1. Dynamic impedance (Zzt): The CMDZ5236B’s 6 Ω is significantly lower than the 15 Ω of the SZMM3Z7V5T1G. For a given change in operating current, the CMDZ5236B maintains a more stable Zener voltage, offering superior regulation. This is particularly beneficial in circuits sensitive to load variations or requiring a precise reference voltage. 2. Rated power: The SZMM3Z7V5T1G is rated at 300 mW, while the CMDZ5236B is rated at 250 mW. Substituting the part reduces the system power margin by 16.7%. The actual maximum power dissipation (Iz_max × Vz) in the application must be recalculated to ensure it remains well below 250 mW with adequate safety margin; otherwise, overheating and failure may occur. 3. Qualification and grade: The SZMM3Z7V5T1G is clearly marked “Automotive” and complies with AEC‑Q101. The CMDZ5236B carries no such designation. The former has passed automotive‑grade reliability tests (e.g., more stringent temperature cycling, humidity life tests) and is suitable for harsh environments such as automotive electronics. If the original design is intended for automotive use, downgrading to an unqualified device is not permissible. 4. Voltage tolerance: The CMDZ5236B offers ±5%, slightly better than the ±6% of the SZMM3Z7V5T1G. This gives the CMDZ5236B marginally higher initial voltage accuracy, though the difference is generally not critical for most regulation or protection circuits. 5. Reverse leakage current (Ir): Test conditions differ, but the measured values are close. The CMDZ5236B shows slightly higher leakage at a higher test voltage. Under high‑temperature, high‑reverse‑bias conditions, the CMDZ5236B may contribute somewhat higher static power dissipation, though this rarely affects circuit functionality.