SNVSA82C April   2015  – October 2017 LM43603-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
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 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  Fixed Frequency Peak Current Mode Controlled Step-Down Regulator
      2. 7.3.2  Light Load Operation
      3. 7.3.3  Adjustable Output Voltage
      4. 7.3.4  Enable (EN)
      5. 7.3.5  VCC, UVLO, and BIAS
      6. 7.3.6  Soft-Start and Voltage Tracking (SS/TRK)
      7. 7.3.7  Switching Frequency (RT) and Synchronization (SYNC)
      8. 7.3.8  Minimum ON Time, Minimum OFF Time and Frequency Foldback at Dropout Conditions
      9. 7.3.9  Internal Compensation and CFF
      10. 7.3.10 Bootstrap Voltage (BOOT)
      11. 7.3.11 Power Good (PGOOD)
      12. 7.3.12 Overcurrent and Short-Circuit Protection
      13. 7.3.13 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Stand-by Mode
      3. 7.4.3 Active Mode
      4. 7.4.4 CCM Mode
      5. 7.4.5 Light Load Operation
      6. 7.4.6 Self-Bias Mode
  8. 8 Applications and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1  Custom Design With WEBENCH® Tools
        2. 8.2.2.2  Output Voltage Setpoint
        3. 8.2.2.3  Switching Frequency
        4. 8.2.2.4  Input Capacitors
        5. 8.2.2.5  Inductor Selection
        6. 8.2.2.6  Output Capacitor Selection
        7. 8.2.2.7  Feed-Forward Capacitor
        8. 8.2.2.8  Bootstrap Capacitors
        9. 8.2.2.9  VCC Capacitor
        10. 8.2.2.10 BIAS Capacitors
        11. 8.2.2.11 Soft-Start Capacitors
        12. 8.2.2.12 Undervoltage Lockout Setpoint
        13. 8.2.2.13 PGOOD
      3. 8.2.3 Application Performance Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Compact Layout for EMI Reduction
      2. 10.1.2 Ground Plane and Thermal Considerations
      3. 10.1.3 Feedback Resistors
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Development Support
      1. 11.2.1 Custom Design With WEBENCH® Tools
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

1 Features

  • Qualified for Automotive Applications
  • AEC-Q100 Qualified With the Following Results:
    • Device Temperature Grade 1: –40°C to +125°C Operating Junction Temperature
  • 27-µA Quiescent Current in Regulation
  • High Efficiency at Light Load (DCM and PFM)
  • Meets EN55022/CISPR 22 EMI Standards
  • Integrated Synchronous Rectification
  • Adjustable Frequency Range: 200 kHz to 2.2 MHz (500 kHz default)
  • Frequency Synchronization to External Clock
  • Internal Compensation
  • Stable With Almost any Combination of Ceramic, Polymer, Tantalum, and Aluminum Capacitors
  • Power-Good Flag
  • Soft Start into a Pre-Biased Load
  • Internal Soft Start: 4.1 ms
  • Extendable Soft-Start Time by External Capacitor
  • Output Voltage Tracking Capability
  • Precision Enable to a Program System UVLO
  • Output Short Circuit Protection with Hiccup Mode
  • Overtemperature Thermal Shutdown Protection
  • Create a Custom Design Using the LM43603-Q1 With the WEBENCH® Power Designer

2 Applications

  • Sub-AM Band Automotive
  • Industrial Power Supplies
  • General Purpose Wide VIN Regulation
  • High Efficiency Point-Of-Load Regulation
  • Telecommunications Systems

3 Description

The LM43603-Q1 regulator is an easy-to-use synchronous step-down DC-DC converter capable of driving up to 3 A of load current from an input voltage ranging from 3.5 V to 36 V (42 V absolute maximum). The LM43603-Q1 provides exceptional efficiency, output accuracy, and dropout voltage in a very small solution size. An extended family is available in 0.5-A, 1-A, and 2-A load current options in pin-to-pin compatible packages. Peak current mode control is employed to achieve simple control loop compensation and cycle-by-cycle current limiting. Optional features such as programmable switching frequency, synchronization, power-good flag, precision enable, internal soft-start, extendable soft start, and tracking provide a flexible and easy to use platform for a wide range of applications. Discontinuous conduction and automatic frequency modulation at light loads improve light load efficiency. The family requires few external components and pin arrangement allows simple, optimum PCB layout. Protection features include thermal shutdown, VCC undervoltage lockout, cycle-by-cycle current limit, and output short circuit protection. The LM43603-Q1 device is available in the HTSSOP (PWP) 16-pin leaded package (6.6 mm × 5.1 mm × 1.2 mm). The LM43603A-Q1 version is optimized for PFM operation and recommended for new design. The device is pin-to-pin compatible with LM4360x and LM4600x family.

Device Information

PART NUMBER PACKAGE BODY SIZE
LM43603-Q1 HTSSOP (16) 6.60 mm × 5.10 mm
LM43603A-Q1 HTTSOP (16) 6.60 mm × 5.10 mm


Simplified Schematic

LM43603-Q1 sch_basic01_LM43603Q.png

Radiated Emission Graph
12 VIN to 3.3 VOUT, FS = 500 kHz, IOUT = 3 A

LM43603-Q1 Rad_12VIN3p3V500k3AGr.png