Electronics broadly are moving toward higher bandwidth, lower latency, and denser system integration. High-speed interconnects such as PCIe Gen 5/6, multi-lane Ethernet, and AI accelerators now sit at the center of servers and compute platforms. Alongside these advances, power delivery networks have become more sophisticated, with Integrated Voltage Regulators (IVRs) switching anywhere from 2 MHz to 100 MHz to optimize efficiency and transient response.While these changes deliver performance benefits, they also amplify electromagnetic interference (EMI) challenges. As dies, power stages, and interconnects are packed into increasingly compact footprints, the EMI margin available to designers shrinks. Power integrity and signal integrity are closely coupled, and even small increases in ripple or noise can degrade system-level compliance.The switch from discrete passives to co-packaged and embedded components means that inductors and ferrite beads are integral to the overall architecture. Namely, their selection directly impacts regulatory compliance, overall efficiency, and thermal headroom. As such, engineers now face the task of choosing components that meet performance specifications and maintain EMI control without compromising form factor or power density.<h2>EMI Sources and Their Impact on System Design</h2>EMI in modern electronics stems from multiple sources, but power delivery noise and signal path coupling are arguably the two most prominent.Power delivery noise arises in DC/DC converters and IVRs, where high dI/dt transitions drive ripple into sensitive power rails. As switching frequencies climb toward tens of megahertz, the harmonic spectrum broadens and pushes more noise into bands where it can couple into critical signals.Signal path noise coupling is especially prominent in server motherboards. Devices like PCIe re-timers, Ethernet controllers, and switch ASICs operate close to emission compliance limits and rely on stable supply rails to maintain signal integrity. Without effective suppression, conducted EMI from the power delivery network can migrate into these ICs, degrade link stability, and increase error rates.Generally speaking, EMI can manifest as either conducted interference, traveling through rails and interconnects, or radiated emissions, emanating from traces, packages, and cables. Both impact compliance and system function. For example, in GPU and AI accelerator subsystems, inadequate EMI control at the power entry point can result in corrupted data transfer and reduced throughput.Complicating matters further, regulatory compliance pressures continue to increase. Engineers must deliver systems that pass tight EMI testing without sacrificing board density or introducing excessive power losses. This demands a component-level strategy where inductors and beads are selected based on both electrical and mechanical performance.<h2>Ultra-Thin Inductors for High-Frequency IVRs</h2>As switching frequencies in IVRs approach 100 MHz, inductance requirements shift downward, and package constraints dictate smaller case sizes. Traditional wire-wound inductors cannot always scale to these requirements, leading to the adoption of thin-film inductors optimized for high-FSW applications.Mounting strategies are therefore instrumental to minimizing EMI. Ultra-thin inductors can be placed die-side, land-side, or embedded within the interposer, and these placements enhance current level transient speed by reducing loop area and parasitics. Murata’s ultra-thin solutions are available in footprints as small as 0402 (1.0 x 0.5 mm) and 0603 (1.6 x 0.8 mm), with single devices and array options for multi-phase regulator designs.Beyond size reduction, these inductors offer the benefit of a low-profile form factor that enables mechanical integration without increasing z-height in stacked-die or co-packaged environments. Placement flexibility also helps balance thermal hotspots, thereby improving overall reliability.Customization is another strong suit. Murata’s UTL series enables the tuning of inductance, DCR, and footprint to match the specific requirements of each package VR, ensuring that inductors integrate cohesively with both the electrical demands of the IVR and the mechanical limitations of the package. Ultimately, by reducing EMI at the source,  these inductors improve regulator efficiency, maintain compliance margins, and support the continued scaling of high-frequency IVRs.  <h2>Ferrite Beads as Power Rail Filters in High-Current Circuits</h2>Where inductors address EMI at the switching node, ferrite beads are essential in filtering noise on the power rails themselves. Their function is to present high impedance at noise frequencies while maintaining low DC resistance (DCR) to minimize voltage drop in high-current paths.The parameters of Murata’s ferrite bead families illustrate this balance.<ul><li>The BLM18SP series (0603) achieves current ratings of up to 3.7 A at 85 °C, with a DCR as low as 0.022 Ω, while offering impedance values of up to 1000 Ω at 100 MHz.</li><li>The BLM21SP series (0805) supports up to 2.8 A at 85 °C with a maximum DCR of 0.04 Ω</li><li>For extreme high-current environments, the BLM31SN and BLE32 series extend this performance.</li><li>The BLE32SN120 ferrite bead supports 20 A at 85 °C with a DCR of 0.0006 Ω, providing EMI suppression without significant IR drop.</li></ul>These specifications directly translate into system-level benefits. On server motherboards, PCIe re-timer ICs often require rail filtering to prevent supply noise from coupling into signal paths. Similarly, beads can isolate noise between CPU, NIC, and GPU rails without affecting transient response.Performance stability under load is also vital. The BLE32SN120 maintains an impedance of over 25 Ω even at a DC bias of 5 A to guarantee consistent attenuation across varying load conditions. For engineers, this stability reduces the risk of noise leakage under real-world operating currents.The trade-offs lie in bead size and impedance selection. Higher impedance improves noise attenuation but can increase insertion loss, while lower DCR reduces voltage drop at the expense of filtering effectiveness. Murata’s broad portfolio provides flexibility to balance these trade-offs according to system needs.<h2>Matching Component Architecture to EMI Profiles</h2>EMI suppression is not achieved by a single component but through a matched architecture of inductors and beads. Each has a distinct purpose in addressing different points of noise generation and coupling.For high-Fsw IVRs, ultra-thin inductors mounted close to the load reduce switching loop parasitics and enhance current level transient speed. Meanwhile, ferrite beads placed between the regulator output and load isolate sensitive devices from conducted noise on shared rails.Co-design considerations are equally important. Embedded inductors free surface board space, allowing beads to be placed closer to load pins where they are most effective. Low-DCR beads, such as those in the BLE32 series, prevent excessive IR drop in multi-rail, high-current environments typical of data center and networking hardware.A practical example is a server NIC. Here, a land-side UTL inductor can serve the VRM, while a BLM31SN bead filters the supply rail feeding the NIC. This pairing offers a path toward EMI compliance without requiring oversized passives that consume board space and minimize efficiency.<h2>Designing for Future EMI Requirements</h2>The next generation of electronics will push EMI challenges even further. Switching currents are rising, frequencies are accelerating, and packaging density continues to increase. These shifts heighten the risk of EMI coupling across rails, traces, and interconnects.Mitigation strategies must therefore start early. Selecting thin-film inductors and high-current beads during initial design phases reduces the likelihood of compliance failures that can trigger costly redesigns. Customization is central to this approach. By tailoring parameters such as inductance, impedance, and DCR, engineers can align component behavior with changing rail specifications and transient response needs.Collaboration between system designers and component suppliers will also be necessary. Predictive EMI mitigation, where solutions are co-optimized in advance of full integration, means that compliance can be achieved without compromising performance or density. Such a proactive approach is tangential to industry trends toward co-packaging and heterogeneous integration, where component choices directly shape system outcomes.<h2>Conclusion</h2>With system performance hinging on both compliance and efficiency, engineers require components that address noise at multiple levels.By providing engineers with a broad portfolio of customizable inductors and beads, Murata unlocks designs that meet today’s standards and anticipate tomorrow’s challenges. For systems ranging from servers to AI accelerators, these components make balancing EMI, efficiency, and mechanical integration a reality.<a href="https://pim.murata.com/en-us/pim/details/?productCategoryId=ferriteBeadInductortypefilter&amp;partNum=BLE32SN120SN1%23" target="_blank">Read more at Murata</a>.

