The LTC4300A-3 hot swappable 2-wire bus buffer allows I/O card insertion into a live backplane without corruption of the data and clock busses. When the connection is made, the LTC4300A-3 provides bidirectional buffering, keeping the backplane and card capacitances isolated. Rise-time accelerator circuitry allows the use of weaker DC pull-up currents while still meeting rise-time requirements. During insertion, the SDA and SCL lines are precharged to 1V to minimize bus disturbances.The LTC4300A-3 provides level translation between 3.3V and 5V supplies. The backplane and card can both be powered with supplies ranging from 2.7V to 5.5V. The LTC4300A-3 also incorporates a CMOS threshold ENABLE pin which forces the part into a low current mode and isolates the card from the backplane. When driven to VCC, the ENABLE pin sets normal operation.The LTC4300A-3 is available in the MSOP and 3mm × 3mm DFN packages.*Patent pending.ApplicationsHot Board InsertionServersCapacitance Buffer/Bus ExtenderDesktop Computer