SBAS794E november   2018  – august 2023 DAC60501 , DAC70501 , DAC80501

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics
    6. 7.6  Timing Requirements: SPI Mode
    7. 7.7  Timing Requirements: I2C Standard Mode
    8. 7.8  Timing Requirements: I2C Fast Mode
    9. 7.9  Timing Requirements: I2C Fast-Mode Plus
    10. 7.10 Timing Diagrams
    11. 7.11 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 DAC Architecture
        1. 8.3.1.1 DAC Transfer Function
        2. 8.3.1.2 DAC Register Structure
        3. 8.3.1.3 Output Amplifier
      2. 8.3.2 Internal Reference
        1. 8.3.2.1 Solder Heat Reflow
      3. 8.3.3 Power-On-Reset (POR)
      4. 8.3.4 Software Reset
    4. 8.4 Device Functional Modes
      1. 8.4.1 Power-Down Mode
    5. 8.5 Programming
      1. 8.5.1 Serial Interface
        1. 8.5.1.1 SPI Mode
          1. 8.5.1.1.1 SYNC Interrupt
        2. 8.5.1.2 I2C Mode
          1. 8.5.1.2.1 F/S Mode Protocol
          2. 8.5.1.2.2 I2C Update Sequence
            1. 8.5.1.2.2.1 Address Byte
            2. 8.5.1.2.2.2 Command Byte
            3. 8.5.1.2.2.3 Data Byte (MSDB and LSDB)
          3. 8.5.1.2.3 I2C Read Sequence
    6. 8.6 Register Map
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Charge Injection
        2. 9.2.2.2 Voltage Droop
        3. 9.2.2.3 Output Offset Error
        4. 9.2.2.4 Switch Selection
        5. 9.2.2.5 Amplifier Selection
        6. 9.2.2.6 Hold Capacitor Selection
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

9.2.2 Detailed Design Procedure

A basic sample-and-hold circuit consists of a voltage source (DAC in this case), a switch, a capacitor, and a buffer. As the name implies, this circuit has two modes of operation: sample and hold. In sample mode, the switch is closed connecting the DAC output to the hold capacitor, CH. In hold mode, the switch opens, disconnecting the DAC output from CH. Thus, the final output is held to the sampled value because of the charge stored on hold capacitor CH. The output buffer is needed for delivering the required current. In a practical circuit, the switch leakage and the amplifier bias current make the capacitor drift from the stored value. Therefore, the sample-and-hold circuit must be refreshed, even if the DAC value does not change. The key design parameters of a sample-and-hold circuit are charge injection and voltage droop.