MCP4728-E

The MCP4728-E is a quad-channel, 12-bit voltage output Digital-to-Analog Converter (DAC) from Microchip Technology with non-volatile EEPROM memory and an I2C-compatible serial interface. Its on-board precision output amplifier achieves rail-to-rail analog output swing, providing maximum dynamic range within the supply voltage. The key differentiator of the MCP4728 is its integrated non-volatile EEPROM, which stores DAC input codes, device configuration bits, and I2C address bits. This enables the DAC outputs to be available immediately after power-up with the saved settings, eliminating the need for the host controller to reconfigure the DAC on each power cycle. Each of the four channels can independently select between internal or external voltage reference. The internal 2.048V precision reference provides accurate and stable output voltages, with gain options of 1x (0 to 2.048V) or 2x (0 to 4.096V). Alternatively, each channel can use VDD as the reference for a 0 to VDD output range. The device supports individual power-down mode per channel, with typical power-down current of only 40 nA when all channels are powered down. The I2C interface supports Standard (100 kHz), Fast (400 kHz), and High-Speed (3.4 MHz) modes, offering flexibility for various system architectures. AEC-Q100 Grade 1 qualification ensures suitability for automotive applications. The ‘E’ suffix indicates the extended temperature range of -40°C to +125°C.

The MCP4728-E converts 12-bit digital values into proportional analog voltage outputs. The conversion architecture is based on a resistor-string (R-string) DAC topology, which provides inherent monotonicity and low glitch energy. Each channel has its own DAC register and output buffer amplifier. The I2C interface receives digital data from the host controller and loads it into the DAC registers. For normal operation, the digital value in the DAC register is converted to an analog voltage by the resistor string, then buffered by a precision output amplifier capable of driving moderate loads. The output amplifier features rail-to-rail operation, allowing the output to swing very close to both supply rails. Voltage reference selection is per-channel: internal reference mode uses the on-chip 2.048V bandgap reference, providing high accuracy and stability; external reference mode uses VDD as the reference, providing a full-supply output range. The gain setting (1x or 2x) is available only with the internal reference and is controlled by configuration bits in the DAC register. The EEPROM memory stores both the DAC code values and the I2C device address bits, and is programmed through I2C commands. An on-board charge pump generates the high voltages needed for EEPROM programming. The RDY/BSY pin provides status indication during EEPROM write operations. The LDAC pin synchronizes updates across multiple DAC channels or can be used to read/write the I2C address bits. A Power-on Reset (POR) circuit ensures reliable device initialization at power-up, loading the saved configuration from EEPROM into the DAC registers.

• Set point adjustment and offset trimming in industrial systems
• Sensor calibration and precision analog frontends
• Closed-loop servo control and motor speed control
• Low-power portable instrumentation and medical devices
• Programmable voltage and current sources
• Bias voltage adjustment for power amplifiers and RF circuits