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Hardware Overview

Let's take a closer look at the MCP4275 DAC and other hardware on this Qwiic breakout.

MCP4725 Digital to Analog Converter​

The MCP4725 Digital to Analog Converter (DAC) is a 12-bit single-channel digital to analog converter IC. The MCP4725 has a supply voltage range of 2.7V to 5.5V (default supply voltage is 3.3V over Qwiic) and communicates over I2C. The I2C interface supports standard (100kHz), fast (400kHz) and high speed (3.4MHz) modes and the MCP4725 has two available I2C addresses selected by the A0 pin. This breakout routes the A0 pin to a jumper to set the address to 0x60 by default and is changed by adjusting the solder jumper.

The MCP4725 has on-board EEPROM that stores DAC register's code for the analog output. The EEPROM and DAC register are programmable, values stored in the EEPROM persist through resets, upon reset the DAC value resets to the stored EEPROM value. The full range of the 12-bit DAC is 0-4095, which corresponds to VSS (Ground) to VDD (3.3V). The equation for output voltage is (see datasheet pg. 19): VDD * (DAC Value / 4096). For complete information on the MCP4725 refer to the datasheet

Connections​

Qwiic Connectors​

The pair of Qwiic connectors on this board provide both power (@3.3V) as well as an I2C connection.

Plated Through-Hole Header​

The board also breaks out all of the MCP4725's pins to a 0.1"-spaced PTH header on the bottom of the board. This includes the DAC's power pins, I2C data and clock as well as the output voltage signal.

LED​

The sole LED on the DAC Breakout is a red Power LED to signify when the board is powered.

Solder Jumpers​

The DAC Breakout has three solder jumpers labeled LED, ADDR and I2C. The list below outlines the jumpers' functionalities, default states and any notes on their uses:

  • LED - The LED jumper completes the power LED circuit and is CLOSED by default. Open this jumper to disable the power LED.
  • ADDR - The ADDR jumper sets the MCP4725's I2C address and is CLOSED by default. The default I2C address is 0x60. Open this solder jumper to switch the address to 0x61.
  • I2C - The I2C jumper pulls the I2C lines (SDA/SCL) to 3.3V through a pair of 2.2kΩ resistors. Completely open this jumper to disable pullups on the I2C bus if necessary.

Board Dimensions​

This breakout matches the Qwiic 1" x 1" (22.5mm x 22.5mm) standard and has four mounting holes that fit a 4-40 screw.

Board Dimensions