MCP4728 4-channel DAC: specs and pinout
A module built on the Microchip MCP4728, a quad 12-bit digital-to-analog converter with I2C control and on-chip EEPROM. Each channel has its own output, and settings can be saved so they return at power-up.
Specs
| Spec | Value | Source |
|---|---|---|
| Supply voltage (VDD) | 2.7 V to 5.5 V | source Features; Electrical Characteristics |
| Resolution and channels | 12-bit, 4 channels (VOUT A to D) | source Features |
| Output range | Internal 2.048 V reference: 0 V to 2.048 V (gain 1) or 0 V to 4.096 V (gain 2); with VDD as reference: 0 V to VDD | source Features |
| I2C device code and address | Device code 1100 plus address bits A2 A1 A0; factory default 000; address bits can be written to EEPROM | source 5.3 Device Addressing; Table 5-1 note 1 |
| I2C speed | 100 kHz, 400 kHz; high-speed mode needs VDD of 4.5 V to 5.5 V | source I2C Serial Timing Specifications |
| Supply current | 800 uA typical, 1400 uA max with all 4 channels on (VDD = 5.5 V) | source Electrical Characteristics |
| Maximum output load current | 24 mA per output amplifier | source Output Amplifier section; Electrical Characteristics |
| Operating temperature | -40 C to +125 C | source Temperature Ranges |
Power
| Value | Source | |
|---|---|---|
| Supply | 2.7 V to 5.5 V on VDD | source Electrical Characteristics |
| Current | 800 uA typical with all four channels active | source Electrical Characteristics |
Pinout
The pinout is the MCP4728 chip's (10-lead MSOP). The module board's header order, pull-up resistors, address selection and any output buffering are not covered by an official document.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| VDD (1) | Power supply | 2.7 V to 5.5 V | source Pin Function Table | |
| SCL (2) | I2C serial clock | source Pin Function Table | ||
| SDA (3) | I2C serial data | source Pin Function Table | ||
| LDAC (4) | Load DAC synchronisation input | Updates outputs together | source Pin Function Table | |
| RDY/BSY (5) | EEPROM ready/busy output | source Pin Function Table | ||
| VOUT A (6) | Channel A output | source Pin Function Table | ||
| VOUT B (7) | Channel B output | source Pin Function Table | ||
| VOUT C (8) | Channel C output | source Pin Function Table | ||
| VOUT D (9) | Channel D output | source Pin Function Table | ||
| VSS (10) | Ground | 0 V | source Pin Function Table |
Build with it
Project ideas for the MCP4728 4-channel DAC. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Four-channel LED brightness controller: Each output swings 0 V to VDD (at most 24 mA), so a resistor of a few hundred ohms or more per LED keeps current low. The ESP32's 3.3 V is inside the 2.7 V to 5.5 V supply range. Learning project.
- Adjustable voltage source with readout: The potentiometer sets a 12-bit code and the DAC outputs the voltage, shown on the OLED. On 3.3 V use gain 1 with the 2.048 V internal reference. Learning project.
- Programmable threshold tester: On 5 V the LM324 inputs must stay below about 3 V (VCC minus 2 V), so use the 2.048 V reference at gain 1 for the threshold and a divider on the potentiometer. Learning project.
Common mistakes
- Choosing gain 2 with the internal reference on a 3.3 V supply: the 0 V to 4.096 V range cannot be reached because the output swing is limited by VDD (source: link, Features; Electrical Characteristics)
- Drawing more than 24 mA from an output: the output amplifier is rated to 24 mA maximum load current (source: link, Output Amplifier section)
- Putting two MCP4728 chips on one bus without changing addresses: the factory address bits are 000 for every device (source: link, Table 5-1 note 1)
Not covered by the official source
- Module board (header order, pull-ups, address pin) not covered.
Sources
- link (MCP4728 datasheet DS22187E, Microchip, 2010)