The PCA9558 is a highly integrated, multi-function device that is composed of a 5-bit multiplexed/1-bit latched 6-bit I2C-bus/SMBus EEPROM DIP switch, an 8-bit I/O expander and a 2-kbit serial EEPROM with write protect. The PCA9558 integrates these commonly used components into a single chip to reduce component count and board space requirements and is useful in computer, server and telecom/networking applications.