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.