SLVS074I January   1983  – July 2022 TL494

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Simplified Block Diagram
  5. 5 Revision History
  6. 6 Pin Configuration and 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, Reference Section
    6. 7.6  Electrical Characteristics, Oscillator Section
    7. 7.7  Electrical Characteristics, Error-Amplifier Section
    8. 7.8  Electrical Characteristics, Output Section
    9. 7.9  Electrical Characteristics, Dead-Time Control Section
    10. 7.10 Electrical Characteristics, PWM Comparator Section
    11. 7.11 Electrical Characteristics, Total Device
    12. 7.12 Switching Characteristics
    13. 7.13 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 5-V Reference Regulator
      2. 9.3.2 Oscillator
      3. 9.3.3 Dead-time Control
      4. 9.3.4 Comparator
      5. 9.3.5 Pulse-Width Modulation (PWM)
      6. 9.3.6 Error Amplifiers
      7. 9.3.7 Output-Control Input
      8. 9.3.8 Output Transistors
    4. 9.4 Device Functional Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Input Power Source
        2. 10.2.2.2 Control Circuits
          1. 10.2.2.2.1 Oscillator
          2. 10.2.2.2.2 Error Amplifier
          3. 10.2.2.2.3 Current-Limiting Amplifier
          4. 10.2.2.2.4 Soft Start and Dead Time
        3. 10.2.2.3 Inductor Calculations
        4. 10.2.2.4 Output Capacitance Calculations
        5. 10.2.2.5 Transistor Power-Switch Calculations
      3. 10.2.3 Application Curves for Output Characteristics
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 Feedback Traces
      2. 12.1.2 Input/Output Capacitors
      3. 12.1.3 Compensation Components
      4. 12.1.4 Traces and Ground Planes
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Trademarks
    2. 13.2 Electrostatic Discharge Caution
    3. 13.3 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

9.3.1 5-V Reference Regulator

The TL494 internal 5-V reference regulator output is the REF pin. In addition to providing a stable reference, it acts as a preregulator and establishes a stable supply from which the output-control logic, pulse-steering flip-flop, oscillator, dead-time control comparator, and PWM comparator are powered. The regulator employs a band-gap circuit as its primary reference to maintain thermal stability of less than 100-mV variation over the operating free-air temperature range of 0°C to 70°C. Short-circuit protection is provided to protect the internal reference and preregulator; 10 mA of load current is available for additional bias circuits. The reference is internally programmed to an initial accuracy of ±5% and maintains a stability of less than 25-mV variation over an input voltage range of 7 V to 40 V. For input voltages less than 7 V, the regulator saturates within 1 V of the input and tracks it.