TC74VHC244FN TC74VHC244FS TC74VHC244FSEL TC74VHC244FS-EL TC74VHC244FT TC74VHC244FT(EKJ) TC74VHC244FT(EL TC74VHC244FT(EL) TC74VHC244FT(EL，K) TC74VHC244FT(EL,M)