SBVS303B March   2017  – February 2018 TPS3890-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Circuit
      2.      VITN Accuracy vs 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 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 User-Configurable RESET Delay Time
      2. 8.3.2 Manual Reset (MR) Input
      3. 8.3.3 RESET Output
      4. 8.3.4 SENSE Input
        1. 8.3.4.1 Immunity to SENSE Pin Voltage Transients
    4. 8.4 Device Functional Modes
      1. 8.4.1 Normal Operation (VDD > VDD(min))
      2. 8.4.2 Above Power-On-Reset But Less Than VDD(min) (VPOR < VDD < VDD(min))
      3. 8.4.3 Below Power-On-Reset (VDD < VPOR)
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 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 Device Nomenclature
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community 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

8.3.1 User-Configurable RESET Delay Time

The rising RESET delay time (tPD(r)) can be configured by installing a capacitor connected to the CT pin. The TPS3890-Q1 uses a CT pin charging current (ICT) of 1.15 µA to help counter the effect of capacitor and board-level leakage currents that can be substantial in certain applications. The rising RESET delay time can be set to any value between 25 µs (no CCT installed) and 30 s (CCT = 26 µF).

The capacitor value needed for a given delay time can be calculated using Equation 1:

Equation 1. tPD(r) (sec) = CCT × VCT ÷ ICT+ tPD(r)(nom)

The slope of Equation 1 is determined by the time that the CT charging current (ICT) takes to charge the external capacitor up to the CT comparator threshold voltage (VCT). When RESET is asserted, the capacitor is discharged through the internal CT pulldown resistor (RCT). When the RESET conditions are cleared, the internal precision current source is enabled and begins to charge the external capacitor and when the voltage on this capacitor reaches 1.22 V, RESET is deasserted. Note that in order to minimize the difference between the calculated RESET delay time and the actual RESET delay time, use a low-leakage type capacitor (such as a ceramic capacitor) and minimize parasitic board capacitance around this pin.