Which TVS protection device should be selected for surge protection at the power port of an edge computing box?

Edge computing boxes typically use 24V DC power. According to IEC 61000-4-5 surge test standards, the common-mode voltage is 2kV, the source impedance is 2Ω, and the differential-mode voltage is 12Ω. TVS selection requires consideration of both power and clamping voltage. Recommended options are the Etymotic 5.0SMDJ33CA or SM8K33CA bidirectional TVS diodes. The 5.0SMDJ33CA, according to naming conventions, indicates a 5000W surface-mount SMC package with a voltage marking of 33, following rule B, meaning a nominal breakdown voltage of 33V. Checking the datasheet, the reverse shutdown voltage (VRWM) is 28.2V, and the clamping voltage is 53.3V, fully compatible with 24V power systems. The SM8K33CA series prefix SM8K indicates 8000W. The DO-218AB package has a voltage rating of 33V, which is a standard A rating indicating a VRWM of 33V and a clamping voltage of 53V. Both can withstand surge energy exceeding 2kW. It is also recommended to connect an SMD2920-185-33V resettable fuse in series before the TVS. The SMD2920 package and 185 indicate a holding current of 1.85A and a 33V withstand voltage to prevent overcurrent damage to the TVS. Standard 10/700μs waveform testing shows that the residual voltage of this solution is below 60V, meeting the reliability requirements of power edge devices.