SN74LS540
SN74LS540DB
SN74LS540DBE4
SN74LS540DBG4
SN74LS540DBR
SN74LS540DBRE4
SN74LS540DBRG4
SN74LS540DW
SN74LS540DWE4
SN74LS540DWG4
19129491934(手机优先微信同号)