1 Features

• 1-to-8 Bidirectional translating switches

• I2C Bus and SMBus compatible

• Active-low reset input

• Three address pins, allowing up to eight

TCA9548A devices on the I2C bus

• Channel selection through an I2C Bus, in any

combination

• Power up with all switch channels deselected

• Low RON switches

• Allows voltage-level translation between 1.8V,

2.5V, 3.3V, and 5V buses

• No glitch on power up

• Supports hot insertion

• Low standby current

• Operating power-supply voltage range of

1.65V to 5.5V

• 5-V Tolerant inputs

• 0 to 400kHz Clock frequency

• Latch-up performance exceeds 100mA Per JESD

78, class II

• ESD Protection exceeds JESD 22

– ±2000V Human-body model (A114-A)

– 200V Machine model (A115-A)

– ±1000V Charged-device model (C101)

2 Applications

• Servers

• Routers (telecom switching equipment)

• Factory Automation

• Products with I2C target address conflicts (such as

multiple, identical temperature sensors)

3 Description

The TCA9548A device has eight bidirectional

translating switches that can be controlled through

the I2C bus. The SCL/SDA upstream pair fans out to

eight downstream pairs, or channels. Any individual

SCn/SDn channel or combination of channels can

be selected, determined by the contents of the

programmable control register. These downstream

channels can be used to resolve I2C target address

conflicts. For example, if eight identical digital

temperature sensors are needed in the application,

one sensor can be connected at each channel: 0-7.

The system controller can reset the TCA9548A in the

event of a time-out, or other improper operation by

asserting a low in the RESET input. Similarly, the

power-on reset deselects all channels and initializes

the I2C/SMBus state machine. Asserting RESET

causes the same reset and initialization to occur

without powering down the part. This allows recovery

if one of the downstream I2C buses get stuck in a low

state.

The pass gates of the switches are constructed so

that the VCC pin can be used to limit the maximum

high voltage, which is passed by the TCA9548A.

Limiting the maximum high voltage allows the use of

different bus voltages on each pair, so that 1.8V, 2.5V

or 3.3V parts can communicate with 5V parts, without

any additional protection. External pullup resistors

pull the bus up to the desired voltage level for each

channel. All I/O pins are 5V tolerant.