TVS protection for 30 V rails in a compact SMA footprint
The STMicroelectronics SMAJ30CA-TR is a bidirectional Zener-type transient voltage suppression diode from the SMAJ / TRANSIL™ series, designed to clamp overvoltage transients on 30 V nominal supply rails. It delivers 400 W peak pulse power per the 10/1000 µs waveform, with a breakdown voltage window starting at 33.3 V and a maximum clamping voltage of 64.3 V at the peak pulse current of 36 A (8/20 µs waveform).
400 W peak pulse power — sizing the protection for your rail
The 400 W rating (10/1000 µs) defines the energy the diode can absorb in a single pulse. For a 30 V rail, this translates to clamping a surge that would otherwise exceed the downstream IC's absolute maximum rating. The bidirectional configuration means a single device protects both positive and negative transients, which is useful on AC-coupled lines or where the polarity of the fault is unknown. The 36 A peak pulse current at the 8/20 µs waveform gives a real-world check for IEC 61000-4-5 surge testing at the equipment level.
This removes the sourcing risk of a last-time-buy or forced redesign mid-production.
Package and footprint — DO-214AC (SMA)
The DO-214AC (also designated SMA) is a standard JEDEC outline with a 2.6 mm body width and 4.6 mm length, requiring a PCB land pattern of approximately 3.0 mm × 2.0 mm per pad.