SLASF08A December   2021  – May 2024 DAC43508 , DAC53508 , DAC63508

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configurations and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Electrical Characteristics
    6. 5.6  Timing Requirements: SPI
    7. 5.7  Timing Requirements: Logic
    8. 5.8  Timing Diagrams
    9. 5.9  Typical Characteristics: Static Performance
    10. 5.10 Typical Characteristics: Dynamic Performance
    11. 5.11 Typical Characteristics: General
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Digital-to-Analog Converter (DAC) Architecture
        1. 6.3.1.1 DAC Transfer Function
        2. 6.3.1.2 DAC Register Update and LDAC Functionality
        3. 6.3.1.3 CLR Functionality
        4. 6.3.1.4 Output Amplifier
      2. 6.3.2 Reference
      3. 6.3.3 Power-On Reset (POR)
      4. 6.3.4 Software Reset
    4. 6.4 Device Functional Modes
      1. 6.4.1 Power-Down Mode
    5. 6.5 Programming
      1. 6.5.1 Serial Peripheral Interface (SPI)
  8. 7 Register Map
    1. 7.1 DEVICE_CONFIG Register (address = 01h) [reset = 00FFh]
    2. 7.2 STATUS_TRIGGER Register (address = 02h) [reset = 0000h]
    3. 7.3 BRDCAST Register (address = 03h) [reset = 0000h]
    4. 7.4 DACn_DATA Register (address = 08h to 0Fh) [reset = 0000h]
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Programmable LED Biasing
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Programmable Window Comparator
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

6.3.3 Power-On Reset (POR)

The DACx3508 family of devices includes a power-on reset (POR) function that controls the output voltage at power up. After the VDD supply has been established, a POR event is issued. The POR causes all registers to initialize to default values, and communication with the device is valid only after a 5-ms delay, when VDD reaches DAC operating range. The default value for the DAC data registers is zero code. The DAC output remains at the power-up voltage until a valid command is written to a channel.

When the device powers up, a POR circuit sets the device to the default mode. The POR circuit requires specific VDD levels, as indicated in Figure 6-2, to discharge the internal capacitors and reset the device on power up. To trigger a POR, VDD must be less than 0.7 V for at least 1 ms. When VDD drops to less than 1.7 V but remains greater than 0.7 V (shown as the undefined region), the device does not reset successfully under all specified temperature and power-supply conditions. In this case, initiate a POR. When VDD remains greater than 1.7 V, a POR does not occur.

DAC43508 DAC53508 DAC63508 Threshold Levels for VDD POR CircuitFigure 6-2 Threshold Levels for VDD POR Circuit