The default I2C address is 0x4C.

Power Pins

• VIN - this is the power pin. Since the DAC chip uses 3-5 VDC to power the board, give it the same power as the logic level of your microcontroller - e.g. for a 5V micro like Arduino, use 5V.
  
• VREF - this is the voltage reference pin. 
• 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 connectors to dev boards with STEMMA QT connectors or to other things with various associated accessories

DAC Output

• + - The analog voltage output from the DAC.

Address Pin and Jumper

• A0 - The address pin for setting the I2C address. You can chain up to two of these boards together on one I2C bus. Leave this pin low for default I2C address 0x4C or tie it high for I2C address 0x4E.
• 0x4E Jumper - On the back of the board is the address jumper, labeled 0x4E. You can leave this jumper open (low) to keep the board on the default I2C address 0x4C. Solder the jumper closed (high) to change the I2C address to 0x4E.

LDAC Pin

• LDAC - The load DAC pin. Transfers the content of the input register to the DAC register. The pin is tied to ground, allowing the DAC to update when new data is written to the input register.

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.