The LTC4302-1/LTC4302-2 addressable I2C bus and SMBus compatible bus buffers allow a peripheral board to be inserted and removed from a live backplane without corruption of the bus. The LTC4302-1/LTC4302-2 maintain electrical isolation between the backplane and peripheral board until their VCC supply is valid and a master device on the backplane side addresses the LTC4302-1/ LTC4302-2 and commands them to connect. The LTC4302-1/LTC4302-2's ADDRESS pin provides 32 possible addresses set by an external resistive divider between VCC and GND. The LTC4302-1/LTC4302-2 work with supply voltages ranging from 2.7V to 5.5V. The SDA and SCL inputs and outputs do not load the bus lines when VCC is low.