SLVSF13A March   2019  – August 2021 TL7700-SEP

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Sense-Voltage Setting
      2. 8.3.2 Sense-Voltage Hysteresis Setting
      3. 8.3.3 Output Pulse-Duration Setting
    4. 8.4 Device Functional Modes
  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 Receiving Notification of Documentation Updates
    2. 12.2 Support Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.3 Output Pulse-Duration Setting

Constant-current charging starts on the timing capacitor when the sensing-line voltage reaches the TL7700-SEP sense voltage. When the capacitor voltage exceeds the threshold level of the output drive comparator, RESET changes from a low to a high level. The output pulse duration is the time between the point when the SENSE-pin voltage exceeds the threshold level and the point when the RESET output changes from a low level to a high level. When the TL7700-SEP is used for system power-on reset, the output pulse duration, tpo, must be set longer than the power rise time. The value of tpo in seconds is:

Equation 3. tpo=CT ΔVCTICT

where:

  • CT is the timing capacitor in farads

  • ΔVCT is the change in voltage at the CT pin (1.5-V reference voltage)

  • ICT is the timing capacitor charge current (typically 15 µA)

There is a limit on the device response speed. Even if Ct = 0, tpo is not 0, but approximately 5 µs to 10 µs. Therefore, when the TL7700-SEP is used as a comparator with hysteresis without connecting Ct, switching speeds (tr/tf, tpo/tpd, and so forth) must be considered.