Adafruit
Adafruit TCA4307 Hot-Swap I2C Buffer with Stuck Bus Recovery
The Adafruit TCA4307 Hot-Swap I2C Buffer protects your main I2C bus from glitches caused by hot-plugging STEMMA QT / Qwiic peripherals. I2C wasn't designed f...
The Adafruit TCA4307 Hot-Swap I2C Buffer protects your main I2C bus from glitches caused by hot-plugging STEMMA QT / Qwiic peripherals. I2C wasn't designed for hot-swapping, and plugging or unplugging at the wrong moment can hang the bus. This buffer sits between your controller and peripherals, isolating the bus during connect/disconnect events.
Connect the IN side to your controller (Arduino, Raspberry Pi, Feather, etc.) and any I2C sensors to the OUT side. The chip handles up to 400 kHz I2C and includes automatic stuck bus recovery — if SDA or SCL is held low for ~40 ms, it disconnects and sends up to 16 clock pulses to reset the stuck device.
Key Features
- TCA4307 I2C Buffer – Hot-swap protection for I2C peripherals
- Stuck Bus Recovery – Automatic disconnect and 16-pulse reset after ~40 ms timeout
- Up to 400 kHz – Standard and Fast mode I2C support
- 2.3–5.5V Logic – Wide voltage range for controller and peripherals
- EN Pin – Manually disconnect IN and OUT sides
- READY Pin – Indicates when peripheral is safely connected and ready for communication
- STEMMA QT / Qwiic – Solderless I2C connectors on both sides
Ideal For
- STEMMA QT / Qwiic projects with frequent sensor swapping
- Protecting I2C buses from hot-plug glitches
- Recovering from stuck I2C bus conditions
- Prototyping setups with multiple interchangeable sensors
Package Contents
- 1× TCA4307 hot-swap I2C buffer breakout (assembled and tested)
Jargon buster
Plain-language definitions for the technical terms used above.
- breakout
- A breakout is a small circuit board that makes a tiny or hard-to-solder component easier to connect to with standard pins. It matters because this OLED module can be wired into a microcontroller project without needing to solder directly to the display’s fine contacts.
- Hot-swap
- Hot-swap means changing or connecting a power source while the circuit is still running. It matters when you want a project to keep operating during battery changes, supply swaps, or plug-in power transitions.
- I2C
- I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
- Qwiic
- Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.
- READY pin
- A READY pin is a signal pin that changes state when the sensor has finished taking a measurement. It matters when your microcontroller needs to read data only after a fresh conversion is available, instead of guessing with delays.
- STEMMA
- A plug-and-cable connection system used on some maker electronics boards to make wiring simpler. If a product uses STEMMA, you need the matching cable or connector type to plug it in without soldering.
- STEMMA QT
- A small plug-in connector system for I2C boards that lets you connect compatible sensors and controllers without soldering. It matters because it can make wiring faster and less error-prone, especially when adding several small modules to a project.
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Related Tutorials
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