4.3 V Zener in a 2 W SMA package
The Microchip SMAJ4731E3/TR13 is a 4.3 V Zener diode rated for 2 W continuous power dissipation in the DO-214AC (SMA) surface-mount package. The 9 Ohms maximum Zener impedance at the test current means the regulation voltage shifts about 9 mV per mA of load change — a figure to budget when the diode is the shunt element in a rail or reference circuit. Reverse leakage is 10 µA maximum at 1 V reverse — low enough that it won't steal bias current from a high-impedance divider in a monitoring loop.
Package and board-fit note
Tape & Reel (TR) packaging feeds directly into pick-and-place lines; the reel quantity matches typical volume builds without a changeover mid-strip. Tolerance is ±10% — a 4.3 V nominal part regulates between 3.87 V and 4.73 V at the test current. If the downstream circuit needs tighter regulation (a 5% or 2% band), the SMAJ family includes Zener grades with those tolerances; this ±10% variant is the general-purpose choice for bias rails and clamp protection where the absolute voltage matters less than the clamp ceiling.