Explore how ultra-thin inductors and high-current ferrite beads deliver superior EMI mitigation, power efficiency, and reliability in high-density, high-frequency electronic designs.

EMI Mitigation in High-Density Designs with Ultra-Thin Inductors and High-Current Ferrite Beads

A technical deep dive into the NMOS symbol, working, and device behavior, contribution in analog design and advanced NMOS technologies in the modern age.

NMOS Symbol: Comprehensive Guide to N Channel MOSFET Symbols, Operation and Applications

<h2 id="isPasted">Introduction</h2>Power electronics is evolving rapidly, with increasing demand for smarter, more efficient, and scalable power supply solutions. While digital control promises these capabilities, its adoption has been slow in the small-to-medium power range (50 W to 1 kW) due to the cost and power demands of conventional microcontrollers. As a result, analog control continues to dominate this segment, offering low cost and low power consumption but limited functionality.This article explores how ROHM’s Logic and Control Architecture (LogiCoA™) architecture addresses this long-standing challenge. By combining analog efficiency with digital flexibility, LogiCoA™ makes advanced digital control practical in the volume zone of industrial equipment. The sections that follow explain the limitations of existing solutions, introduce the hybrid approach behind LogiCoA™, and highlight the new possibilities it creates for cost, performance, and design flexibility.<h2>Challenges of Applying Digital Control to 50 W-1 kW Power Converters</h2>Microcontrollers for digitally controlled power supplies are not a novel concept - many semiconductor manufacturers have long offered solutions in this space, and they’re already integrated into a wide range of applications. What sets LogiCoA™ apart is its innovative approach to overcoming persistent limitations that conventional microcontrollers had yet to resolve.The issue lies in the fact that existing digital control microcontrollers are expensive and consume significant power. Consequently, they are primarily applicable to high-power areas in industrial equipment power systems, where the output exceeds 1kW. However, they are challenging to utilize in the small-to-medium power range of approximately 50 to 1kW, which represents the volume zone.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1756831854121-image4.jpg" style="width:100%px" class="fr-fic fr-dib" alt="power-control-industrial-segment" />Fig. 1: The segmentation of power control methods in industrial equipment power systems.Even in low to medium power range power systems, there is a strong demand to leverage the advanced functionalities unique to digital control power supplies. However, due to cost and power consumption issues, the adoption of digital control power supplies remains hesitant.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1756831881382-image3.jpg" style="width:100%px" class="fr-fic fr-dib" alt="analog-vs-digital-control-power-converters" />Fig. 2: Analog control relies on individual parts with low cost and power consumption but limited functionality, while digital control requires a high-speed microcontroller, leading to higher cost and power consumption despite enabling advanced functions.Table 1: Features of analog-controlled power supplies vs. digitally controlled power supplies.<div id="isPasted"><table><tbody><tr><td>Parameter</td><td>Analog Control</td><td>Digital Control</td></tr><tr><td>Cost</td><td>Excellent - No need for CPU </td><td>Neutral - Requires high-speed CPU/DSP (higher cost)</td></tr><tr><td>Power Consumption</td><td>Excellent - Low (Icc = 3mA to 5mA)</td><td>Negative - High (Icc = 100mA to 150mA)</td></tr><tr><td>Functions</td><td>Negative - Low functionality, cannot support complex functions</td><td>Excellent - Can add advanced features like calibration and log acquisition</td></tr></tbody></table></div><h2 id="isPasted">Revamping the Configuration of the PWM Control Loop </h2>The cost and power consumption issues that existing microcontrollers for digitally controlled power supplies faced were resolved by LogiCoA™ through the hybrid of analog and digital technologies. Generally, digitally controlled power supplies utilize A-D converters and CPU/DSPs to construct PWM control loops. To minimize the delay time within these control loops, high-speed A-D converters and high-performance CPU/DSPs are essential. However, this has been the main cause of high costs and significant power consumption. To address this, LogiCoA™ revamped the configuration of the PWM control loop. Instead of using high-speed A-D converters, it utilized external analog compensators, such as error amplifiers.