Littelfuse DFNAK3 Compact TVS Diodes Handle 3 kA Surges

Littelfuse has introduced the DFNAK3 Series, a family of high-power TVS diodes rated for 3 kA (8/20 µs) surge events in a compact DFN surface mount package. The devices are designed for DC bus and Power over Ethernet (PoE) systems, where both surge robustness and board density are critical.

High Surge Protection in Less Space

Surge ratings of 3 kA have traditionally required axial-leaded or bulky coated surface-mount devices. By moving to a DFN format, Littelfuse has cut both footprint and height by about 70% compared to conventional coated parts. This allows protection circuits to fit into high-density boards without sacrificing performance.

That reduction can have a direct impact on layout in space-constrained designs such as remote radio units, baseband units, and compact PoE switches, where every square millimetre of PCB area is contested. For engineers balancing miniaturisation with reliability, this closes a long-standing gap between form factor and surge handling.

Jenny Chen, Product Marketing Manager at Littelfuse, explained, “The DFNAK3 Series enables compact, high-density system designs while delivering the same high surge rating as bulkier components, ensuring robust protection for mission-critical applications such as PoE, remote radio units, and data centre power supplies.”

Standards and Performance

The DFNAK3 diodes are designed to meet IEC 61000-4-5 Level 4 requirements. In practice, that means they can handle surges found in industrial and telecom environments without requiring multiple parallel devices. Their low clamping voltage provides stronger protection for downstream ICs than MOVs or GDTs, which often leave sensitive electronics exposed to higher let-through levels.

By using a breakdown voltage above the reverse standoff rating, the DFNAK3 maintains stability on DC lines while still reacting quickly to transient events.

Applications Beyond Telecom

Although aimed at PoE and telecom equipment, Littelfuse is also positioning the series for AI server racks, data centre power shelves, and industrial DC supplies where high surge capability must be paired with automated assembly. The surface mount DFN package integrates cleanly into reflow lines, reducing assembly cost compared to through-hole parts.

Availability

The DFNAK3 Series is available in tape-and-reel with quantities of 1,500 units. Samples can be ordered now through Littelfuse distribution partners.

Learn more and read the original article on www.littelfuse.com