ADI LTC4308CMS8#PBF

The hot swappable, 2-wire bus buffer allows I/O card insertion into a live backplane without corruption of the data and clock busses. The buffer provides bidirectional buffering, keeping the backplane and card capacitances isolated. Negative offset from output to input allows communication between output bus devices with high ∀i and devices on the low voltage input side, where bus supplies can be as low as 0.9V. If SDAOUT or SCLOUT are low for 30ms, the buffer will automatically break the Input-Output connection. At this time the buffer automatically generates up to 16 clock pulses on SCLOUT in an attempt to free the bus. A connection will resume if the stuck bus is cleared. During insertion, the SDAOUT and SCLOUT lines are precharged to 1V to minimize bus disturbances. When driven high, the ENABLE input allows the buffer to connect after a stop bit or bus idle condition. Driving ENABLE low breaks the connection between SDAIN and SDAOUT, SCLIN and SCLOUT. READY is an open-drain output which indicates that the backplane and card sides are connected.

• Optimized for Low Voltage Systems Down to 0.9V
• Bidirectional Buffer with Stuck Bus Recovery
• –200mV Offset In-Out/+300mV Offset Out-In
• 30ms Stuck Bus Timeout
• Compatible with Non-Compliant ∀i I²C Devices
• Prevents SDA and SCL Corruption During Live Board Insertion and Removal from Backplane
• ±6kV Human Body Model (HBM) ESD Protection
• Isolates Input SDA and SCL Lines from Output
• Compatible with I²C, I²C Fast Mode and SMBus
• READY Open-Drain Output
• 1V Precharge on SDAOUT and SCLOUT Lines
• Small 8-Lead (3mm×3mm×0.75mm) DFN and 8-Lead MSOP Packages

• Live Board Insertion
• Servers
• Capacitance Buffer/Bus Extender
• RAID Systems
• ATCA