Description
Overview
The INA228 is a high-precision digital power monitor featuring a 20-bit delta-sigma ADC for accurate measurement of current and bus voltage. It supports both high-side and low-side DC current sensing and can measure bus voltages up to 85 V.
The module communicates with a microcontroller through I²C and can report current, bus voltage, power, energy, charge, and internal temperature. The STEMMA QT / Qwiic connectors provide a convenient plug-and-play interface for compatible development boards.
Key Features
- INA228 20-bit precision power monitor
- 20-bit delta-sigma ADC
- Measures DC current, bus voltage, power, energy and charge
- Supports high-side and low-side current measurement
- Bus voltage measurement up to 85 V
- I²C digital interface
- Compatible with STEMMA QT / Qwiic
- Programmable conversion time and averaging
- Integrated temperature sensor
- Alert output
- Wide 2.7–5.5 V supply range
- Suitable for 3.3 V and 5 V logic systems
Technical Specifications
| Parameter |
Specification |
| Main IC |
INA228 |
| ADC Resolution |
20-bit |
| Measurement Type |
Current / Voltage / Power / Energy / Charge |
| Bus Voltage Range |
0–85 V |
| Common-Mode Voltage |
−0.3 to +85 V |
| Shunt Differential Range |
±163.84 mV / ±40.96 mV |
| Current Offset |
±1 µV max. |
| Gain Error |
±0.05% max. |
| CMRR |
154 dB min. |
| Power Accuracy |
0.5% full scale max. |
| Energy / Charge Accuracy |
1.0% full scale max. |
| Digital Interface |
I²C |
| I²C Speed |
Up to 2.94 MHz |
| I²C Addresses |
16 selectable addresses |
| Supply Voltage |
2.7–5.5 V |
| Operating Current |
640 µA typ. |
| Shutdown Current |
5 µA max. |
| Operating Temperature |
−40°C to +125°C |
| Current Measurement |
High-side / Low-side |
| Temperature Sensor |
Integrated |
| Alert |
Programmable |
These are the specifications of the INA228 IC from Texas Instruments.
Current Measurement
The INA228 measures the voltage across an external or onboard shunt resistor and calculates the corresponding current digitally.
For a module using the commonly supplied 15 mΩ shunt resistor, the module can be configured for different current ranges. For example, the Adafruit STEMMA QT/Qwiic implementation specifies up to approximately 10 A in its high-current configuration or 2.75 A in its higher-resolution configuration.
Important: The maximum safe current of a particular module depends on its shunt resistor, PCB copper, connector, thermal conditions, and operating environment. Do not treat the 85 V rating as an 85 V/10 A continuous power rating.
Interface
The module uses I²C for communication with the host microcontroller.
Typical compatible platforms include:
- ESP32
- ESP8266
- Arduino
- STM32
- Raspberry Pi
- Other 3.3 V / 5 V I²C-compatible controllers
The STEMMA QT / Qwiic connectors provide a convenient 4-wire connection for VCC, GND, SDA and SCL.
Applications
- DC power monitoring
- Battery monitoring
- Solar power systems
- Power supply monitoring
- Embedded systems
- Robotics
- Motor current monitoring
- IoT devices
- USB/DC power monitoring
- Laboratory instruments
- Industrial control
- Energy measurement
- High-side current sensing
What’s Included
- 1 × INA228 20-bit Current/Voltage/Power Monitor Module
Notes
- The INA228 is designed for DC measurement; it should not be connected directly to AC mains or used as an AC current monitor.
- The 85 V specification refers to the supported bus/common-mode voltage, not the maximum voltage that can be applied arbitrarily to every module connection.
- The actual maximum measurable current depends on the module’s shunt resistor and thermal design.
- The module requires an appropriate shunt resistor for current measurement.
- The INA228 itself operates from 2.7–5.5 V, while the monitored bus can be substantially higher, up to 85 V within the device’s specified conditions.
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