Next-Gen Transient Voltage Protection: Exploring Semtech’s TVS Diodes in SOD-323 for Harsh Environments

In modern telecommunications and industrial automation systems, equipment is frequently deployed in challenging environments, exposing it to voltage transients that can originate from sources such as motor switching, powSWQ@e3er line fluctuations, indirect lightning strikes, electrostatic buildup, and human-induced Electrostatic Discharge (ESD)) events. These transients pose significant risks, ranging from data corruption to catastrophic system failures, leading to costly downtime and repairs. As industrial and telecom systems become increasingly interconnected, safeguarding sensitive electronics from ESD and other transient voltage events is crucial. Transient Voltage Suppression (TVS) diodes provide a robust first line of defense by rapidly diverting excess energy to ground, as illustrated in Figure 1, with sub-nanosecond response times to clamp voltage spikes and protect critical components. 

Basic requirements of protection in modern industrial and telecom applications  

低电容 

For high-speed applications in telecommunications and industrial control, one of the important parameters in a TVS diode is low capacitance. Low capacitance TVS diodes are crucial to maintain signal integrity while offering protection against electrical overstress (EOS) events, including ESD, EFT, and voltage surges. These low capacitance TVS diodes offer transient voltage protection without distorting incoming and outgoing signals, thus without significantly affecting signal performance.  

High surge capability 

The second important parameter required in these applications is high surge current capability. Deployed at vulnerable interface points such as I/O ports, bus connections, and power entry modules, these devices are expected to withstand high surge currents while clamping transient voltages well below component damage thresholds. Their compliance with rigorous surge standards like IEC 61000-4-5 and ESD standards like IEC 61000-4-2 makes them indispensable in harsh industrial settings where electrical noise, lightning-induced surges, and equipment-generated ESD pose constant threats to sensitive microcontrollers, ASICs, and communication interfaces that form the backbone of modern industrial control systems and telecommunications networks. 

Selection of package 

The performance and reliability of TVS diodes heavily depend on the choice of semiconductor packages, which must balance power handling, thermal dissipation, and form factor. Semiconductor packaging is the critical interface between integrated circuit “dies” and their electronic environments, providing essential protection from mechanical, environmental, and electrostatic threats while serving as the testing interface. These packages must excel across physical, electrical, thermal, and mechanical domains while meeting strict reliability standards and cost targets. For TVS diodes used in ESD protection, package selection significantly impacts performance, with options including Dual Flat No-lead (DFN), Small Outline Diode (SOD), Small Outline Integrated Circuit (SOIC), Small Outline Transistor (SOT), and Surface Mount A/B/C (SMA/B/C) packages—each optimized for specific application requirements, power handling capabilities, and space constraints, making package selection a crucial consideration for system reliability and performance. 

Semtech's specialized portfolio of low-capacitance, high-surge TVS diodes in the SOD-323 package format addresses these requirements specifically for industrial and telecommunications applications, offering superior protection solutions within compact design parameters. 

Semtech Introduces Advanced Low-Capacitance high surge TVS diodes in SOD-323 packages 

Semtech Corporation has expanded its TVS diodes portfolio shown in Figure 2, with the launch of the RClampxx01H and RClampxx21H series. Both the series offer multiple working voltage options from 3.3V to 36V providing comprehensive protection for interfaces ranging from GPIO to USB 2.0, audio ports, VBus lines and Ethernet connections.  With capacitance values ranging from as low as 1.7pF to 3.6pF typically, these devices maintain signal integrity on high-speed communication lines. Each part protects one high-speed data or power line. 

Figure 2. Semtech offerings of TVS diodes in SOD-323 package 

Engineered in a 2.5mm × 1.3mm SOD-323 package with a large cross-sectional area, these RClamp TVS diodes offer peak pulse currents from 14A to 36A (8/20μs waveform), providing ample protection against surge events (Figure 2). Available in both unidirectional and bidirectional configurations, the series fully complies with IEC 61000-4-2 (ESD) and IEC 61000-4-4 (EFT) standards. These parts offer desirable characteristics for board-level protection, including low operating voltage, no device degradation, and fast response time. The peak pulse current vs clamping voltage waveforms is shown in Figure 3. 

 Figure 3. Peak pulse current vs clamping voltage waveforms 

Table 1 lists the specifications of Semtech’s low capacitance, high surge TVS diodes in SOD-323 packages. Each voltage option in Table 1 has a unidirectional and a bi-directional solution. The low capacitance values shown in Table 1 make these components particularly valuable for high-frequency applications where engineers can implement robust transient protection without compromising signal quality or high-speed data transmission performance. At the same time, these parts can protect electronic circuits from dangerous ESD, EFT and surges as well. Figure 4 lists several applications where these RClampxx01H and RClampxx21H series parts can be used to protect them from transient voltage conditions. 

Table 1. Specification of RClampxx01H/21H TVS diodes in SOD-323 package 

The low capacitance values shown in Table 1 make these components particularly valuable for high-frequency applications where engineers can implement robust transient protection without compromising signal quality or high-speed data transmission performance. At the same time, these parts can protect electronic circuits from dangerous ESD, EFT and surges as well.  

Applications of RClampxx01H & RClampxx21H TVS diodes  

The RClampxx01H and RClampxx21H series TVS diodes from Semtech, housed in the SOD-323 package, provide versatile solutions for transient voltage protection across a wide range of applications, as depicted in Figure 4. These TVS diodes are ideal for safeguarding high-speed data interfaces such as USB 2.0, RS-232 and Ethernet connections in telecommunications equipment, ensuring signal integrity with their low capacitance (1.7–3.6 pF) while protecting against surges up to 36A (8/20 µs). In industrial automation, they can protect proximity sensors, I2C bus extenders, and keyboards in control systems, shielding sensitive microcontrollers from EFT and voltage spikes. In each case, the TVS diodes are strategically placed at the interface between external connectors and internal circuitry to clamp voltage spikes and divert surge energy away from critical components. This ensures the continued reliability of devices operating in industrial and telecommunication environments where exposure to ESD, EFT, and surges is common. Additionally, they are well-suited for VBus lines in power delivery systems, offering robust protection against overvoltage events in both consumer and industrial devices. Figure 4 showcases implementation examples for Semtech's RClampxx01H and RClampxx21H TVS diode series, though their protective capabilities extend far beyond these illustrated scenarios. These versatile components provide robust transient voltage protection across numerous additional applications in both industrial and telecommunications environments. 

Figure 4. Application diagrams of RClampxx01H and RClampxx21H parts 

结论 

As electronic systems in industrial and telecommunications environments face increasingly complex transient voltage threats, Semtech's RClampxx01H and RClampxx21H series in SOD-323 packages represent a significant advancement in circuit protection technology. These TVS diodes strike an optimal balance between the competing requirements of modern electronics: compact size, low capacitance for signal integrity, and robust surge handling capability. As industrial systems become more interconnected and telecommunications infrastructure continues to evolve, these compact yet powerful protection devices will play an increasingly vital role in safeguarding sensitive electronics from the transient voltage threats that could otherwise lead to costly downtime and repairs. By implementing Semtech's SOD-323 packaged TVS diodes at vulnerable interface points, engineers can deliver more reliable, resilient systems without compromising on form factor or signal performance—a critical advantage in today's electronic designs. 

To know more about these products, visit www.semtech.com 

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