Vout vs. Iout characteristics, the process is tedious and prone to human error. Fortunately, the solution is closer than you may think. Today's test equipment is increasingly capable of automation, offering a powerful path to efficiency and accuracy. If you've been wondering how to get s

In Part 1 of this blog series, we discussed why we measure impedance, how to measure impedance of a VRM, identifying instability using these measurements, and how to fix this instability. In part 2, we will review the changes made to the EVM, as well as the effects of these changes in both the frequency domain and the time domain. As a quick refresher, we previously measured the impedance on Wurth Elektronik's 178013801 EVM with a 1Ω DC load and an output voltage of 0.85V. We

Time and time again, we discuss that flat PDN impedance is important to achieving low noise power delivery solutions to a load. However,...

Transient voltage responses of a PDN subjected to periodic step loads. Large signal measurements are essential to Power Distribution Network (PDN) validation. By stressing the PDN, they reveal transient phenomena that are otherwise difficult to surface. This article discusses capturing large signal phenomena with the Picotest P2105A (S10) Transient Load Stepper browser probe. We recently explored Large Signal Phenomena using the MXO5 - Sequential Trigger Measurement Setup. PD

The constant development of new and emerging technologies, such as Artificial Intelligence (AI), electric vehicles, and 5G/6G communication systems, are driving higher board densities than ever before. This has led to the popularity of Voltage Regulator Modules (VRMs) as a way to help alleviate space in the PCB design. Depending on the power requirements of an application, power supplies can consume a significant amount of real estate on a PCB design to achieve a stable and l

If you're looking to select a power supply to use in your design, read this before dropping it or a VRM into your schematic.