Description

The CJMCU TCA9548A I²C 8-Channel Multiplexer Development Board is a powerful and flexible module designed to expand your I²C communication capabilities. It allows a single microcontroller (Arduino, ESP32, Raspberry Pi, STM32, etc.) to control up to eight separate I²C channels, solving the common issue of I²C address conflicts when using multiple identical sensors or modules.

At the heart of the board is the TCA9548A chip, an intelligent signal-routing IC that creates eight independent I²C buses from a single master. Each channel can be activated individually or in combination by writing to the device’s control register over the I²C interface. This gives you full control over how sensors or modules are accessed, making it ideal for complex systems, modular sensor arrays, and multi-device I²C setups.

The board operates over a wide voltage range of 1.65V to 5.5V and supports mixed-voltage environments. This makes it compatible with low-voltage logic (1.8V/3.3V) as well as 5V microcontrollers. The TCA9548A also supports hot-swapping of I²C devices, meaning you can plug or remove sensors on downstream channels without affecting the rest of the system. An active-low RESET pin allows you to reset the bus if a downstream device becomes unresponsive, improving system reliability.

With its compact design, simple interface, and powerful channel control, this multiplexer is perfect for robotics, IoT systems, scientific measurement setups, and any project requiring multiple I²C devices—especially when identical components share the same address.

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Key Features

• 8-channel bidirectional I²C multiplexer/switch

• Allows a single master to control 8 separate I²C buses

• Solves I²C address conflicts when using identical sensors

• Supports enabling one or multiple channels at once

• Compatible with I²C and SMBus protocols

• Active-low RESET pin for recovering from bus lockups

• 3 hardware address pins (A0, A1, A2) allowing 8 unique multiplexer addresses

• Wide operating voltage: 1.65V – 5.5V

• 5V-tolerant logic inputs

• Supports mixed voltage levels across channels

• Supports hot-plugging/hot insertion of downstream devices

• Low power consumption and very low standby current

• Compact CJMCU-style development board for easy integration

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Technical Specifications

• Chip: TCA9548A

• Number of Channels: 8 downstream I²C buses

• I²C Address Range: 0x70 – 0x77 (set using A0, A1, A2 pins)

• Operating Voltage: 1.65V – 5.5V

• Interface: Standard two-wire I²C (SCL & SDA)

• I²C Speed: Up to Fast Mode (≈ 400 kHz)

• Reset Pin: Active-low

• Power-Up State: All channels disabled by default

• Logic Compatibility: Supports 1.8V, 3.3V, and 5V systems

• Features: Voltage-level translation, channel isolation, hot-swap support

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Applications

• Multi-sensor systems requiring multiple identical I²C devices

• Robotics and automation systems

• Modular sensor hubs and distributed sensor networks

• IoT devices with multiple environmental sensors

• Data acquisition systems

• Projects requiring isolation of faulty or noisy I²C devices

• Expanding I²C capabilities on microcontroller projects

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Benefits

• Eliminates address conflict limitations in I²C

• Enables more organized, reliable multi-sensor wiring

• Ideal for compact or complex embedded systems

• Protects communication by isolating unstable I²C devices

• Easy to use and integrate with common development platforms

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Important Usage Notes

• Each downstream channel may require its own pull-up resistors depending on your sensors/modules.

• Channels are controlled by writing a single byte to the TCA9548A via I²C.

• Use the RESET pin to recover from bus lockups caused by downstream devices.

• For multiple multiplexers, configure different addresses using A0–A2 pins.