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

8.1.1 Lower-Boundary Calculation

The lower boundary can be calculated based on the values listed in the Section 6.7 table. Additionally, facts must be taken into account to verify that the lower boundary is where it is expected. Because the internal oscillator of the window watchdog is running free, any rising edge at the WDI pin is taken into account at the next internal clock cycle. Accounting for any rising edge at the WDI pin occurs regardless of the external source. Because the shift between internal and external clock is not known, consider the worst-case condition when calculating this value.

Table 8-1 Watchdog Lower-Boundary Calculation
SELECTED OPERATION MODELOWER BOUNDARY OF FRAME
WDT = external capacitor C(ext)WDR = 0 Vtboundary,max = twindow,max / 23.5
tboundary,typ = twindow,typ / 25.8
tboundary,min = twindow,min / 28.7
WDR = VDDtboundary,max = twindow,max / 51.6
tboundary,typ = twindow,typ / 64.5
tboundary,min = twindow,min / 92.7