The TCA9548A has eight bidirectional translating switches that can be 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.
The system master can reset the TCA9548A in the event of a timeout 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/initialization to occur without powering down the part.
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. 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 pullup resistors pull the bus up to the desired voltage level for each channel. All I/O pins are 5-V tolerant.
Features
1-of-8 Bidirectional Translating Switches I2C Bus and SMBus Compatible Active-Low Reset Input Address by Three Hardware Address Pins for Use of up to Eight Devices Channel Selection Via I2C Bus Power-Up with All Switch Channels Deselected Low rON Switches Allows Voltage-Level Translation Between 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 1.65 V to 5.5 V 5-V-Tolerant Inputs 400-kHz Fast I2C Bus Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II ESD Protection Exceeds JESD 22 2000-V Human-Body Model (A114-A) 200-V Machine Model (A115-A) 1000-V Charged-Device Model (C101)