{"title":"Adafruit PCA9546 4-Channel STEMMA QT / Qwiic I2C Multiplexer","handle":"adafruit-pca9546-4-channel-stemma-qt-qwiic-i2c-multiplexer","url":"/products/adafruit-pca9546-4-channel-stemma-qt-qwiic-i2c-multiplexer","description":"Need to use multiple I2C devices that share the same address? The PCA9546 4-Channel STEMMA QT / Qwiic I2C Multiplexer lets you connect up to four same-address I2C devices with completely solderless wiring. Five JST SH connectors (1 input + 4 outputs) make it plug-and-play with any STEMMA QT or Qwiic board.\n\nWrite a single byte to select the active channel (default address 0x70, adjustable to 0x70–0x77) and all subsequent I2C traffic is routed to that port. With eight possible multiplexer addresses, you could theoretically control up to 8 × 4 = 32 same-address devices on one I2C bus. Also available as a breadboard-friendly breakout version.\n\nKey Features\n\n\n4 Multiplexed I2C Channels – Route I2C traffic to any of four downstream STEMMA QT / Qwiic ports\n\n5 JST SH Connectors – 1 input + 4 outputs, all solderless STEMMA QT / Qwiic compatible\n\nConfigurable Address – Default 0x70, adjustable to 0x70–0x77 via solder jumpers for up to 8 multiplexers\n\nOnboard 3.3 V 500 mA Regulator – Level-shift all QT ports to 3 V when using a 5 V microcontroller (jumper selectable)\n\n3 V and 5 V Compatible – Works with any logic level\n\nBreadboard Breakout Pins – Also available for traditional wired connections\n\nMounting Holes – For permanent installation in enclosures or projects\n\nPower LED – Indicates the board has power\n\n\n\nTip: The PCA9546 is functionally identical to the TCA9546A — any example code or library for the TCA9546 or TCA9548 will work with this board.\n\n\nHow It Works\nYour microcontroller sends a command byte to the multiplexer's address (0x70 by default) specifying which downstream channel to activate. All subsequent I2C communication passes through to the selected channel. You can enable multiple channels simultaneously if needed.\n\nIdeal For\n\nUsing multiple identical STEMMA QT / Qwiic sensors on one I2C bus\nIsolating I2C bus segments to avoid address conflicts\nExpanding I2C capacity on address-limited projects\nSensor arrays and multi-sensor data logging\n\n\nPackage Contents\n\n1× Adafruit PCA9546 4-Channel STEMMA QT / Qwiic I2C Multiplexer, assembled\n\n\n\nNote: STEMMA QT cables and I2C devices are not included.\n\n\nResources\n\n\nI2C Multiplexer Learn Guide – Overview, wiring, and example code (compatible with PCA9546)\n\nWhat is STEMMA QT? – Introduction to the STEMMA QT connector system\n","vendor":"Adafruit","product_type":"physical","in_stock":true,"options":[],"variants":[{"id":1771,"title":"Default Title","sku":"AF-5664","price":7.98,"compare_at_price":0.0,"on_sale":false,"in_stock":true,"available_quantity":102,"option1":"Default Title"}]}