As system voltages creep upward, protection strategies that worked comfortably at 12 V or 24 V start to look less convincing. In data centres, network infrastructure, and industrial equipment, 48 V power architectures are now common, bringing higher energy levels and different failure modes when faults occur. In these environments, overvoltage events are rarely brief spikes. They are often longer switching surges, induced lightning transients, or sustained overvoltage conditions that sit uncomfortably close to DC. That is the space Toshiba is addressing with four new additions to its CUZ series of protection Zener diodes.
The CUZ56V, CUZ62V, CUZ68V, and CUZ75V extend the existing portfolio with Zener voltage options up to 75 V, specifically aimed at protecting semiconductor devices used on 48 V and higher supply rails. Rather than replacing transient voltage suppressors, these devices sit alongside them, filling a gap where longer-duration surge energy needs to be handled without sacrificing ESD robustness.
Protection Needs Change in 48 V Power Architectures
In lower-voltage systems, ESD is often the dominant concern. As supply voltages rise, the nature of the threat shifts. Switching surges, inductive kickback, and induced lightning events can last from microseconds into the millisecond range, carrying far more energy than a typical ESD strike. Standard TVS diodes are well suited to handling fast, high-voltage transients, but they are not always the best fit for these longer pulse conditions.
The CUZ series Zener diodes are designed to absorb and clamp these extended overvoltage events while still offering ESD protection. For engineers working on power entry stages, DC distribution rails, or protection networks around sensitive ICs, this provides another tool for managing fault energy without relying on oversized or inefficient solutions.
Electrical Characteristics Tuned for Surge Handling
Across the four new voltage variants, Toshiba has kept the core electrical capability consistent. Each device is rated for 600 mW of power dissipation and a peak pulse current of 5 A when tested under IEC61000-4-5 conditions with an 8/20 microsecond waveform. That standard is widely used to characterise surge immunity in industrial and infrastructure equipment, making the ratings directly relevant to real compliance scenarios.
Zener voltage ranges are specified at a test current of 2 mA, with the CUZ56V spanning 52 V to 60 V and the CUZ75V extending up to a maximum of 79 V. Dynamic resistance typically falls between 3.1 ohms and 4.0 ohms, which influences how sharply the device clamps as current rises. Typical clamp voltages are in the 112 V to 120 V range, reflecting the compromise between protection effectiveness and energy absorption capability that these applications demand.
ESD Robustness Without Separate Components
Although these devices are positioned primarily for surge protection, ESD performance has not been neglected. Contact discharge ratings range from plus or minus 13 kV for the lower voltage parts up to plus or minus 23 kV for the higher voltage variants, with 5 kV specified under air discharge conditions. For many designs, this level of ESD protection is sufficient to eliminate the need for an additional dedicated TVS device on the same node.
That consolidation can simplify layouts and reduce component count, which is particularly valuable in dense power distribution or interface circuitry where space and routing options are limited.
Packaging Choices for Dense, Inspectable Designs
All four devices are supplied in a SOD-323 package, measuring approximately 2.5 mm by 1.25 mm by 0.9 mm. The gull-wing leads support straightforward surface-mount assembly and provide good visibility for automated optical inspection. In high-volume manufacturing environments, especially those serving data centre and industrial markets, inspection reliability is a practical consideration rather than a secondary detail.
The use of a widely adopted package also supports drop-in replacement and easier adoption within existing designs, reducing the friction typically associated with adding new protection components.
Incremental Protection Improvements for Higher Reliability
The expansion of the CUZ series reflects a broader trend in power system design. As voltage levels rise, protection strategies become more nuanced. No single device can address every fault condition effectively. By extending Zener voltage options up to 75 V while maintaining strong surge and ESD performance, Toshiba is giving designers more flexibility to tailor protection networks to the realities of modern 48 V systems.
For engineers, the takeaway is straightforward. Protection is no longer just about surviving an ESD test. It is about managing sustained fault energy in systems where power levels continue to increase. Devices like these help close that gap without forcing a redesign of the entire protection architecture.
Learn more and read the original announcement at www.toshiba-semicon-storage.com
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