1500 W Zener TVS — clamping and standoff for 120 V rail protection
The 1.5SMC120A-M3/57T is a single-channel unidirectional Zener TVS diode from Vishay's 1.5SMC TransZorb® series.
Breakdown and clamping — what the ratings mean for circuit protection
For a 102 V nominal rail (e.g., a 100 VDC bus or a 120 VAC rectified line), this TVS prevents the voltage from rising above 165 V during a surge, protecting downstream semiconductors rated for 200 V or less. The 1500 W peak pulse rating at 10/1000 µs waveform means the device can absorb a 9.1 A pulse for 1 ms — sufficient for industrial surge environments per IEC 61000-4-5 if the source impedance is high enough to limit current.
The cathode band identifies the unidirectional orientation; the anode is the tab end. Standard SMC pad geometry with a 0.080-inch wide copper land per terminal is adequate for the 1500 W pulse energy.
The base product number is 1.5SMC120, and the -M3/57T suffix denotes the Tape & Reel packaging option for automated assembly.