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

Package Options

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

10.1 Layout Guidelines

A precision analog component requires careful layout, adequate bypassing, and clean, well-regulated power supplies.

The DAC7568, DAC8168, and DAC8568 offer single-supply operation, and are often used in close proximity with digital logic, microcontrollers, microprocessors, and digital signal processors. The more digital logic present in the design and the higher the switching speed, the more difficult it is to keep digital noise from appearing at the output.

As a result of the single ground pin of the DAC7568, DAC8168, and DAC8568, all return currents (including digital and analog return currents for the DAC) must flow through a single point. Ideally, GND would be connected directly to an analog ground plane. This plane would be separate from the ground connection for the digital components until they were connected at the power-entry point of the system.

The power applied to AVDD should be well-regulated and low noise. Switching power supplies and dc/dc converters often have high-frequency glitches or spikes riding on the output voltage. In addition, digital components can create similar high-frequency spikes as their internal logic switches states. This noise can easily couple into the DAC output voltage through various paths between the power connections and analog output.

As with the GND connection, AVDD should be connected to a power-supply plane or trace that is separate from the connection for digital logic until they are connected at the power-entry point. In addition, a 1μF to 10μF capacitor and 0.1μF bypass capacitor are strongly recommended. In some situations, additional bypassing may be required, such as a 100μF electrolytic capacitor or even a Pi filter made up of inductors and capacitors—all designed to essentially low-pass filter the supply and remove the high-frequency noise.