# SparkFun Current Sensor - INA237 (Qwiic)

**Type:** Product page · **SKU:** SEN-31437 · **Brand:** [Sparkfun](https://core-electronics.com.au/brands/sparkfun-australia)
**Page:** https://core-electronics.com.au/sparkfun-current-sensor-ina237-qwiic.html ([markdown](https://core-electronics.com.au/sparkfun-current-sensor-ina237-qwiic.html.md))

Monitor DC current, bus voltage, temperature and power over I²C with the INA237's 16-bit ADC, Qwiic connectors, screw terminal and alert output.

## Pricing

- **Price:** $16.95 (inc GST) — $15.41 AUD, exc GST

## Availability & dispatch

- Available with a lead time — expect dispatch between Aug 19 and Aug 25.

## Description

## Product Overview

The SparkFun INA237 Qwiic Current Sensor makes it easy to monitor DC current and power with high precision over I2C. This Qwiic breakout features the INA237 digital power monitor from Texas Instruments, which measures current, bus voltage, temperature, and power for an in-line DC input using a 16-bit delta-sigma analogue-to-digital converter (ADC).

### Solderless or Soldered Integration

The INA237 Current Sensor includes both a 3-pin screw terminal and a pair of Qwiic connectors to allow for a solderless power monitor setup using the [Qwiic ecosystem](https://core-electronics.com.au/catalogsearch/result/?q=Qwiic). A 15 mΩ shunt resistor comes pre-populated on the board, but SparkFun has also provided through-hole pins for a custom shunt resistor value if needed. This board shares the same physical design as SparkFun's INA228 breakout, with the specific version noted by the box in the top-left corner of the board.

For those who prefer a soldered connection, the breakout features a plated through-hole header with 0.1" (2.54mm) spacing that breaks out the INA237's power, communication pins (SDA/SCL), and alert pin. The alert pin is a multi-purpose open-drain digital output that can report when conversions complete or when the INA237 measures values beyond a defined threshold, such as over/under voltage (both shunt and bus), along with current, power, and temperature values exceeding defined thresholds. Regardless of the preferred wiring method, integrating high-precision power monitoring into a project is as straightforward as possible.

### Advanced Alerting and Measurement

The onboard INA237 has been specifically designed to offload heavy processing from the microcontroller and features a multi-purpose open-drain alert pin that can report when conversions complete or when measurements exceed user-defined thresholds. To get the most out of the code, the INA237 offers several programmable hardware features:

- **Threshold Alerts:** Triggers that instantly alert the user if voltage, current, power, or internal temperature values exceed programmed limits.
- **Fast Response:** A rapid 75 microsecond alert response time to protect sensitive electronics.
- **Flexible Sampling:** Selectable ADC conversion times from 50µs to 4.12ms and hardware averaging from 1 to 1024 samples.

By utilising these built-in hardware capabilities, the main processor can remain in a low-power sleep state until an actual power event requires its attention.

## Features & 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
- Through-Hole Header with 0.1" (2.54mm) Spacing 
    - Power (VCC/GND), I2C (SDA/SCL) and Alert
- Red Power LED

## Documentation

- [Schematic](https://cdn.sparkfun.com/assets/c/6/f/2/7/SparkFun_Qwiic_Current_Sensor_INA2XX.pdf)
- [KiCad Files](https://cdn.sparkfun.com/assets/c/f/e/a/5/SparkFun_Qwiic_Current_Sensor_INA2XX.zip)
- [Board Dimensions](https://cdn.sparkfun.com/assets/b/8/9/8/b/SparkFun_Qwiic_Current_Sensor_INA2XX.png)
- [Hookup Guide](https://docs.sparkfun.com/SparkFun_Qwiic_Current_Sensor_INA2XX/)
- [Datasheet](https://cdn.sparkfun.com/assets/9/e/b/c/f/ina237.pdf) (INA237)
- [SparkFun INA2XX Arduino Library](https://github.com/sparkfun/SparkFun_INA2XX_Arduino_Library)
- [GitHub Repository](https://github.com/sparkfun/SparkFun_Qwiic_Current_Sensor_INA2XX)

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/S/E/SEN-31437_ecommerce_1786087630483.jpg)