SLVS074J January   1983  – September 2026 TL494

PRODUCTION DATA  

  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, Reference Section
    6. 5.6  Electrical Characteristics, Oscillator Section
    7. 5.7  Electrical Characteristics, Error-Amplifier Section
    8. 5.8  Electrical Characteristics, Output Section
    9. 5.9  Electrical Characteristics, Dead-Time Control Section
    10. 5.10 Electrical Characteristics, PWM Comparator Section
    11. 5.11 Electrical Characteristics, Total Device
    12. 5.12 Switching Characteristics
    13. 5.13 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 5V Reference Regulator
      2. 7.3.2 Oscillator
      3. 7.3.3 Dead-time Control
      4. 7.3.4 Comparator
      5. 7.3.5 Pulse-Width Modulation (PWM)
      6. 7.3.6 Error Amplifiers
      7. 7.3.7 Output-Control Input
      8. 7.3.8 Output Transistors
    4. 7.4 Device Functional Modes
  9. 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 Power Source
        2. 8.2.2.2 Control Circuits
          1. 8.2.2.2.1 Oscillator
          2. 8.2.2.2.2 Error Amplifier
          3. 8.2.2.2.3 Current-Limiting Amplifier
          4. 8.2.2.2.4 Soft Start and Dead Time
        3. 8.2.2.3 Inductor Calculations
        4. 8.2.2.4 Output Capacitance Calculations
        5. 8.2.2.5 Transistor Power-Switch Calculations
      3. 8.2.3 Application Curves for Output Characteristics
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
        1. 8.4.1.1 Feedback Traces
        2. 8.4.1.2 Input/Output Capacitors
        3. 8.4.1.3 Compensation Components
        4. 8.4.1.4 Traces and Ground Planes
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Documentation Support
      1. 9.3.1 Related Documentation
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

7.1 Overview

The design of the TL494 incorporates the primary building blocks required to control a switching power supply and addresses basic problems and reduces the amount of additional circuitry required in the total design. The TL494 is a fixed-frequency pulse-width-modulation (PWM) control circuit. The internal oscillator on the timing capacitor (CT) creates the sawtooth waveform. Achieve modulation of output pulses by comparing the sawtooth waveform to either of two control signals. The output stage is enabled during the time when the sawtooth voltage is greater than the voltage control signals. As the control signal increases, the time during which the sawtooth input is greater decreases; therefore, the output pulse duration decreases. A pulse-steering flip-flop alternately directs the modulated pulse to each of the two output transistors. For more information on the operation of the TL494, see the application notes located on ti.com.