2sc4257.pdf datasheet:

Ordering number:EN2925ANPN Triple Diffused Planar Silicon Transistor2SC42571200V/30mA High-Voltage Amplifier,High-Voltage Switching ApplicationsFeatures Package Dimensions High breakdown voltage.unit:mm Small Cob.2010C Wide ASO.[2SC4257] High reliability (Adoption of HVP process).10.24.53.65.11.31.21 : Base0.80.42 : Collector1 2 33 : EmitterJEDEC : TO-220AB2.55 2.55EIAJ : SC-46SpecificationsAbsolute Maximum Ratings at Ta = 25CParameter Symbol Conditions Ratings UnitCollector-to-Base Voltage VCBO 1500 VCollector-to-Emitter Voltage VCEO 1200 VEmitter-to-Base Voltage VEBO 5 VCollector Current IC 30 mACollector Current (Pulse) ICP 100 mACollector Dissipation PC 1.75 WJunction Temperature Tj 150 CStorage Temperature Tstg 55 to +150 CElectrical Characteristics at Ta = 25CRatingsParameter