SNVS608H June   2009  – September 2016 LM5009A

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 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Control Circuit Overview
      2. 7.3.2 Start-Up Regulator (VCC)
      3. 7.3.3 Regulation Comparator
      4. 7.3.4 Overvoltage Comparator
      5. 7.3.5 ON-Time Generator and Shutdown
      6. 7.3.6 Current Limit
      7. 7.3.7 N-Channel Buck Switch and Driver
      8. 7.3.8 Thermal Protection
    4. 7.4 Device Functional Modes
  8. 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  RFB1 and RFB2
        2. 8.2.2.2  Fs and RT
        3. 8.2.2.3  L1
          1. 8.2.2.3.1 Minimum Load Current
          2. 8.2.2.3.2 Maximum Load Current
        4. 8.2.2.4  C3
        5. 8.2.2.5  C2 and R3
        6. 8.2.2.6  ESR and R3
        7. 8.2.2.7  C2
        8. 8.2.2.8  RCL
        9. 8.2.2.9  D1
        10. 8.2.2.10 C1
        11. 8.2.2.11 C4
        12. 8.2.2.12 C5
        13. 8.2.2.13 Ripple Configuration
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

1 Features

  • Operating Input Voltage Range: 6 V to 95 V
  • Integrated 100-V, N-Channel Buck Switch
  • Internal Start-Up Regulator
  • No Loop Compensation Required
  • Ultra-Fast Transient Response
  • ON Time Varies Inversely With Input Voltage
  • Operating Frequency Remains Constant With Varying Line Voltage and Load Current
  • Adjustable Output Voltage From 2.5 V
  • Highly Efficient Operation
  • Precision Internal Reference
  • Low Bias Current
  • Intelligent Current Limit
  • Thermal Shutdown
  • 8-Pin VSSOP and 8-Pin WSON (4 mm × 4 mm) Packages

2 Applications

  • Non-Isolated Telecommunication Buck Regulator
  • Secondary High-Voltage Post Regulator
  • 42-V Automotive Systems

3 Description

The LM5009A is a functional variant of the LM5009 COT buck switching regulator. The functional differences of the LM5009A are: The minimum input operating voltage is 6 V, the ON-time equation is slightly different, and the requirement for a minimum load current is removed.

The LM5009A step-down switching regulator features all of the functions required to implement a low cost, efficient, buck bias regulator. This high voltage regulator contains an 100-V N-channel buck switch. The device is easy to implement and is provided in the 8-pin VSSOP and the thermally enhanced 8-pin WSON packages. The regulator is based on a control scheme using an ON time inversely proportional to VIN. This feature allows the operating frequency to remain relatively constant. The control scheme requires no loop compensation. An intelligent current limit is implemented with forced OFF time, which is inversely proportional to VOUT. This scheme ensures short-circuit control while providing minimum foldback. Other features include: thermal shutdown, undervoltage lockout (VCC), gate drive undervoltage lockout, max duty cycle limiter, and a precharge switch.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LM5009A VSSOP (8) 4.00 mm × 4.00 mm
WSON (8) 4.00 mm × 4.00 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application, Basic Step-Down Regulator

LM5009A 30087101.gif