SLVSD43C May   2015  – February 2019 TPS7B68-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Typical Application Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 Switching Characteristics
    7. 6.7 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 Device Enable (EN)
      2. 7.3.2 Adjustable Power-Good Threshold (PG, PGADJ)
      3. 7.3.3 Adjustable Power-Good Delay Timer (DELAY)
      4. 7.3.4 Undervoltage Shutdown
      5. 7.3.5 Current Limit
      6. 7.3.6 Thermal Shutdown
      7. 7.3.7 Integrated Watchdog
        1. 7.3.7.1 Window Watchdog (WTS, ROSC, FSEL and WRS)
        2. 7.3.7.2 Standard Watchdog (WTS, ROSC and FSEL)
        3. 7.3.7.3 Watchdog Service Signal and Watchdog Fault Outputs (WD and WDO)
        4. 7.3.7.4 ROSC Status Detection (ROSC)
        5. 7.3.7.5 Watchdog Enable (PG and WD_EN)
        6. 7.3.7.6 Watchdog Initialization
        7. 7.3.7.7 Window Watchdog Operation (WTS = Low)
        8. 7.3.7.8 Standard Watchdog Operation (WTS = High)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation With Input Voltage Lower Than 4 V
      2. 7.4.2 Operation With Input Voltage Higher Than 4 V
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input Capacitor
        2. 8.2.2.2 Output Capacitor
        3. 8.2.2.3 Power-Good Threshold
        4. 8.2.2.4 Power-Good Delay Period
        5. 8.2.2.5 Watchdog Setup
      3. 8.2.3 Application Curves
  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 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.3 Adjustable Power-Good Delay Timer (DELAY)

The power-good delay period is a function of the value set by an external capacitor on the DELAY pin before turning the PG pin high. Connecting an external capacitor from this pin to GND sets the power-good delay period. The constant current charges an external capacitor until the voltage exceeds a threshold to trip an internal comparator, and Equation 2 determines the power-good delay period:

Equation 2. TPS7B68-Q1 eq02-tDLY_SLVSD43.gif

where

  • t(DLY) is the adjustable power-good delay period
  • CDELAY is the value of the power-good delay capacitor
TPS7B68-Q1 pg-activ_SLVSD43.gif

NOTE:

V(PG_TH) falling = V(PG_TH) rising – V(PG_HYST).
Figure 22. Power Up and Conditions for Activation of Power Good

If the DELAY pin is open, the default delay time is t(DLY_FIX).