{"title":"Adafruit ISO1540 Bidirectional I2C Isolator - STEMMA QT / Qwiic","handle":"adafruit-iso1540-bidirectional-i2c-isolator-stemma-qt-qwiic","url":"/products/adafruit-iso1540-bidirectional-i2c-isolator-stemma-qt-qwiic","description":"The Adafruit ISO1540 Bidirectional I2C Isolator provides full electrical isolation between two sides of an I2C bus, using the TI ISO1540 chip with 2500 V-RMS isolation. It's ideal for separating earth-grounded circuits, reducing noise, or protecting sensitive equipment in power monitoring setups.\n\nFully bidirectional with support for clock stretching and up to 1 MHz I2C clock rates, each side operates independently at 3V to 5.5V with its own power supply. STEMMA QT / Qwiic connectors on both sides allow solderless wiring, and green LEDs confirm power on each half.\n\nKey Features\n\n\n2500 V-RMS Isolation – Full galvanic isolation between I2C bus sides\n\nBidirectional I2C – Transparent data transfer in both directions with clock stretching support\n\nUp to 1 MHz I2C Clock – Standard, fast, and fast-mode plus compatible\n\n3V – 5.5V Per Side – Independent power and logic levels on each side\n\n±50 kV/µs Transient Immunity – Protection against high-speed voltage transients\n\n−40°C to +125°C Operating Range – Industrial temperature rating\n\nSTEMMA QT / Qwiic Connectors – One on each isolated side for solderless wiring\n\n10 kΩ Pull-ups – Built-in on both sides, connected to their respective VCC\n\nPower LEDs – Green LED on each side confirms power is connected\n\n\nSafety Certifications\n\n4242 V-PK isolation per DIN VDE V 0884-11:2017-01\n2500 V-RMS for 1 minute per UL 1577\nCSA approved per IEC 60950-1 and IEC 62368-1\nHBM ESD protection: 4 kV on all pins, 8 kV on bus pins\n\n\nIdeal For\n\nIsolating earth-grounded equipment from microcontroller I2C buses\nPower monitoring systems requiring galvanic isolation\nNoise reduction on I2C buses in electrically noisy environments\nSafety-critical applications requiring certified isolation\n\n\nPackage Contents\n\n1× Adafruit ISO1540 Bidirectional I2C Isolator Breakout\n1× Header Strip\n\n\n\nNote: Both sides must be independently powered for the isolator to function. STEMMA QT cables not included.\n\n\nResources\n\nAdafruit ISO1540 I2C Isolator Guide\n","vendor":"Adafruit","product_type":"physical","in_stock":true,"options":[],"variants":[{"id":3432,"title":"Default Title","sku":"AF-4903","price":17.46,"compare_at_price":0.0,"on_sale":false,"in_stock":true,"available_quantity":100,"option1":"Default Title"}]}