SBAS430F January   2009  – April 2018 DAC7568 , DAC8168 , DAC8568

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Block Diagram
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Electrical Characteristics
    3. 7.3 Timing Requirements
    4. 7.4 Typical Characteristics: Internal Reference
    5. 7.5 Typical Characteristics: DAC at AVDD = 5.5 V
    6. 7.6 Typical Characteristics: DAC at AVDD = 3.6 V
    7. 7.7 Typical Characteristics: DAC at AVDD = 2.7 V
  8. 8 Detailed Description
    1. 8.1 Functional Block Diagram
    2. 8.2 Feature Description
      1. 8.2.1  Digital-to-Analog Converter (DAC)
      2. 8.2.2  Resistor String
      3. 8.2.3  Output Amplifier
      4. 8.2.4  Internal Reference
      5. 8.2.5  Serial Interface
      6. 8.2.6  Input Shift Register
        1. Table 1. DAC8568 Data Input Register Format
        2. Table 2. DAC8168 Data Input Register Format
        3. Table 3. DAC7568 Data Input Register Format
      7. 8.2.7  SYNC Interrupt
      8. 8.2.8  Power-on Reset to Zero Scale or Midscale
      9. 8.2.9  Clear Code Register and CLR Pin
      10. 8.2.10 Software Reset Function
      11. 8.2.11 Operating Examples: DAC7568/DAC8168/DAC8568
        1. Table 4.   1st: Write to Data Buffer A:
        2. Table 5.   2nd: Write to Data Buffer B:
        3. Table 6.   3rd: Write to Data Buffer G:
        4. Table 7.   4th: Write to Data Buffer H and Simultaneously Update all DACs:
        5. Table 8.   1st: Write to Data Buffer C and Load DAC C: DAC C Output Settles to Specified Value Upon Completion:
        6. Table 9.   2nd: Write to Data Buffer D and Load DAC D: DAC D Output Settles to Specified Value Upon Completion:
        7. Table 10. 3rd: Write to Data Buffer E and Load DAC E: DAC E Output Settles to Specified Value Upon Completion:
        8. Table 11. 4th: Write to Data Buffer F and Load DAC F: DAC F Output Settles to Specified Value Upon Completion:
        9. Table 12. 1st: Write Power-Down Command to DAC Channel A and DAC Channel B: DAC A and DAC B to 1kΩ.
        10. Table 13. 2nd: Write Power-Down Command to DAC Channel H: DAC H to 1kΩ.
        11. Table 14. 3rd: Write Power-Down Command to DAC Channel C and DAC Channel D: DAC C and DAC D to 100kΩ.
        12. Table 15. 4th: Write Power-Down Command to DAC Channel F: DAC F to 100kΩ.
        13. Table 16. 1st: Write Sequence for Enabling the DAC7568, DAC8168, and DAC8568 Internal Reference All the Time:
        14. Table 17. 2nd: Write Sequence to Power-Down All DACs to High-Impedance:
        15. Table 18. 1st: Write Sequence for Disabling the DAC7568, DAC8168, and DAC8568 Internal Reference All the Time (after this sequence, these devices require an external reference source to function):
        16. Table 19. 2nd: Write Sequence to Write Specified Data to All DACs:
    3. 8.3 Device Functional Modes
      1. 8.3.1 Enable/Disable Internal Reference
        1. 8.3.1.1 Static Mode
          1. Table 20. Write Sequence for Enabling Internal Reference (Static Mode) (Internal Reference Powered On—08000001h)
          2. Table 21. Write Sequence for Disabling Internal Reference (Static Mode) (Internal Reference Powered On—08000000h)
        2. 8.3.1.2 Flexible Mode
          1. Table 22. Write Sequence for Enabling Internal Reference (Flexible Mode) (Internal Reference Powered On—09080000h)
          2. Table 23. Write Sequence for Enabling Internal Reference (Flexible Mode) (Internal Reference Always Powered On—090A0000h)
          3. Table 24. Write Sequence for Disabling Internal Reference (Flexible Mode) (Internal Reference Always Powered Down—090C0000h)
          4. Table 25. Write Sequence for Switching from Flexible Mode to Static Mode for Internal Reference (Internal Reference Always Powered Down—09000000h)
      2. 8.3.2 LDAC Functionality
      3. 8.3.3 Power-Down Modes
        1. 8.3.3.1 DAC Power-Down Commands
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications - Microprocessor Interfacing
      1. 9.2.1 DAC7568/DAC8168/DAC8568 to an 8051 Interface
        1. 9.2.1.1 Detailed Design Procedure
          1. 9.2.1.1.1 Internal Reference
            1. 9.2.1.1.1.1 Supply Voltage
            2. 9.2.1.1.1.2 Temperature Drift
            3. 9.2.1.1.1.3 Noise Performance
            4. 9.2.1.1.1.4 Load Regulation
            5. 9.2.1.1.1.5 Long-Term Stability
            6. 9.2.1.1.1.6 Thermal Hysteresis
          2. 9.2.1.1.2 DAC Noise Performance
          3. 9.2.1.1.3 Bipolar Operation Using The DAC7568/DAC8168/DAC8568
      2. 9.2.2 DAC7568/DAC8168/DAC8568 to Microwire Interface
      3. 9.2.3 DAC7568/DAC8168/DAC8568 to 68HC11 Interface
  10. 10Layout
    1. 10.1 Layout Guidelines
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Device Nomenclature
        1. 11.1.1.1 Static Performance
          1. 11.1.1.1.1  Resolution
          2. 11.1.1.1.2  Least Significant Bit (LSB)
          3. 11.1.1.1.3  Most Significant Bit (MSB)
          4. 11.1.1.1.4  Relative Accuracy or Integral Nonlinearity (INL)
          5. 11.1.1.1.5  Differential Nonlinearity (DNL)
          6. 11.1.1.1.6  Full-Scale Error
          7. 11.1.1.1.7  Offset Error
          8. 11.1.1.1.8  Zero-Code Error
          9. 11.1.1.1.9  Gain Error
          10. 11.1.1.1.10 Full-Scale Error Drift
          11. 11.1.1.1.11 Offset Error Drift
          12. 11.1.1.1.12 Zero-Code Error Drift
          13. 11.1.1.1.13 Gain Temperature Coefficient
          14. 11.1.1.1.14 Power-Supply Rejection Ratio (PSRR)
          15. 11.1.1.1.15 Monotonicity
        2. 11.1.1.2 Dynamic Performance
          1. 11.1.1.2.1  Slew Rate
          2. 11.1.1.2.2  Output Voltage Settling Time
          3. 11.1.1.2.3  Code Change/Digital-to-Analog Glitch Energy
          4. 11.1.1.2.4  Digital Feedthrough
          5. 11.1.1.2.5  Channel-to-Channel DC Crosstalk
          6. 11.1.1.2.6  Channel-to-Channel AC Crosstalk
          7. 11.1.1.2.7  Signal-to-Noise Ratio (SNR)
          8. 11.1.1.2.8  Total Harmonic Distortion (THD)
          9. 11.1.1.2.9  Spurious-Free Dynamic Range (SFDR)
          10. 11.1.1.2.10 Signal-to-Noise plus Distortion (SINAD)
          11. 11.1.1.2.11 DAC Output Noise Density
          12. 11.1.1.2.12 DAC Output Noise
          13. 11.1.1.2.13 Full-Scale Range (FSR)
    2. 11.2 Related Links
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

