The INA237 and INA238 are completely code and hardware equivalent. The only difference is that the INA238 has better gain error and offset voltage than the INA237.
The default I2C address is 0x40.
Power Pins
- VIN - this is the power pin. It can be powered by 3V or 5V. Give it the same power as the logic level of your microcontroller - e.g. for a 5V micro like Arduino, use 5V.
- GND - common ground for power and logic.
I2C Logic Pins
- SCL - I2C clock pin, connect to your microcontroller's I2C clock line. This pin can use 3-5V logic, and there's a 10K pullup on this pin.
- SDA - I2C data pin, connect to your microcontroller's I2C data line. This pin can use 3-5V logic, and there's a 10K pullup on this pin.
- STEMMA QT - These connectors allow you to connect to development boards with STEMMA QT (Qwiic) connectors or to other things with various associated accessories.
Input Pins
The pins are in a low side measurement configuration by default. They are available along the bottom edge of the board and the terminal block on the top edge of the board.
- VIN+ - Positive input pin.
- VIN- - Negative input pin.
- VBUS - Bus voltage input pin.
To measure high-side, connect VIN+ to the highest project voltage, and VIN- to the load's highest potential. The VBUS jumper connects VIN+ and VBUS together by default for high-side measurements.
To measure low-side, cut the VBUS jumper. Then, connect VIN- to ground and VIN+ to your load's lowest potential. VBUS should connect to the highest project voltage, up to 85V.
VBUS Jumper
On the back of the board, above the VIN+ and VBUS terminal block pins, is the VBUS jumper. This jumper connects or disconnects VBUS from VIN+. When the jumper is closed (default), it configures the board for high side measurement. When the jumper is cut, it configures the board for low side measurement.
Power LED
- Power LED - In the upper left corner, above the STEMMA connector, on the front of the board, is the power LED, labeled on. It is the green LED.
Address Jumpers
On the back of the board are two address jumpers, labeled A0 and A1, above the Addr label on the board silk. These jumpers allow you to chain up to 4 of these boards on the same pair of I2C clock and data pins. To do so, you solder the jumpers "closed" by connecting the two pads. This pulls the pin high.
The default I2C address is 0x40.
The table below shows all possible addresses, and whether the pin(s) should be high (closed) or low (open).
Page last edited June 19, 2025
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