Power


Figure 4: The TDS2261P.C offers versatile protection for 22 V systems where short- duration pulse currents reach 40 A. (Image source: Semtech)


Figure 2: The TDS5801P.C provides robust surge protection for lines operating at 58 V. (Image source: Semtech)


switching it on and diverting the transient current to ground.


By utilizing a FET-based switching mechanism with an ultra-low ON resistance, SurgeSwitch devices can achieve consistent clamping voltages across a wide range of operating temperatures and peak pulse currents. This enables the integration of USB- PD and PoE into more demanding industrial applications that require predictable surge protection to support deployments across a wide range of operating conditions.


Selecting the right TDS solution Selecting the right SurgeSwitch device primarily depends on the working voltage


of the application, as this determines the clamping voltage required for circuit protection. For higher voltages, the TDS5801P.C (Figure 2) protects one I/O or power line operating at 58 V, which is typical of PoE. This device is available in a 1.6 mm × 1.6 mm × 0.55 mm package for high levels of space optimization. The TDS5801P.C offers:


● Peak pulse power rating: 1,490 W at 8/20 μs


● Peak pulse current: 20 A at 8/20 μs ● Supply clamping voltage: 70.2 V (typ.) ● ESD clamping voltage: down to 4.4 V ● ESD voltage ratings: ™ Air: ±20 kV ™ Contact: ±15 kV


Figure 3: With a compact two-lead package, the TDS0521PW.C enables surge protection in space-constrained designs. (Image source: Semtech)


With a high


pulse power rating and low ESD clamping voltage, the TDS5801P.C TDS is suitable for outdoor PoE applications such as surveillance cameras, remote meters, and networking equipment, where adverse weather can heighten ESD. In these applications, the extended operating temperature range of -55°C to +125°C is also essential for maintaining consistent protection, regardless of seasonal conditions. In contrast, the TDS0521PW.C (Figure 3) provides a solution for 5 V working voltages used in Internet of Things (IoT) devices and VBUS lines for low-power USB-PD. To serve highly integrated devices, the TDS is available in a 1.6 mm × 1.0 mm × 0.55 mm package, with side-wettable flanks for flat mounting. Key specifications of the TDS0521PW.C


include: ● Peak pulse power rating: 412 W at 8/20 μs


● Peak pulse current: ™ 40 A at 8/20 μs ™ 8 A at 10/1000 μs


● Supply clamping voltage: 8.7 V (typ.) for 40 A pulse


● ESD voltage rating: ±30 kV (air and contact)


For sensitive, low-voltage equipment, this device provides excellent protection against high-level surge events, especially when connected to the primary power source during charging.


For similar protection at 22 V working voltages, the TDS2261P.C (Figure 4) is a TDS suitable for mid-range USB-PD applications such as industrial tablet PCs. The TDS2261P.C offers: ● Peak pulse power rating: 1120 W at 8/20 μs


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● Peak pulse current: ™ 40 A at 8/20 μs ™ 3 A at 10/1000 μs


● Supply clamping voltage: 27.7 V (typ.) for 40 A pulse


● ESD voltage ratings: ™ Air: ±30 kV ™ Contact: ±20 kV


Despite being the largest of the SurgeSwitch devices, measuring 2 mm × 2 mm × 0.75 mm, the TDS2261P.C still offers a compact solution for high EOS and ESD protection in space-constrained devices. In addition to USB-PD, other target applications include storage devices and industrial sensors.


Conclusion


As USB-PD and PoE standards continue to expand power delivery performance, robust surge protection becomes challenging in highly integrated device designs. The Semtech SurgeSwitch series overcomes design challenges with clamping voltages that remain consistent across a wide range of temperatures and pulse currents. They also provide reliable protection from harsh power anomalies across different line voltages and operating conditions.


https://www.digikey.co.uk/ Components in Electronics March 2026 23


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