PTZTF Automotive Zener Diodes ROHM Semiconductor PTZTF Automotive Zener Diodes are AEC-Q101 qualified Zener Diodes optimized for automotive voltage regulation. The PTZTF Zener Diodes feature a 2.0V to 40.0V Zener voltage range and a 10mA to 40mA Zener current range. These devices exhibit a 4Ω to 25Ω Zener impedance range and 1000mW power dissipation.