85V rail clamp in a DO-214AC package
The STMicroelectronics SMAJ85CA-TR is a bidirectional Zener-based transient voltage suppressor from the SMAJ TRANSIL™ series, designed to clamp overvoltage events on 85V nominal rails. The 94V minimum breakdown voltage and 178V maximum clamping voltage define the protection window for the downstream circuitry.
400W peak pulse — sizing the protection margin
For an 85V rail, this translates to a peak pulse current of 13A under the 8/20µs waveform condition. When sizing the protection for a given transient threat, the clamping voltage of 178V at that current sets the maximum voltage the load sees. Derating for ambient temperature above 25°C follows the standard power-derating curve for the SMA package.
The SMAJ family is a broad portfolio, so supply continuity through multiple distribution channels is the norm.
The DO-214AC (SMA) footprint is a standard surface-mount package compatible with reflow soldering profiles.