SNVS731B September   2011  – June 2019 LMR12010

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Descriptions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 Recommended Operating Ratings
    3. 6.3 Electrical Characteristics
    4. 6.4 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 Boost Function
      2. 7.3.2 Enable Pin / Shutdown Mode
      3. 7.3.3 Soft Start
      4. 7.3.4 Output Overvoltage Protection
      5. 7.3.5 Undervoltage Lockout
      6. 7.3.6 Current Limit
      7. 7.3.7 Thermal Shutdown
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1.      Typical Application
      2. 8.2.1 Detailed Design Procedure
        1. 8.2.1.1 Custom Design With WEBENCH® Tools
        2. 8.2.1.2 Inductor Selection
        3. 8.2.1.3 Input Capacitor
        4. 8.2.1.4 Output Capacitor
        5. 8.2.1.5 Catch Diode
        6. 8.2.1.6 Boost Diode
        7. 8.2.1.7 Boost Capacitor
        8. 8.2.1.8 Output Voltage
        9. 8.2.1.9 Calculating Efficiency, and Junction Temperature
      3. 8.2.2 Application Curves
  9. 9 Layout
    1. 9.1 Layout Considerations
    2. 9.2 Calculating The LMR12010 Junction Temperature
  10. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
      2. 10.1.2 Development Support
        1. 10.1.2.1 Custom Design With WEBENCH® Tools
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Community Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DDC|6
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.1 Overview

The LMR12010 is a constant frequency PWM buck regulator IC that delivers a 1-A load current. The regulator has a preset switching frequency of either 3 MHz (LMR12010Y) or 1.6 MHz (LMR12010X). These high frequencies allow the LMR12010 to operate with small surface mount capacitors and inductors, resulting in DC/DC converters that require a minimum amount of board space. The LMR12010 is internally compensated, so it is simple to use, and requires few external components. The LMR12010 uses current-mode control to regulate the output voltage.

The following operating description of the LMR12010 refers to the functional block diagram (Functional Block Diagram) and to the waveforms in Figure 14. The LMR12010 supplies a regulated output voltage by switching the internal NMOS control switch at constant frequency and variable duty cycle. A switching cycle begins at the falling edge of the reset pulse generated by the internal oscillator. When this pulse goes low, the output control logic turns on the internal NMOS control switch. During this on-time, the SW pin voltage (VSW) swings up to approximately VIN, and the inductor current (IL) increases with a linear slope. IL is measured by the current-sense amplifier, which generates an output proportional to the switch current. The sense signal is summed with the regulator’s corrective ramp and compared to the error amplifier’s output, which is proportional to the difference between the feedback voltage and VREF. When the PWM comparator output goes high, the output switch turns off until the next switching cycle begins. During the switch off-time, inductor current discharges through Schottky diode D1, which forces the SW pin to swing below ground by the forward voltage (VD) of the catch diode. The regulator loop adjusts the duty cycle (D) to maintain a constant output voltage.

LMR12010 30166507.gifFigure 14. LMR12010 Waveforms Of SW Pin Voltage and Inductor Current