What is Planar Technology?

In today’s advanced electronic systems, particularly in telecommunications, data centers, aerospace, automotive, and industrial automation, efficient, compact, and thermally optimized power conversion is a critical enabler of performance and profitability.

Power conversion sub-systems ensure that end-use equipment receives the precise electrical energy it needs. For example, 48V DC rails are typical in telecom infrastructure, while 3.3V to 12V DC outputs are common in servers, computers, and embedded systems. To ensure user safety and system protection, transformers are essential: they provide galvanic isolation from the AC mains (typically 230V or 120V, 50/60 Hz) and adapt voltage levels to match the application’s requirements.

In modern power electronics, the switching frequency of converters directly impacts the size and efficiency of the system. Higher frequencies allow for smaller magnetics, faster transient response, and better power density. In the past, limitations in switching devices (like silicon BJTs) restricted frequencies to below 20 kHz. However, with the widespread availability of power MOSFETs, GaN (Gallium Nitride), and SiC (Silicon Carbide) transistors, frequencies above 500 kHz and even into the MHz range are now common in high-performance systems.

At these elevated frequencies, conventional wire-wound transformers (often built on bobbins with wound enamel wire) face critical limitations:

• Unpredictable parasitic elements
• Excessive size
• Poor thermal performance
• Inefficient winding layouts that result in EMI and high leakage inductanc.

The Planar Magnetics Advantage

Planar transformers and inductors represent the next-generation solution for high-frequency, high-power-density applications. Their structure replaces traditional wound wire with pre-tooled copper conductors-either stamped copper (leadframes) or etched PCB windings-stacked between thin, wide ferrite cores. This geometry offers consistent, repeatable performance and superior thermal characteristics.

Key Benefits of Planar Magnetics

• High Efficiency: Up to 98% efficiency in well-optimized designs
• Ultra-Compact & Low Profile: Supports tight spaces and low-Z-height enclosures
• Exceptional Thermal Management: Broad surface area enables efficient conduction and convection cooling
• Wide Frequency Range: Operational from 50 kHz to 1 MHz, compatible with modern SMPS topologies
• Precision & Repeatability: All windings are tool-defined, offering consistent electrical performance and high production quality
• Low Leakage Inductance: Typically <0.2% for ungapped cores, reducing switching losses and EMI
• Topology Versatility: Suitable for all major switch-mode power supply architectures (Push-Pull, Half-Bridge, Full-Bridge, LLC, etc.)
• Multi-Output Capability: Configurable with multiple secondaries (1 to 7 windings)
• Power Range: Scalable from 5 Watts to over 300 kW
• Lightweight: As low as 15g per 100W of output power
• Low EMI Emissions: Compact magnetic paths and shielded layouts reduce interference
• Wide Operating Temperature: From –55°C to +200°C, ideal for harsh environments

Efficient and compact, planar technology supports the growing demand for reliable, high-density power solutions in a wide range of modern systems.