Littelfuse Unveils 600 W TVS Diodes for EV and Automotive Use

Littelfuse has released an SZSMF6L series of automotive-grade transient voltage suppression (TVS) diodes. Rated at 600 W, the devices could deliver 50% more peak power than the earlier SZSMF4L series while retaining the same compact SOD-123FL package. The company positions the series as a solution for protecting increasingly space-constrained automotive and electric vehicle electronics from high-energy voltage surges.

​Transient voltage suppression diodes. Image used courtesy of Littelfuse

The SZSMF6L Series

With EV architectures trending toward higher integration and zonal control, designers face tighter board space limits while still needing reliable surge protection. To this end, the SZSMF6L series extends protection headroom without requiring larger footprints.

The SZSMF6L Series provides a peak pulse power rating of 600 W under a 10/1000 µs waveform. Compared to the SZSMF4L, this constitutes a 50% increase in surge-handling capability while maintaining footprint compatibility. The series also supports unidirectional working peak reverse voltages from 5 V to 75 V, and bidirectional operation from 10 V to 75 V.

SZSMF6L Series 10/1000 µs Pulse Waveform. Image used courtesy of Littelfuse

Notable performance features include sub-nanosecond response times to minimize transient exposure, planar chip construction to achieve consistent clamping and low leakage current, and a high operating temperature tolerance up to 175°C for harsh environments. The devices also meet AEC-Q101 qualification and are PPAP capable for automotive-grade change control and traceability.

From an ESD perspective, the devices exceed 16 kV per Human Body Model Class 3 standards, which is valuable for protecting sensitive interfaces and sensors. Littelfuse claims the devices are best for automotive applications, including EV powertrain systems, battery management, onboard charging, power distribution units, body and zone controllers, and lighting.

Transient Voltage Suppression in Automotive

Transient voltage suppression is a necessary safety precaution for vehicle electronics designers. Automotive environments are rife with brief but intense voltage spikes, as transients can originate from inductive load switching, alternator load dumps, or external electrostatic discharge events. While such surges often last only microseconds, they can exceed normal operating voltages by several multiples and threaten permanent damage to semiconductors, sensors, and controllers.

A typical vehicle power bus. Image used courtesy of Vishay

TVS diodes offer a counter to these effects through their avalanche breakdown behavior. When they exceed a certain voltage, they clamp the surge to a safe threshold and redirect excess energy away from the protected circuitry. Known for fast response times (i.e., typically below one nanosecond), TVS diodes outdo slower protective devices, such as fuses or thermal protectors, which can’t react quickly enough to prevent damage.

However, automotive and EV systems present the unique challenge of balancing high surge handling with limited board space and elevated thermal stress. Where vehicle architectures migrate to zonal control, circuits require smaller, more reliable suppression components that still adhere to automotive qualification standards. High peak power ratings, low leakage currents, and stable clamping performance across temperature ranges are major attributes of modern TVS diode design.

Outlook and Availability

As electric drivetrains and zonal architectures expand across the industry, rugged transient suppression solutions will continue to rise. Devices like Littelfuse’s SZSMF6L series show how semiconductor packaging and process improvements are advancing surge-handling capability without increasing component size. The SZSMF6L series is available in tape-and-reel quantities of 5,000 through authorized Littelfuse distributors worldwide.