2. P4SMAJ28A_R1_00001 Substitution Conclusion The P4SMAJ28A_R1_00001 is a viable alternative to the original SMAJ28A TVS diode for its core performance. All published key parameters—28V stand-off voltage, 45.4V clamping voltage, 400W peak pulse power, etc.—are fully aligned with the original part. The shared DO-214AC (SMA) footprint guarantees PCB pad compatibility and equivalent fundamental surge protection functionality. The differences, again, are the change in manufacturer (now Panjit International Inc.) and the appended suffix "_R1_00001." This suffix likely denotes an internal revision or lot code specific to Panjit, which typically does not affect the published electrical characteristics. When substituting, attention should be paid to the new manufacturer's quality certifications (e.g., compliance with industry standards required for the target application) and whether this specific code implies any minor, non-specified changes, such as material or process optimizations. Provided the datasheet parameters match, direct replacement is acceptable.