直插式 SN74LS221N 74LS221 DIP-16 HD74LS221P 多谐振荡器单稳态

SN74LS123NSR/148/157/175/221/244/245/240 贴片SOP16 中体5.2MM

BU4051BCF SN74LS221DBRE4 LTC6242CGN TSSOP16