SBAS337E April   2005  – March 2018 DAC7811

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Block Diagram
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics: VDD = 5 V
    7. 6.7 Typical Characteristics: VDD = 2.7 V
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
      1. 7.4.1 Serial Interface
      2. 7.4.2 Input Shift Register
      3. 7.4.3 SYNC Interrupt (Stand-Alone Mode)
      4. 7.4.4 Daisy-Chain
      5. 7.4.5 Control Bits C3 to C0
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Unipolar Operation Using DAC7811
      2. 8.1.2 Bipolar Operation Using the DAC7811
      3. 8.1.3 Stability Circuit
      4. 8.1.4 Amplifier Selection
      5. 8.1.5 Programmable Current Source Circuit
    2. 8.2 Typical Application
      1. 8.2.1 Single Supply Unipolar Multiplying DAC
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resource
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.1.2 Bipolar Operation Using the DAC7811

The DAC7811, as a 2-quadrant multiplying DAC, can be used to generate a unipolar output. The polarity of the full-scale output IOUT is the inverse of the input reference voltage at VREF.

Some applications require full 4-quadrant multiplying capabilities or bipolar output swing. As shown in Figure 29, external op amp U3 is added as a summing amp and has a gain of 2X that widens the output span to 5 V. A 4-quadrant multiplying circuit is implemented by using a 2.5-V offset of the reference voltage to bias U3. According to the circuit transfer equation given in Equation 2, input data (D) from code 0 to full-scale produces output voltages of VOUT = –2.5 V to VOUT = +2.5 V

Equation 2. DAC7811 EQ2.gif

External resistance mismatching is the significant error in Figure 29.

DAC7811 Bipolar_Output_Circuit.gifFigure 29. Bipolar Output Circuit