9.2.1.1.3 Bipolar Operation Using The DAC7568/DAC8168/DAC8568

The DAC7568, DAC8168, and DAC8568 are designed for single-supply operation, but a bipolar output range is also possible using the circuit in either Figure 128 or Figure 129. The circuit shown gives an output voltage range of ±VREF. Rail-to-rail operation at the amplifier output is achievable using an OPA703 as the output amplifier.

The output voltage for any input code can be calculated with Equation 4:

Equation 4. DAC7568 DAC8168 DAC8568 q_vout2_bas430.gif

Where:

DIN = decimal equivalent of the binary code that is loaded to the DAC register. It can range from 0 to 4095 for DAC7568 (12 bit), 0 to 16,383 for DAC8168 (14 bit), and 0 to 65535 for DAC8568 (16 bit).

n = resolution in bits; either 12 (DAC7568), 14 (DAC8168) or 16 (DAC8568)

Gain = 1 for A/B grades or 2 for C/D grades.

With VREFIN/VREFOUT = 5V, R1 = R2 = 10kΩ, for grades A and B.

Equation 5. DAC7568 DAC8168 DAC8568 q_vout3_bas430.gif

This result has an output voltage range of ±5V with 0000h corresponding to a –5V output and FFFFh corresponding to a +5V output for the 16-bit DAC8568, as shown in Figure 128. Similarly, using the internal reference, a ±2.5V output voltage range can be achieved, as Figure 129 shows.

DAC7568 DAC8168 DAC8568 ai_bipolar_ext_bas430.gifFigure 128. Bipolar Output Range Using External Reference at 5V
DAC7568 DAC8168 DAC8568 ai_bipolar_int_bas430.gifFigure 129. Bipolar Output Range Using Internal Reference