SGLS143D December   2002  – July 2019 TPS3820-Q1 , TPS3823-Q1 , TPS3824-Q1 , TPS3825-Q1 , TPS3828-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Schematic
      2.      Normalized Input Threshold Voltage vs Free-Air Temperature
  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 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Manual Reset (MR)
      2. 8.3.2 Active High or Active Low Output
      3. 8.3.3 Push-Pull or Open-Drain Output
      4. 8.3.4 Watchdog Timer (WDI)
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Supply Rail Monitoring with Watchdog Time-out and 200-ms Delay
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curve
      2. 9.2.2 Decoupling WDI During Reset Event
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
        1. 12.1.1.1 Related Links
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DBV|5
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.4 Watchdog Timer (WDI)

TPS3820/3/4/8-xx-Q1 devices have a watchdog timer that must be periodically triggered by either a positive or negative transition at WDI to avoid a reset signal being issued. When the supervising system fails to retrigger the watchdog circuit within the time-out interval, ttout, RESET becomes active for the time period td. This event also reinitializes the watchdog timer.

The watchdog timer can be disabled by disconnecting the WDI pin from the system. If the WDI pin detects that it is in a high-impedance state the TPS3820/3/4/8-xx-Q1 will generate its own WDI pulse to ensure that RESET does not assert. If this behavior is not desired place a 1-kΩ resistor from WDI to ground. This resistor will help ensure that the TPS3820/3/4/8-xx-Q1 detects that WDI is not in a high-impedance state.

In applications where the input to the WDI pin is active (transitioning high and low) when the TPS3820/3/4/8-xx-Q1 is asserting RESET, RESET will be stuck at a logic low after the input voltage returns above VIT–. If the application requires that input to WDI be active when the reset signal is asserted, then use a FET to decouple the WDI signal. An external FET decouples the WDI signal by disconnecting the WDI input when RESET is asserted. For more details on this, see Decoupling WDI During Reset Event for more details.