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

• 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 TCA9511A 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 capacitances 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.

When the I2C bus is idle, the TCA9511A can be put

into shutdown mode by setting the EN pin low,

reducing power consumption. When EN is pulled high,

the TCA9511A 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.