The Adafruit INA3221 breakout monitors current, voltage, and power on up to three independent power rails simultaneously over I2C. Each channel supports high or low-side measurement up to +26V DC at ±3.2A with ±1% precision — replacing the need for up to six multimeters in a multi-rail system.

With built-in 0.05Ω 1% sense resistors, a 13-bit ADC, and configurable over-current alert pins, this breakout is ready to go out of the box. Pre-attached 3.5 mm terminal blocks and STEMMA QT / Qwiic connectors mean you can wire up without soldering.

Key Features

• 3 Independent Channels – Monitor three power rails simultaneously from a single chip
• Up to +26V DC, ±3.2A Per Channel – High or low-side measurement with ±1% precision
• 13-bit ADC – 0.4 mA current resolution at ±3.2A range
• Built-in 0.05Ω Sense Resistors – 1% precision shunt on each channel, no external components needed
• Over-Current Alerts – Warning and critical IRQ pins for configurable current thresholds
• STEMMA QT / Qwiic Connectors – Solderless I2C connection with daisy-chain support
• Pre-Attached Terminal Blocks – 3.5 mm screw terminals for quick power rail hookup
• 3.3V & 5V Compatible – Works with Arduino, CircuitPython, Raspberry Pi, and more
• Customisable Range – Replace sense resistors to change current range (e.g., 0.01Ω for up to ±16.4A at 2 mA resolution)

Ideal For

• Multi-rail power supply monitoring and validation
• Battery and solar panel system profiling
• Embedded power consumption analysis across multiple subsystems
• Over-current detection with configurable alert thresholds

Package Contents

• 1× Adafruit INA3221 Triple Power Monitor Breakout (assembled)
• 3× 3.5 mm Terminal Blocks (pre-attached)
• 1× 0.1" Header Strip

Resources

• Adafruit INA3221 Guide
• STEMMA QT Overview