SNVS443C May   2006  – December 2016 LM3489 , LM3489-Q1

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: LM3489
    3. 6.3 ESD Ratings: LM3489-Q1
    4. 6.4 Recommended Operating Conditions
    5. 6.5 Thermal Information
    6. 6.6 Electrical 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 Hysteretic Control Circuit
        1. 7.3.1.1 Delay
      2. 7.3.2 Current Limit Operation
      3. 7.3.3 Start Up
      4. 7.3.4 External Sense Resistor
      5. 7.3.5 PGATE
      6. 7.3.6 Adjustable UVLO
    4. 7.4 Device Functional Mode
      1. 7.4.1 Device Enable and Shutdown
  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 Inductor Selection (L)
        2. 8.2.2.2 Output Capacitor Selection (COUT)
        3. 8.2.2.3 Input Capacitor Selection (CIN)
        4. 8.2.2.4 Programming the Current Limit (RADJ)
        5. 8.2.2.5 Catch Diode Selection (D1)
        6. 8.2.2.6 P-Channel MOSFET Selection (Q1)
        7. 8.2.2.7 Interfacing With the Enable Pin
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Related Links
    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

  • Qualified for Automotive Parts
  • AEC-Q100 Qualified With the Following Results:
    • Device Temperature Grade 1: –40°C to 125°C Ambient Operating Temperature Range
    • Device HBM ESD Classification Level 2
    • Device CDM ESD Classification Level C5
  • Easy-to-Use Control Methodology
  • No Control Loop Compensation Required
  • Wide 4.5-V to 35-V Input Range
  • 1.239 V to VIN Adjustable Output Range
  • High Efficiency: 93%
  • ±1.3% (±2% Over Temperature) Internal Reference
  • 100% Duty Cycle Operation
  • Maximum Operation Frequency > 1 MHz
  • Current Limit Protection
  • Dedicated Enable Pin (on if Unconnected)
  • Shutdown Mode Draws Only 7-µA Supply Current
  • 8-Pin VSSOP Package

2 Applications

  • Set-Top Boxes
  • DSL or Cable Modems
  • PC/IA
  • Auto PCs
  • TFT Monitors
  • Battery-Powered Portable Applications
  • Distributed Power Systems
  • Always-On Power
  • High-Power LED Drivers
  • Automotive

3 Description

The LM3489 device is a high-efficiency PFET switching regulator controller that can be used to quickly and easily develop a small, cost-effective, switching buck regulator for a wide range of applications. The hysteretic control architecture provides for simple design without any control loop stability concerns using a wide variety of external components. The PFET architecture also allows for low component count as well as ultra-low dropout, 100% duty cycle operation. Another benefit is high efficiency operation at light loads without an increase in output ripple. A dedicated enable pin provides a shutdown mode drawing only 7 µA. Leaving the enable pin unconnected defaults to on.

Current limit protection can be implemented by measuring the voltage across the PFET’s RDS(ON), thus eliminating the need for a sense resistor. A sense resistor may be used to improve current limit accuracy if desired. The cycle-by-cycle current limit can be adjusted with a single resistor, ensuring safe operation over a range of output currents.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LM3489
LM3489-Q1		 VSSOP (8) 3.00 mm × 3.00 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application Circuit

LM3489 LM3489-Q1 20186908.gif