STF21N90K5 MOS(场效应管) STF21N90K5/SADA STF21N90K5-VB STF21NM50A STF21NM50N STF21NM50N F21NM50N STF21NM50N TK18A50D STF21NM50N 其他被动元件 STF21NM60N STF21NM60N F21NM60N