7.5 V Zener in SOT-23 — automotive-grade voltage reference or clamp
The BZX84B7V5LYFHT116 is a 7.5 V Zener diode in the SOT-23 surface-mount package, rated for 250 mW continuous power dissipation. The ±2% tolerance on the nominal voltage makes it suitable for precision clamping or reference circuits where a standard ±5% Zener would drift outside the design window. AEC-Q101 qualification means the part has passed the automotive-grade stress tests: high-temperature reverse bias, temperature cycling, and ESD robustness per the AEC-Q101 standard. This is the entry-level qualification for a discrete semiconductor used in an engine-control unit, transmission controller, or body-module power supply.
Reverse leakage and impedance — what they mean for the circuit
Reverse leakage is specified at 1 µA maximum at 5 V reverse voltage. For a 12 V automotive rail clamped by this Zener, the leakage at the operating point is well below 1 µA — negligible for a microcontroller supply or sensor bias line. The 15 Ohm maximum Zener impedance (Zzt) at the test current means the voltage drop across the diode changes by about 15 mV per mA of load current; a 1 mA load shift shifts the clamp voltage by 15 mV, which is within the ±2% tolerance band. The 150°C maximum junction temperature (TJ) rating matches the AEC-Q101 Grade 1 profile — the part can sit in an under-hood ambient of 125°C with self-heating margin. In a 250 mW dissipation scenario at 125°C ambient, the junction-to-ambient thermal resistance of the SOT-23 package (roughly 300°C/W) keeps the junction below 150°C as long as the board copper area provides adequate heat sinking.