STMicroelectronics SM4T21AY Mounting Type: Surface Mount Package / Case: * Polarization: Unidirectional Power (watts): 400W Series: TRANSIL?„? Voltage - Breakdown: 20V Voltage - Reverse Standoff (typ): 18V Product Category: TVS Diodes - Transient Voltage Suppressors RoHS: yes Polarity: Unidirectional Channels: 1 Channel Factory Pack Quantity: 1 Termination Style: SMD/SMT Other Names: 497-10910-2