Littelfuse Expands X4-Class Portfolio with 200 V, 480 A Ultra-Junction MOSFET in SMPD-X Package

New X4-Class device simplifies thermal design, boosts efficiency, and reduces part count in energy storage, charging, drone, and industrial applications.

ROSEMONT, Ill., December 15, 2025 — Littelfuse, Inc. (NASDAQ: LFUS), a diversified industrial technology manufacturing company empowering a sustainable, connected, and safer world, today announced the release of the MMIX1T500N20X4 X4-Class Ultra-Junction Power MOSFET. This 200 V, 480 A N-channel MOSFET features an exceptionally low on-state resistance (RDS(on)) of just 1.99 mΩ, enabling superior conduction efficiency, simplified thermal management, and improved system reliability in power-dense designs.

The MMIX1T500N20X4 utilizes a high-performance, ceramic-based, isolated SMPD-X package with topside cooling for optimal thermal management. Compared with existing state-of-the-art X4-Class MOSFET solutions, the device offers up to 2× higher current ratings and as much as 63% lower RDS(on), enabling engineers to consolidate multiple paralleled low-current devices into a single high-current solution.

Features and Benefits

• 200 V blocking voltage, ultra-low RDS(on) of 1.99 mΩ for minimized conduction losses.
• High current capability (ID = 480 A) reduces the number of parallel devices needed.
• Compact SMPD-X isolated package with 2500 V isolation and improved thermal resistance (Rth(j-c) = 0.14 °C/W).
• Low gate charge (Qg = 535 nC) reduces gate drive power requirements.
• Simplified thermal management with topside-cooled packaging.

Together, these features deliver higher power density, reduced component count, and easier assembly—resulting in more efficient, reliable, and cost-effective system designs.

Applications

The MMIX1T500N20X4 is ideally suited for:

• DC load switches
• Battery energy storage systems
• Industrial and process power supplies
• Industrial charging infrastructure
• Drones and vertical take-off and landing (VTOL) platforms

 “The new devices enable designers to consolidate multiple paralleled low-current devices into a single high-current device, simplifying the design and reducing component count,” said Antonio Quijano, Product Marketing Analyst at Littelfuse. “This enhances system reliability, streamlines gate driver implementation, and increases both power density and PCB area efficiency.”

Frequently Asked Questions (FAQs)

How does the MMIX1T500N20X4 MOSFET improve system efficiency compared to existing solutions?

The MMIX1T500N20X4 delivers an ultra-low RDS(on) of 1.99 mΩ with a 480 A current rating, reducing conduction losses and heat. Replacing multiple paralleled MOSFETs with a single device simplifies designs, lowers component count, and boosts overall system efficiency.

 What applications benefit most from this MOSFET?
This MOSFET is ideal for high-current, low- to moderate-voltage systems where efficiency and reliability are critical. Typical uses include DC load switches, battery energy storage, industrial power supplies, charging infrastructure, and drone or VTOL power electronics.

What thermal and packaging advantages does the SMPD-X design provide?
The high-performance, ceramic-based SMPD-X package offers excellent thermal resistance (Rth(j-c) = 0.14 °C/W) and 2500 VRMS isolation, enabling higher power density and safer operation. Its topside-cooled design simplifies thermal management, reduces system size, and enhances long-term reliability.

Availability

The MMIX1T500N20X4 is available in tube (20 pieces) or tape-and-reel format (160/reel). Submit sample requests through authorized Littelfuse distributors worldwide. For a listing of Littelfuse distributors, please visit Littelfuse.com.
For More Information
Additional information is available on the MMIX1T500N20X4 X4-Class Ultra-Junction Power MOSFET product page. Require technical support? Please visit the Littelfuse website or reach out directly to:

• Francois Perraud, Sr. Manager, Product Management MOS & IGBT (SBU) FPerraud@Littelfuse.com