SLVS165N April   1998  – July 2022 TPS3820 , TPS3823 , TPS3824 , TPS3825 , TPS3828

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and 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 Electrical Characteristics for TPS3823A-33 only
    7. 7.7 Timing Requirements
    8. 7.8 Switching Characteristics
    9. 7.9 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
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
        1. 12.1.1.1 Spice Models
      2. 12.1.2 Device Nomenclature
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.2.1 Supply Rail Monitoring With Watchdog Time-Out and 200-ms Delay

The TPS3823A can be used to monitor the supply rail for devices such as microcontrollers. The downstream device is enabled by the TPS3823A once the voltage on the supply pin (VDD) is above the internal threshold voltage (VIT– + VHYS). The downstream device is disabled by the TPS3823A when VDD falls below the threshold voltage minus the hysteresis voltage (VIT–). The TPS3823A also issues a reset signal if the WDI input is not periodically triggered by a positive or negative transition at WDI. When the supervising system fails to retrigger the watchdog circuit within the time-out interval, ttout, RESET becomes active for the time period td.

Some applications require a shorter reset signal than the 200 ms that most of the TPS382x family provide. In these cases, the TPS3820 is a good choice because it has a delay time of only 25 ms. If an open-drain output is required, replace the TPS3823A with the TPS3828 (if the WDI input must be active while RESET is low, see Decoupling WDI During Reset Event). Figure 9-1 shows the TPS3823A in a typical application.

GUID-16646E0F-E5BB-4204-B191-7279C77D330C-low.gif Figure 9-1 Supply Rail Monitoring With Watchdog Time-Out