TI TCA4307DGKR

The TCA4307 is a hot-swap I2C bus buffer that supports insertion of I/O cards into a live backplane without corrupting data or disturbing clock lines. The control circuitry prevents the backplane-side I2C lines (inputs) from connecting to the card-side I2C lines (outputs) — until a Stop command or bus-idle condition occurs on the backplane — without causing bus contention on the card. Once the connection is established, the device provides bidirectional buffering, keeping the backplane and card capacitances isolated. During insertion, SDA and SCL lines are pre-charged to 1V, effectively reducing the current required to charge the parasitic capacitance of the device. The TCA4307 features stuck bus recovery functionality: when it detects SDAOUT or SCLOUT held low for approximately 40ms, it automatically disconnects the bus. After disconnection, the device automatically generates up to 16 pulses on SCLOUT to attempt to reset the device holding the bus low. When the I2C bus is idle, the TCA4307 can be placed into shutdown mode by driving the EN pin low, reducing power consumption. When EN is pulled high, the TCA4307 resumes normal operation. The device also includes an open-drain READY output pin that signals when the backplane and card sides are connected. When the READY pin is high, SDAIN and SCLIN are connected to SDAOUT and SCLOUT. When the two sides are disconnected, the READY pin is low.

• Bidirectional data transfer on I2C bus signals
• Operating supply voltage range: 2.3V to 5.5V
• TA ambient air temperature range: -40°C to 125°C
• Stuck bus recovery with automatic bus recovery
• 1V precharge on all SDA and SCL lines prevents damage during hot-board insertion
• Compatible with standard-mode and fast-mode I2C devices
• Supports clock stretching, arbitration, and synchronization
• Power-off high-impedance I2C pins

• Servers
• Enterprise switching
• Telecom switching equipment
• Base stations
• Industrial automation equipment