MCP4922 Converter: Circuit, Pinout, and Datasheet

The MCP4922 devices are 12-bit buffered voltage output Digital-to-Analog Converters (DACs), respectively. The devices are powered by a single 2.7V to 5.5V supply and have a Serial Peripheral Interface (SPI) that is compatible. By setting the Gain Selection Option bit to VREF or 2 * VREF, the user can set the device's full-scale range to VREF or 2 * VREF (gain of 1 of 2).

The SHDN pin can be used to turn off both DAC channels, or the Configuration register bits can be used to turn off each DAC channel independently. In Shutdown mode, the shutdown channel's internal circuits are turned down for power savings, and the output amplifier is set to present a known high resistance output load (often 500 kΩ).

Double-buffered registers are included in the devices, allowing synchronous updates of two DAC outputs through the LDAC pin. A Power-on Reset (POR) circuit is also included in these devices to ensure stable power up. The devices use a resistive string architecture, which has the benefits of minimal DNL error and quick settling. The expanded temperature range (+125°C) is given for these devices.

For consumer and industrial applications where signal calibration or correction (such as temperature, pressure, and humidity) is required, the devices provide high accuracy and low noise performance.

The MCP4922 devices come in three different packages: PDIP, SOIC, and TSSOP.

Pinout

Symbol

Footprint

3D Model

• MCP4922: Dual 12-Bit Voltage Output DAC

• Rail-to-Rail Output

• SPI Interface with 20 MHz Clock Support

• Simultaneous Latching of the Dual DACs with LDAC pin

• Fast Settling Time of 4.5 µs

• Selectable Unity or 2x Gain Output

• External Voltage Reference Inputs

• External Multiplier Mode

• 2.7V to 5.5V Single-Supply Operation

• Extended Temperature Range: -40°C to +125°C

Functional Block Diagram

The diagram shows how to create a single-supply voltage output from a dual 12-bit DAC with up to 24-bit resolution. It's only a voltage divider with a buffered output in this circuit.

Step 1: Determine the required resolution: 4.1V/1μV = 4.1x106 volts. Because 2²² =4.2x106, a resolution of 22 bits is required. This design can be attempted with the MCP4922 since DNL = ±0.75 LSb.

Step 2: Because the VOUTB of the DACB has a resolution of 1 mV, it only has to be "pulled" 1/1000 to match the 1 μV target. The program could adjust for DACB's DNL mistake by dividing VOUTA by 1000.

Step 3: If R2 equals 100Ω, R1 must equal 100 kΩ.

Step 4:As stated in the equation, the resulting transfer function is not perfectly linear.

Simple, Double-Precision DAC With MCP4922

• Set Point or Offset Trimming

• Precision Selectable Voltage Reference

• Motor Control Feedback Loop

• Digitally-Controlled Multiplier/Divider

• Calibration of Optical Communication Devices

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