TCA9548A Series
8-channel 1.65- to 5.5-V I2C/SMBus switch with reset & voltage translation
Manufacturer: Texas Instruments
Catalog
8-channel 1.65- to 5.5-V I2C/SMBus switch with reset & voltage translation
Key Features
• 1-to-8 Bidirectional translating switchesI2C Bus and SMBus compatibleActive-low reset inputThree address pins, allowing up to eight TCA9548A devices on the I2C busChannel selection through an I2C Bus, in any combinationPower up with all switch channels deselectedLow RON switchesAllows voltage-level translation between 1.8V, 2.5V, 3.3V, and 5V busesNo glitch on power upSupports hot insertionLow standby currentOperating power-supply voltage range of 1.65V to 5.5V5-V Tolerant inputs0 to 400kHz Clock frequencyLatch-up performance exceeds 100mA Per JESD 78, class IIESD Protection exceeds JESD 22±2000V Human-body model (A114-A)200V Machine model (A115-A)±1000V Charged-device model (C101)1-to-8 Bidirectional translating switchesI2C Bus and SMBus compatibleActive-low reset inputThree address pins, allowing up to eight TCA9548A devices on the I2C busChannel selection through an I2C Bus, in any combinationPower up with all switch channels deselectedLow RON switchesAllows voltage-level translation between 1.8V, 2.5V, 3.3V, and 5V busesNo glitch on power upSupports hot insertionLow standby currentOperating power-supply voltage range of 1.65V to 5.5V5-V Tolerant inputs0 to 400kHz Clock frequencyLatch-up performance exceeds 100mA Per JESD 78, class IIESD Protection exceeds JESD 22±2000V Human-body model (A114-A)200V Machine model (A115-A)±1000V Charged-device model (C101)
Description
AI
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.
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.