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1756834321673-Logicoaarc.jpg" style="width:100%px" class="fr-fic fr-dib" />Fig. 3: The configuration of power systems using LogiCoA™.The processing of PWM control is executed by an analog-digital PWM control circuit consisting of built-in comparators and timers. Analog signals input from the analog compensators are used as triggers for high-resolution timers, allowing the duty cycle of PWM signals to be controlled on each clock signal cycle without involving the CPU. Since control is initiated upon receiving signal input from the analog compensators, this method is referred to as "event-driven."The impact of revising the PWM control loop configuration has been tremendous. Compared to using existing microcontrollers for digitally controlled power supplies, costs can be reduced to about one-third to one-fourth, and power consumption can drop to about one-thirtieth. This breakthrough has paved the way for applying digital control to power systems in the small-to-medium power range for industrial equipment.<h2>Equipped with logging and calibration functions</h2>While LogiCoA™ integrates a CPU on the IC, it takes a unique approach by excluding the CPU from the real-time PWM control loop calculations. Instead, the CPU operates in the background, handling tasks such as power supply startup and shutdown, input/output monitoring, current sensing, and managing external communications - based on user-defined software routines. This architecture improves efficiency and enables several advanced features that are characteristic of digitally controlled power supplies. The following sections highlight these distinctive capabilities:The first advantage is the ability to adapt to various power topologies through software modifications. Typically, analog-controlled power ICs only support a single topology, requiring power supply manufacturers to prepare numerous product variants, which increases the burden of inventory management. However, with LogiCoA™, a single device can accommodate multiple topologies, significantly reducing the challenges of inventory management.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1756831922564-image5.png" style="width:100%px" class="fr-fic fr-dib" alt="logicoa-mcu-data-logging" />Fig. 4: Analyzing log data collected from the LogiCoA™ MCU by a control PC makes it possible to monitor the operational status of both the application and power supply unit itself.Another key feature is the ability to finely adjust circuit elements using the calibration function. Circuit elements such as ICs, power devices, and transformers used in power systems often have variations in their characteristic values. As a result, circuit design must include sufficient margins relative to the ratings of each element. This leads to larger dimensions for circuit elements, higher voltage resistance requirements, and subsequently, larger and costlier power systems. By utilizing LogiCoA™’s calibration function, these variations can be fine-tuned - allowing for smaller margins and enabling the miniaturization and cost reduction of power systems.<h2>Real-time power control with ROHM’s RMOS</h2>The software side of LogiCoA™ is powered by ROHM’s proprietary real-time operating system, Real-time Micro Operating System (RMOS), which is provided free of charge. RMOS supports two “state transition control modules,” enabling simultaneous control of PFC circuits and DC-DC converters - or two DC-DC converters. To simplify development, sample code is available for various topologies, and operating parameters can be easily configured using an Excel-based tool. Local user support throughout Europe is handled by ROHM's Application and Technical Solution Center in Willich, near Düsseldorf, Germany. Additionally, a dedicated support division for LogiCoA™ in Japan is equipped to provide assistance. This ensures that users in Europe can adopt the technology with confidence.<h2>Conclusion</h2>LogiCoA™ represents a massive shift in digitally controlled power supply design. By offloading real-time PWM control to an analog-digital circuit and reserving CPU resources for background tasks, it achieves dramatic reductions in cost and power consumption without sacrificing functionality. Features such as topology reconfigurability, calibration, and log acquisition further enhance system performance while reducing design complexity and size.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1756831959118-image1.png" style="width:100%px" class="fr-fic fr-dib" alt="logicoa-reference-board-ml62q2035" />Fig. 5: LogiCoA™ solutions include the core LogiCoA™ MCU along with other ROHM components, which vary by power supply topology.Together with ROHM’s RMOS operating system and dedicated global support, LogiCoA™ provides a practical path to digital control in the critical 50 W to 1 kW power range. This hybrid approach bridges the gap between analog and digital control, and sets a new standard for scalable, efficient, and intelligent power management.Explore <a href="https://www.rohm.com/support/logicoa" target="_blank" rel="noopener noreferrer">ROHM’s LogiCoA™ solutions</a> and start designing today.＊LogiCoA™ is a trademark or registered trademark of ROHM Co., Ltd.This article was contributed to and edited by<a href="https://www.wevolver.com/profile/ravi.rao" target="_blank" rel="noopener noreferrer"> Ravi Rao.</a>

