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16-Bit INA237 Qwiic Current and Power Sensor with 15 mOhm Shunt and Programmable Alerts
The SparkFun INA237 Qwiic Current Sensor is a precision DC and power-monitoring breakout based on the Texas Instruments INA237 digital power monitor. Using a 16-bit delta-sigma ADC, the board measures current, bus voltage, power, and internal temperature for an in-line DC load and communicates the measurement data over I2C. It includes a pre-installed 15 mOhm shunt resistor and is well-suited for power-supply monitoring, battery-powered systems, embedded electronics, and development projects requiring detailed electrical measurements.
The breakout provides 2x Qwiic connectors and a 3-pin screw terminal for convenient solderless integration, along with 0.1-inch spaced plated through-hole connections for power, SDA, SCL, and the multi-purpose alert output. Through-hole connections are also provided for using a custom external shunt resistor when the standard 15 mOhm value does not suit the application. Programmable conversion times from 50 us to 4.12 ms, hardware averaging from 1 to 1024 samples and threshold-based alerts allow the INA237 to handle measurement and monitoring tasks with reduced processing demand on the host microcontroller.
Key Features
- INA237 Power Monitor: Uses the Texas Instruments INA237 digital current and power-monitoring IC.
- 16-Bit ADC: Integrated 16-bit delta-sigma ADC supports precise electrical measurements.
- Multiple Measurements: Measures DC, bus voltage, power, and internal temperature.
- 15 mOhm Shunt Resistor: Includes a pre-installed 15 mOhm current-sense resistor for immediate use.
- Custom Shunt Support: Through-hole connections allow an external shunt resistor to be fitted for application-specific measurements.
- I2C Communication: Provides digital measurement data through an I2C interface for microcontroller integration.
- Qwiic Connectivity: Includes 2x Qwiic connectors for solderless connection to compatible Qwiic systems.
- Screw-Terminal Connection: 3-pin screw terminal provides a convenient connection point for the monitored DC power path.
- Through-Hole Interface: 0.1-inch spaced plated through-holes provide access to power, SDA, SCL, and alert connections.
- Programmable Alerts: Can generate alerts for configured voltage, current, power, and temperature thresholds.
- Conversion-Ready Alert: Alert output can indicate when a measurement conversion has completed.
- Fast Alert Response: Provides an alert response time of approximately 75 us.
- Selectable Conversion Time: ADC conversion time can be configured from 50 us to 4.12 ms.
- Hardware Averaging: Supports averaging from 1 to 1024 samples to balance response speed and measurement stability.
- Open-Drain Alert Output: Multi-purpose open-drain digital output supports event-driven monitoring.
- Processor Offloading: Hardware-based measurement, averaging, and threshold functions can reduce continuous processing requirements on the host controller.
Specifications:
INA237 Features
- 16-Bit Delta-Sigma ADC
- Current Monitoring Accuracy:
- Offset Voltage: ±50 µV (max)
- Offset Drift: ±0.02 µV/°C (max)
- Gain Error ±0.3% (max)
- Gain Error Drift: ±50 ppm/°C (max)
- Common Mode Rejection: 120 dB (max)
- Power Monitoring Accuracy: 1.6% full scale, -40°C to +125°C (max)
- Alert Response Time: 75 µS
- Common Mode Range: -0.3 V to +85 V
- Bus Voltage Sensing Input: 0 V to 85 V
- Shunt Full-Scale Differential Range: ±163.84 mV / ±40.96 mV
- 2.94MHz high-speed I2C interface.
- 4 Available I2C Addresses (Selected by solder jumpers)
- Default Address: 0x40
- Supply Voltage: 2.7 V to 5.5 V
- Operational Current: 640 µA (typ)
- Shutdown Current: 5 µA (max)
Qwiic Breakout Features
- 2x Qwiic Connectors
- 1x 3-Pin Screw Terminal
- Max Power Rating: 85V/10A
- IN± Shunt Resistor: 10mΩ (Default)
- Optional external shunt resistor connections
- VBUS isolated from IN± by default
- 0.1"-spaced Through Hole Header
- Power (VCC/GND), I2C (SDA/SCL) and Alert
- Red Power LED
Applications
- DC monitoring
- Power-consumption measurement
- Battery-powered systems
- Power-supply monitoring
- Embedded power management
- Development-board power analysis
- IoT power monitoring
- Robotics and motor-control systems
- Industrial electronics
- Energy-monitoring systems
- Prototype power measurement
- Over-current and over-voltage monitoring
- Temperature-aware power systems
- Low-power microcontroller applications
Dimensions
