Texas Instruments TCA9847 1MHz 8-Channel I2C Multiplexer

Texas Instruments TCA9847 1MHz 8-Channel I2C Multiplexer includes an SCL/SDA upstream pair that fans out to eight downstream pairs or channels. Any individual SCn/SDn channel can be selected, determined by the contents of the programmable control register. These downstream channels can be used to resolve I²C target address conflicts. One sensor can be connected to each channel (0-7) if eight identical digital temperature sensors are needed in the application.

If a time-out or other improper operation happens, the system controller can reset the Texas Instruments TCA9847 by asserting a low on the RESET input. The power-on reset also initializes the I²C/SMBus state machine and deselects all channels. Without powering down the part, a RESET causes the same reset and initialization to occur. 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 TCA9847 can pass. Limiting the maximum high voltage allows the use of 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. All I/O pins are 3.6V tolerant.

Features

1-to-8 bidirectional translating multiplexer 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 devices on the I²C bus
Channel selection through an I²C Bus
Power up with all switch channels deselected
Low R_ON 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 VDD2 voltage range of 1.65V to 3.6V
Operating power-supply VDD1 voltage range of 0.65V 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)