TheAT9548A is an octal bidirectional translating switch controlled via the I2C-bus. The SCL/SDA upstream pair fans out to eight downstream pairs, or channels. Any individual SCx/SDx channel or combination of channels can be selected, determined by the contents of the programmable control register.
An active LOW reset input allows theAT9548A to recover from a situation where one of the downstream I2C-buses is stuck in a LOW state. Pulling the RESET pin LOW resets the I2C-bus state machine and causes all the channels to be deselected as does the internal Power-on reset function.
The pass gates of the switches are constructed such that the VDD pin can be used to limit the maximum high voltage which will be passed by theAT9548A. This allows the use of different bus voltages on each pair, so that 1.8 V or 2.5 V or 3.3 V parts can communicate with 5 V parts without any additional protection. External pull-up resistors pull the bus up to the desired voltage level for each channel. All I/O pins are 6 V tolerant.

1-of-8 bidirectional translating switches
2C-bus interface logic; compatible with SMBus standards
Active LOW reset input
Three address pins allowing up to eight devices on the I2C-bus
Channel selection via I2C-bus, in any combination
Power-up with all switch channels deselected
Low Ron switches
Allows voltage level translation between 1.8 V, 2.5 V, 3.3 V and 5 V buses
No glitch on power-up
Supports hot insertion
Low standby current
Operating power supply voltage range of 2.3 V to 5.5 V
6 V tolerant inputs
0 Hz to 400 kHz clock frequency
ESD protection exceeds 2000 V HBM per JESD22-A114 and 1000 V CDM per JESD22-C101
Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
Three packages offered: SO24, TSSOP24, and HVQFN24

Typical Application