SNVS422D August   2006  – September 2015 LM2831

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 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 Theory of Operation
      2. 7.3.2 Soft Start
      3. 7.3.3 Output Overvoltage Protection
      4. 7.3.4 Undervoltage Lockout
      5. 7.3.5 Current Limit
      6. 7.3.6 Thermal Shutdown
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 LM2831X Design Example 1
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Inductor Selection
          2. 8.2.1.2.2 Input Capacitor
          3. 8.2.1.2.3 Output Capacitor
          4. 8.2.1.2.4 Catch Diode
          5. 8.2.1.2.5 Output Voltage
        3. 8.2.1.3 Application Curves
      2. 8.2.2 LM2831X Design Example 2
      3. 8.2.3 LM2831X Design Example 3
      4. 8.2.4 LM2831Y Design Example 4
      5. 8.2.5 LM2831Y Design Example 5
      6. 8.2.6 LM2831Z Design Example 6
      7. 8.2.7 LM2831Z Design Example 7
      8. 8.2.8 LM2831X Dual Converters with Delayed Enabled Design Example 8
      9. 8.2.9 LM2831X Buck Converter and Voltage Double Circuit With LDO Follower Design Example 9
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Calculating Efficiency and Junction Temperature
      2. 10.1.2 Thermal Definitions
        1. 10.1.2.1 Silicon Junction Temperature Determination Method 1
      3. 10.1.3 WSON Package
    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 Documentation Support
      1. 11.2.1 Related Documentation
    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

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)(2)
MIN MAX UNIT
VIN –0.5 7 V
FB Voltage –0.5 3 V
EN Voltage –0.5 7 V
SW Voltage –0.5 7 V
Junction Temperature(3) 150 °C
Soldering Information   Infrared or Convection Reflow (15 sec) 220 °C
Storage Temperature, Tstg –65 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and specifications.
(3) Thermal shutdown will occur if the junction temperature exceeds the maximum junction temperature of the device.

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNIT
VIN 3 5.5 V
Junction Temperature –40 125 °C

6.4 Thermal Information

THERMAL METRIC(1) LM2831 UNIT
SOT-23 (DBV WSON (NGG)
5 PINS 6 PINS
RθJA Junction-to-ambient thermal resistance(2) 163.4 54.9 °C/W
RθJC(top) Junction-to-case (top) thermal resistance(2) 114.4 50.8 °C/W
RθJB Junction-to-board thermal resistance 26.8 29.2 °C/W
ψJT Junction-to-top characterization parameter 12.4 0.6 °C/W
ψJB Junction-to-board characterization parameter 26.2 29.3 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance N/A 9.2 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953.
(2) Applies for packages soldered directly onto a 3” × 3” PC board with 2 oz. copper on 4 layers in still air.

6.5 Electrical Characteristics

VIN = 5 V unless otherwise indicated under the Test Conditions column. Limits are for TJ = 25°C. Minimum and Maximum limits are specified through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
VFB Feedback Voltage WSON and SOT-23 Package TJ = 25°C 0.600 V
–40°C to 125°C 0.588 0.612
ΔVFB/VIN Feedback Voltage Line Regulation VIN = 3 V to 5 V 0.02 %/V
IB Feedback Input Bias Current TJ = 25°C 0.1 nA
–40°C to 125°C 100
UVLO Undervoltage Lockout VIN Rising TJ = 25°C 2.73 V
–40°C to 125°C 2.90
VIN Falling TJ = 25°C 2.3 V
–40°C to 125°C 1.85
UVLO Hysteresis 0.43 V
FSW Switching Frequency LM2831-X TJ = 25°C 1.6 MHz
–40°C to 125°C 1.2 1.95
LM2831-Y TJ = 25°C 0.55
–40°C to 125°C 0.4 0.7
LM2831-Z TJ = 25°C 3
–40°C to 125°C 2.25 3.75
DMAX Maximum Duty Cycle LM2831-X TJ = 25°C 94%
–40°C to 125°C 86%
LM2831-Y TJ = 25°C 96%
–40°C to 125°C 90%
LM2831-Z TJ = 25°C 90%
–40°C to 125°C 82%
DMIN Minimum Duty Cycle LM2831-X 5%
LM2831-Y 2%
LM2831-Z 7%
RDS(ON) Switch On Resistance WSON Package 150 mΩ
SOT-23 Package TJ = 25°C 130
–40°C to 125°C 195
ICL Switch Current Limit VIN = 3.3 V TJ = 25°C 2.5 A
–40°C to 125°C 1.8
VEN_TH Shutdown Threshold Voltage –40°C to 125°C 0.4 V
Enable Threshold Voltage –40°C to 125°C 1.8
ISW Switch Leakage 100 nA
IEN Enable Pin Current Sink/Source 100 nA
IQ Quiescent Current (switching) LM2831X VFB = 0.55 TJ = 25°C 3.3 mA
–40°C to 125°C 5
LM2831Y VFB = 0.55 TJ = 25°C 2.8
–40°C to 125°C 4.5
LM2831Z VFB = 0.55 TJ = 25°C 4.3
–40°C to 125°C 6.5
Quiescent Current (shutdown) All Options VEN = 0 V 30 nA
TSD Thermal Shutdown Temperature 165 °C

6.6 Typical Characteristics

All curves taken at VIN = 5 V with configuration in typical application circuit shown in Application Information section of this datasheet. TJ = 25°C, unless otherwise specified.
LM2831 20174885.png
VIN = 3.3 VO = 1.8 V
Figure 1. η vs Load – X, Y, and Z Options
LM2831 20174845.gif
VIN = 5 V VO = 1.8 V (All Options)
Figure 3. Load Regulation
LM2831 20174824.gif Figure 5. Oscillator Frequency vs Temperature – X Option
LM2831 20174836.gif
Figure 7. Oscillator Frequency vs Temperature – Z Option
LM2831 20174883.png Figure 9. RDSON vs Temperature (WSON Package)
LM2831 20174828.gif Figure 11. LM2831X IQ (Quiescent Current)
LM2831 20174837.gif
Figure 13. LM2831Z IQ (Quiescent Current)
LM2831 20174827.gif
Figure 15. VFB vs Temperature
LM2831 20174857.png
VIN = 5 V VO = 1.2 V at 1 A
Figure 17. Phase Plot vs Frequency
LM2831 20174844.gif
VIN = 3.3 V VO = 1.8 V (All Options)
Figure 2. Load Regulation
LM2831 20174846.gif
VIN = 5 V VO = 3.3 V (All Options)
Figure 4. Load Regulation
LM2831 20174825.gif Figure 6. Oscillator Frequency vs Temperature – Y Option
LM2831 20174823.gif
VIN = 3.3 V
Figure 8. Current Limit vs Temperature
LM2831 20174884.png Figure 10. RDSON vs Temperature (SOT-23 Package)
LM2831 20174829.gif Figure 12. LM2831Y IQ (Quiescent Current)
LM2831 20174853.png
VO = 1.8 V IO = 500 mA
Figure 14. Line Regulation
LM2831 20174856.png
VIN = 5 V VO = 1.2 V at 1 A
Figure 16. Gain vs Frequency