View z1sma4728a-z1sma4764a series datasheet:

 SURFACE MOUNT 1SMA4728A-1SMA4764A ZENER DIODES VZ : 3.3 - 100Volts SMA (DO-214AC) PD : 1 Watt 1.1 ± 0.3 FEATURES : * Complete voltage range 3.3 to 100 volts * High peak reverse power dissipation * High reliability 0.2 ± 0.07 1.2 ± 0.2 * Low leakage current 2.1 ± 0.2 * Standard zener voltage tolerance is ± 5%. 2.6 ± 0.15 * Pb / RoHS Free MECHANICAL DATA 2.0 ± 0.2 * Case : SMA (DO-214AC) Molded plastic * Epoxy : UL94V-O rate flame retardant Dimensions in millimeter * Lead : Lead formed for Surface mount * Polarity : Color band denotes cathode end * Mounting position : Any * Weight : 0.064 gram MAXIMUM RATINGS Rating at 25 °C ambient temperature unless otherwise specified Rating Symbol Value Unit DC Power Dissipation at TL = 75 °C