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Small green circuit board with black header pins and surface-mount chips

Adafruit

Adafruit TCA9548A I2C Multiplexer 1-to-8 engineering development tool

SKU CH-AX7A-WNX7K

Connects up to eight identical-address I²C devices to one microcontroller through a single multiplexer channel selectable by address 70 to 77

  • Product typeEngineering Development Tools
  • Connect up to eight identical I2C devices to one microcontroller
  • Operates at both 3 V and 5 V logic levels for broad compatibility
  • Simple single-byte register write selects the active channel
  • Multiplexer address configurable from 0x70 to 0x77 to avoid conflicts
  • TCA9548A chip routes I2C packets to the chosen output port

I2C multiplexer for microcontrollers

The Adafruit TCA9548A is a 1-to-8 I2C multiplexer that lets one microcontroller communicate with up to eight devices sharing the same fixed address. It operates at 3 V or 5 V logic levels, making it compatible with a wide range of development boards. The multiplexer itself sits at address 0x70, adjustable up to 0x77, so multiple boards can coexist on the same bus.

Integration into a project

The board requires only the two I2C lines plus power and ground from the host controller. Selecting a channel is done by writing a single byte to the multiplexer address, after which all subsequent I2C traffic is routed to that output. This frees the designer from address conflicts without adding extra microcontrollers or complex bus-switching circuitry.

Channel selection and address flexibility

Writing one byte to the multiplexer instantly redirects the bus to the chosen channel, simplifying firmware for multi-sensor arrays. The adjustable base address from 0x70 to 0x77 allows several multiplexers to share the same two-wire bus, expanding the total number of addressable devices well beyond eight.

How it compares

Measured against everything we stock in Engineering Workstations & Dev Kits, at today’s prices. Recalculated every night.

Price $9.99
Cheaper than about 56% of the 170 comparable items (median $11.49).

Specifications

Product
Product typeEngineering Development Tools

Questions about this item

How many I2C devices with identical addresses can the TCA9548A multiplexer connect to one microcontroller?

Up to eight same-address I2C devices can be connected through the 1-to-8 multiplexer channels.

What logic voltage levels does the TCA9548A board support for continuous operation?

The board is 3 V and 5 V compliant, so it works with either logic level without extra level shifting.

Which I2C address does the multiplexer itself use, and can it be changed if another device occupies that address?

The multiplexer defaults to address 0x70 and can be adjusted between 0x70 and 0x77 to avoid conflicts.

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