1 Features

• Supports bidirectional data transfer of I2C bus

signals

• Operating power-supply voltage range of 2.3 V to

5.5 V

• TA ambient air temperature range of

-40 °C to 125 °C

• Stuck bus recovery featuring automatic bus

recovery

• 1-V Precharge on all SDA and SCL lines prevents

corruption during live insertion

• Accommodates standard mode and fast mode I2C

devices

• Supports clock stretching, arbitration and

synchronization

• Powered-off high-impedance I2C pins

2 Applications

• Servers

• Enterprise Switching

• Telecom switching equipment

• Base stations

• Industrial automation equipment

3 Description

The TCA4307 is a hot-swappable I2C bus buffer

that supports I/O card insertion into a live backplane

without corruption of the data and clock lines. Control

circuitry prevents the backplane-side I2C lines (in)

from being connected to the card-side I2C lines (out)

until a stop command or bus idle condition occurs

on the backplane without bus contention on the card.

When the connection is made, this device provides

bidirectional buffering, keeping the backplane and

card capacitance isolated. During insertion, the SDA

and SCL lines are pre-charged to 1 V to minimize the

current required to charge the parasitic capacitance of

the device.

The TCA4307 has stuck bus recovery, which

automatically disconnects the bus if it detects either

SDAOUT or SCLOUT are low for about 40 ms. Once

the bus is disconnected, the device automatically

generates up to 16 pulses on SCLOUT to attempt to

reset the device which is holding the bus low.

When the I2C bus is idle, the TCA4307 can be put into

shutdown mode by setting the EN pin low, reducing

power consumption. When EN is pulled high, the

TCA4307 resumes normal operation. It also includes

an open drain READY output pin, which indicates that

the backplane and card sides are connected together.

When READY is high, the SDAIN and SCLIN are

connected to SDAOUT and SCLOUT. When the two

sides are disconnected, READY is low.