SparkFun QwiicBus - MidPoint

The SparkFun QwiicBus MidPoint extends the range of your I²C bus using differential signaling over standard Ethernet cables. Based on the NXP PCA9615 IC, it converts I²C signals (SCL and SDA) into four differential signals, enabling reliable communication over distances up to 100 feet (30 m) while maintaining signal integrity.

The MidPoint connects between QwiicBus EndPoints via RJ-45 connectors and provides two Qwiic connectors for tapping into the I²C bus at any point along the chain. An onboard LMR33630 buck regulator can source up to 3A at 3.3V for higher-power devices.

Key Features

• PCA9615 Differential I²C Buffer – Extends I²C up to 100 ft over Ethernet cables
• 2× RJ-45 Connectors – Standard Ethernet cable connections for differential signaling
• 2× Qwiic Connectors – Tap into the I²C bus with Qwiic-compatible devices
• LMR33630 Buck Regulator – Up to 3A at 3.3V for powering attached devices
• No Protocol Conversion – Maintains native I²C protocol (no packetising into RS-485 or 1-Wire)
• Breadboard-Compatible – 0.1" header pins broken out

Specifications

• I²C Supply Voltage – 2.3–5.5V
• Differential Supply Voltage – 3–5.5V
• Buck Regulator Input – 3.6–36V

Ideal For

• Long-range I²C sensor networks
• Distributed sensor installations over Ethernet cabling
• Industrial and building automation with I²C devices

Resources

• QwiicBus Hookup Guide
• Schematic (PDF)
• Eagle Files
• PCA9615 Datasheet (PDF)
• LMR33630 Datasheet (PDF)
• Hardware GitHub Repository