SBVS286B March   2017  – July 2025 TPS3851-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements
    7. 5.7 Timing Diagrams
    8. 5.8 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 RESET
      2. 6.3.2 Manual Reset MR
      3. 6.3.3 UV Fault Detection
      4. 6.3.4 Watchdog Mode
        1. 6.3.4.1 CWD
        2. 6.3.4.2 Watchdog Input WDI
        3. 6.3.4.3 Watchdog Output WDO
        4. 6.3.4.4 SET1
    4. 6.4 Device Functional Modes
      1. 6.4.1 VDD is Below VPOR ( VDD < VPOR)
      2. 6.4.2 Above Power-On-Reset, But Less Than VDD(min) (VPOR ≤ VDD < VDD(min))
      3. 6.4.3 Normal Operation (VDD ≥ VDD(min))
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 CWD Functionality
        1. 7.1.1.1 Factory-Programmed Timing Options
        2. 7.1.1.2 Adjustable Capacitor Timing
      2. 7.1.2 Overdrive Voltage
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Monitoring the 1.8V Rail
        2. 7.2.2.2 Calculating the RESET and WDO Pullup Resistor
        3. 7.2.2.3 Setting the Watchdog
        4. 7.2.2.4 Watchdog Disabled During Initialization Period
      3. 7.2.3 Glitch Immunity
      4. 7.2.4 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Device Nomenclature
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.1.1.1 Factory-Programmed Timing Options

If using the factory-programmed timing options (listed in Table 7-1), the CWD pin must either be unconnected or pulled up to VDD through a 10kΩ pullup resistor. Using these options enables high-precision, 15% accurate watchdog timing.

Table 7-1 Factory Programmed Watchdog Timing
INPUTSTANDARD AND EXTENDED TIMING WDT (tWD)UNIT
CWDSET1MINTYPMAX
NC0Watchdog disabled
NC1136016001840ms
10kΩ to VDD0Watchdog disabled
10kΩ to VDD1170200230ms