ZHCSA11H May 2012 – September 2024 TCA9548A
PRODUCTION DATA
The TCA9548A is an 8-channel, bidirectional translating I2C switch. The controller SCL/SDA signal pair is directed to eight channels of target devices, SC0/SD0-SC7/SD7. Any individual downstream channel can be selected as well as any combination of the eight channels.
The device offers an active-low RESET input which resets the state machine and allows the TCA9548A to recover must one of the downstream I2C buses get stuck in a low state. The state machine of the device can also be reset by cycling the power supply, VCC, also known as a power-on reset (POR). Both the RESET function and a POR cause all channels to be deselected.
The connections of the I2C data path are controlled by the same I2C controller device that is switched to communicate with multiple I2C targets. After the successful acknowledgment of the target address (hardware selectable by A0, A1, and A2 pins), a single 8-bit control register is written to or read from to determine the selected channels.
The TCA9548A may also be used for voltage translation, allowing the use of different bus voltages on each SCn/SDn pair such that 1.8-V, 2.5-V, or 3.3-V parts can communicate with 5-V parts. This is achieved by using external pull-up resistors to pull the bus up to the desired voltage for the controller and each target channel.