Texas Instruments TCA9847PWR 1 MHz 8-Channel I2C Multiplexer

Introduction

The Texas Instruments TCA9847PWR is an 8-channel I2C/SMBus multiplexer designed to expand and organize I2C communication systems. It allows a single I2C controller to selectively communicate with up to eight downstream bus segments, making it useful when devices share the same I2C address or when a bus needs to be isolated for reliability.

Part Description

The TCA9847 is a bidirectional 1-to-8 I2C multiplexer with support for I2C and SMBus operation at clock rates up to 1 MHz. The device connects to an upstream controller through a primary SDA/SCL bus and provides eight selectable downstream channels.

A controller configures the active channel through I2C commands. Once selected, the corresponding downstream channel is connected to the upstream bus, allowing normal bidirectional communication with devices on that segment. This approach helps avoid address conflicts when multiple identical peripherals must be used in the same design.

The device supports voltage-level translation across a 0.65 V to 3.6 V operating range, enabling communication between logic domains with different supply voltages. Its active-low reset input can disconnect all channels and return the device to a known state, which is particularly useful for recovering from stalled or locked I2C bus conditions.

Key characteristics include:

• Eight selectable downstream I2C/SMBus channels
• Bidirectional I2C signal handling
• I2C and SMBus compatibility
• Clock frequency support up to 1 MHz
• Channel selection through the I2C bus
• Active-low reset input
• Voltage-level translation capability from 0.65 V to 3.6 V
• Useful isolation of I2C bus branches
• Texas Instruments TCA9847PWR package variant

Applications

Potential applications for the TCA9847PWR include:

• Systems using multiple I2C sensors with identical fixed addresses
• Multi-sensor environmental monitoring modules
• Embedded Linux single-board computer expansions
• Microcontroller-based data acquisition equipment
• Battery-management and power-monitoring networks
• Display, touch-controller, and user-interface subsystems
• I2C bus fault isolation and recovery designs
• Modular industrial control platforms
• Server and telecommunications management buses
• Medical and laboratory instrumentation

Industries

The TCA9847PWR can be used in a range of industries, including:

• Industrial automation
• Consumer electronics
• Internet of Things devices
• Automotive electronics
• Telecommunications
• Data-center and server infrastructure
• Healthcare and medical devices
• Test and measurement
• Robotics
• Smart building and energy-management systems

Usage Ideas

1. Eight-Location Temperature Monitoring System
   Connect identical I2C temperature sensors installed in different locations of an enclosure. Each sensor can occupy its own multiplexer channel, avoiding conflicts caused by shared default I2C addresses.

2. Modular Robotics Sensor Hub
   Build a robot control board that supports several interchangeable sensor modules, such as distance sensors, IMUs, and light sensors. The TCA9847 allows individual module buses to be selected and isolated.

3. I2C Fault-Recovery Controller
   Create a diagnostic controller for a complex embedded product with several I2C branches. If one peripheral branch becomes unresponsive, the controller can disconnect that channel, reset the multiplexer, and continue communicating with devices on other channels.

Conclusion

The Texas Instruments TCA9847PWR is a practical solution for expanding I2C and SMBus systems while managing address conflicts, bus segmentation, and fault recovery. With eight selectable channels, up to 1 MHz bus operation, voltage-level translation support, and an active-low reset function, it is well suited to compact embedded systems that need reliable communication with multiple I2C peripherals.