The LTC4301 supply independent, hot swappable, 2-wire bus buffer allows I/O card insertion into a live backplane without corruption of the data and clock busses. In addition, the LTC4301 allows the VCC, SDAIN and SCLIN pullup voltage and the SDAOUT and SCLOUT pull-up voltage to be independent from each other. Control circuitry prevents the backplane from being connected to the card until a stop bit or a bus idle is present. When the connection is made, the LTC4301 provides bidirectional buffering, keeping the backplane and card capacitances isolated.During insertion, the SDA and SCL lines are precharged to 1V to minimize bus disturbances. When driven low, the CS input pin allows the part to connect after a stop bit or bus idle occurs. Driving CS high breaks the connection between SCLIN and SCLOUT and between SDAIN and SDAOUT. The READY output pin indicates that the backplane and card sides are connected together.The LTC4301 is offered in 8-pin DFN (3mm × 3mm) and MSOP packages.ApplicationsHot Board InsertionServersCapacitance Buffer/Bus ExtenderDesktop ComputersCompactPCI™and ATCA Systems