SLFS083A July   2024  – October 2024 TLC3555-Q1

PRODMIX  

  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 Switching Characteristics
    7. 5.7 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 Monostable Operation
      2. 6.3.2 Astable Operation
      3. 6.3.3 Power-on Reset
      4. 6.3.4 Thermal Shutdown
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Applications
      1. 7.2.1 Missing-Pulse Detector
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
        3. 7.2.1.3 Application Curve
      2. 7.2.2 Pulse-Width Modulation
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
        3. 7.2.2.3 Application Curve
    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 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3.3 Power-on Reset

The TLC3555-Q1 includes a power-on reset feature, which holds the output high-impedance until the power-up is complete and the output flip-flop state machine has achieved a valid state. Previous generations of 555 timers lacked this feature, meaning the output state as the power supply ramped was unpredictable. The power-on reset of the TLC3555-Q1 asserts to hold the output in a high-impedance (Hi-Z) state during the ramp event. After the supply voltage has reached the minimum threshold, the power-on reset is released, and the state machine and logic table described in Table 6-1 apply. The RESET pin of the TLC3555-Q1 includes a weak pullup resistance to VDD, so if the RESET pin is not driven externally, the device exits the reset state after the power-on reset event is complete. The device then enters whatever state is dictated by the values of THRES, TRIG, and CONT.