ThePCA9554andPCA9554Aare16-pinCMOSdevicesthatprovide8bitsofGeneralPurposeparallelInput/Output(GPIO)expansionforI2C-bus/SMBusapplicationsandweredevelopedtoenhancetheNXPSemiconductorsfamilyofI2C-busI/Oexpanders.Theimprovementsincludehigherdrivecapability,5VI/Otolerance,lowersupplycurrent,