SLVS038J January   1989  – October 2024 TL2842 , TL2843 , TL2844 , TL2845 , TL3842 , TL3843 , TL3844 , TL3845

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
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Pulse-by-Pulse Current Limiting
      2. 6.3.2 Error Amplifier With Low Output Resistance
      3. 6.3.3 High-Current Totem-Pole Output
    4. 6.4 Device Functional Modes
      1. 6.4.1 Shutdown Technique
      2. 6.4.2 Slope Compensation
  8. 7 Application and Implementation
    1. 7.1 Typical Application
      1. 7.1.1 Design Requirements
      2. 7.1.2 Detailed Design Procedure
        1. 7.1.2.1 Current-Sense Circuit
        2. 7.1.2.2 Error-Amplifier Configuration
        3. 7.1.2.3 Oscillator Section
      3. 7.1.3 Application Curve
    2. 7.2 Power Supply Recommendations
    3. 7.3 Layout
      1. 7.3.1 Layout Guidelines
        1. 7.3.1.1 Feedback Traces
        2. 7.3.1.2 Input/Output Capacitors
        3. 7.3.1.3 Compensation Components
        4. 7.3.1.4 Traces and Ground Planes
      2. 7.3.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • D|14
  • D|8
  • P|8
Thermal pad, mechanical data (Package|Pins)
Orderable Information

6.1 Overview

The TL284x and TL384x series of control integrated circuits provide the features that are necessary to implement off-line or DC-to-DC fixed-frequency current-mode control schemes, with a minimum number of external components. Some of the internally implemented circuits are an undervoltage lockout (UVLO), featuring a start-up current of less than 1 mA, and a precision reference trimmed for accuracy at the error amplifier input. Other internal circuits include logic to ensure latched operation, a pulse-width modulation (PWM) comparator (that also provides current-limit control), and a totem-pole output stage designed to source or sink high-peak current. The output stage, suitable for driving N-channel MOSFETs, is low when it is in the off state.

Major differences between members of these series are the UVLO thresholds and maximum duty-cycle ranges. Typical UVLO thresholds of 16 V (on) and 10 V (off) on the TLx842 and TLx844 devices make them ideally suited to off-line applications. The corresponding typical thresholds for the TLx843 and TLx845 devices are 8.4 V (on) and 7.6 V (off). The TLx842 and TLx843 devices can operate to duty cycles approaching 100%. A duty-cycle range of 0 to 50% is obtained by the TLx844 and TLx845 by the addition of an internal toggle flip-flop, which blanks the output off every other clock cycle.

The TL284x-series devices are characterized for operation from −40°C to +85°C. The TL384x devices are characterized for operation from 0°C to 70°C.