Texas Instruments TCA9849 1MHz 4-Channel I2C Multiplexer
Texas Instruments TCA9849 1MHz 4-Channel I2C Multiplexer is a 4-channel, bidirectional translating multiplexer that can be controlled through the I2C bus. The SCL/SDA upstream pair fans out to four downstream pairs, or channels. Any individual SCn/SDn channel, or combination of channels, can be selected, as determined by the contents of the programmable control register. These downstream channels can be used to resolve I2C target address conflicts. If four identical digital temperature sensors are needed in the application, one sensor can be connected to each channel (0-3), for example.
The system controller can reset the TCA9849 in the event of a time-out or other improper operation by asserting a low on the /RESET input. Similarly, the power-on reset initializes the I2C/SMBus state machine and deselects all channels. Asserting /RESET causes the same initialization and reset to occur without powering down the part. This allows recovery if one of the downstream I2C buses gets stuck in a low state.
The pass gates of the switches are configured so that the VDD1/VDD2 pins can be used to limit the maximum high-voltage level the Texas Instruments TCA9849 can pass. Limiting the maximum high voltage allows different bus voltages on each pair, so that 0.65V, 0.8V, 1.2V, or 1.8V parts can communicate with 3.3V parts without any additional protection. External pull-up resistors pull the bus up to the desired voltage level for each channel. Each I/O pin is 3.6V tolerant.
Features
- 1-to-8 bidirectional translating switches with ultra-low voltage translation down to 0.65V
- I2C Bus and SMBus compatible
- Active-low reset input
- Two address pins, allowing up to 16 TCA9849 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 0.65V, 0.8, 1.2V, 1.8V, 2.5V, and 3.3V
- No glitch on power-up
- Supports hot insertion
- Low standby current
- Operating power-supply VDD1 voltage range of 0.65V to 3.6V
- Operating power-supply VDD2 voltage range of 1.65V to 3.6V
- 3.6V-tolerant inputs
- 0 to 1MHz clock frequency
- Latch-up performance exceeds 100mA per JESD 78, class II
- ESD protection exceeds JESD 22
- ±2000V human-body model (A114-A)
- ±500V charged-device model (C101)
Applications
- Servers
- Routers (telecom switching equipment)
- Factory automation
- Products with I2C target address conflicts (such as multiple, identical temperature sensors)
Simplified Application Diagram
Development Tools
Texas Instruments TMUX-24PW-EVM Analog Switch Evaluation Module
The module allows for the quick prototyping and DC characterization of TI's line of TMUX products.
Texas Instruments TMUXBQB-DYYEVM Multiplexer Evaluation Module
Allows for the quick prototyping and DC characterization of TI's line of TMUX products.