The BZT52B20-AQ is an SOD-123F-packaged, 20V rating, 0.5 Watt Zener Diode with 2% tolerance from the brand Diotec. It is a surge-rated, glass-passivated junction Zener diode which provides high tolerance tight limit, low noise, and low forward voltage drop for both low and high temperature operations. This diode offers low thermal resistance, excellent performance in pulses, and increased stability. It is suitable for high voltage rectification, welding machine, and automotive applications.