Conventional microcontrollers make digital control impractical in 50 W-1 kW power supplies due to cost and power demands. ROHMs LogiCoA™ overcomes this with a hybrid, event-driven design that adds calibration, logging, and software flexibility for efficient, scalable power electronics solutions.

Hybrid Analog-Digital Control for 50 W-1 kW Power Converters by ROHM's LogiCoA™

Zener diodes are unique semiconductor devices designed to operate in reverse bias and maintain a stable voltage. This article explains how a Zener diode works, from its quantum-tunneling breakdown mechanism to practical uses in voltage regulation and circuit protection.

How Does a Zener Diode Work? Theory, Operation & Practical Applications

Configurable power supplies combine the flexibility of custom designs with the speed and cost-efficiency of modular systems. By enabling tailored voltage, current, and control features, they help engineers address evolving requirements across industrial and medical applications.

Configurable Power Supplies by Sager Electronics and Advanced Energy: A Modular Approach to Power System Design

Protolabs

Synopsys Inc

power supplies

power supplies

ORGANIZATIONS.

SHAPING THE INDUSTRY.

Sager Electronics

TRACO POWER

Latest Posts

EMI Mitigation in High-Density Designs with Ultra-Thin Inductors and High-Current Ferrite Beads

NMOS Symbol: Comprehensive Guide to N Channel MOSFET Symbols, Operation and Applications

Hybrid Analog-Digital Control for 50 W-1 kW Power Converters by ROHM's LogiCoA™

How Does a Zener Diode Work? Theory, Operation & Practical Applications

Configurable Power Supplies by Sager Electronics and Advanced Energy: A Modular Approach to Power System Design