SPRS288H May   2008  – October 2021

PRODMIX  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Timing Diagrams
    9. 6.9 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Input Voltage (VDD)
        1. 7.3.1.1 VDD Hysteresis
        2. 7.3.1.2 VDD Glitch Immunity
      2. 7.3.2 Implemented Window-Watchdog Settings
        1. 7.3.2.1 Timing Rules of Window-Watchdog
      3. 7.3.3 Watchdog Software Considerations
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Lower-Boundary Calculation
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Programming Window-Watchdog Using an External Capacitor
      3. 8.2.3 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 Device Support
      1. 11.1.1 Device Nomenclature
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support 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

7.3.2.1 Timing Rules of Window-Watchdog

After the reset of the supervisor is released, the lower boundary of the first WDI window is disabled. However, after the first WDI pulse low-to-high transition is detected, the lower boundary function of the window is enabled. All further WDI pulses must fit into the configured window frame.

The lower boundary of the watchdog window begins with the rising edge of the WDI trigger pulse. At the same time, all internal timers are reset. If an external capacitor is used, the lower boundary is impacted because of the different oscillator frequency. See the Section 8.2.2.1 section for additional details. Figure 7-3, especially the shaded boundary area, was prepared in a nonreal ratio scale to better visualize the description.

GUID-E59A5313-C88D-48E8-BE31-A9B17D229ACC-low.gifFigure 7-3 Timing Diagram