SNVS556C April   2008  – January 2016 LM2738

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 Boost Function
      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
      1. 7.4.1 Enable Pin and Shutdown Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1  LM2738X Circuit 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
          6. 8.2.1.2.6 Calculating Efficiency and Junction Temperature
        3. 8.2.1.3 Application Curve
      2. 8.2.2  LM2738X Circuit Example 2
        1. 8.2.2.1 Detailed Design Procedure
        2. 8.2.2.2 Application Curve
      3. 8.2.3  LM2738X Circuit Example 3
        1. 8.2.3.1 Detailed Design Procedure
        2. 8.2.3.2 Application Curve
      4. 8.2.4  LM2738X Circuit Example 4
        1. 8.2.4.1 Detailed Design Procedure
      5. 8.2.5  LM2738X Circuit Example 5
        1. 8.2.5.1 Detailed Design Procedure
      6. 8.2.6  LM2738Y Circuit Example 6
        1. 8.2.6.1 Detailed Design Procedure
        2. 8.2.6.2 Application Curve
      7. 8.2.7  LM2738Y Circuit Example 7
        1. 8.2.7.1 Detailed Design Procedure
        2. 8.2.7.2 Application Curve
      8. 8.2.8  LM2738Y Circuit Example 8
        1. 8.2.8.1 Detailed Design Procedure
        2. 8.2.8.2 Application Curve
      9. 8.2.9  LM2738Y Circuit Example 9
        1. 8.2.9.1 Detailed Design Procedure
        2. 8.2.9.2 Application Curve
      10. 8.2.10 LM2738Y Circuit Example 10
        1. 8.2.10.1 Detailed Design Procedure
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 WSON Package
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
      1. 10.3.1 Silicon Junction Temperature Determination Methods
        1. 10.3.1.1 Method 1
        2. 10.3.1.2 Method 2
  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, VCC –0.5 24 V
SW voltage –0.5 24 V
Boost voltage –0.5 30 V
Boost to SW voltage –0.5 6 V
FB voltage –0.5 3 V
EN voltage –0.5 VIN + 0.3 V
Junction temperature 150 °C
Soldering information Infrared and convection reflow (15 s) 220 °C
Wave soldering lead temperature (10 s) 260 °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 or Aerospace specified devices are required, contact the Texas Instruments Sales Office or Distributors for availability and specifications.

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)(2) ±2000 V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) Human body model, 1.5 kΩ in series with 100 pF.

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN MAX UNIT
VIN, VCC 3 20 V
SW voltage –0.5 20 V
Boost voltage –0.5 25.5 V
Boost to SW voltage 2.5 5.5 V
Junction temperature −40 125 °C
Thermal shutdown 165 °C

6.4 Thermal Information

THERMAL METRIC(1) LM2738 UNIT
NGQ (WSON) DGN (MSOP PowerPAD)
8 PINS 8 PINS
RθJA Junction-to-ambient thermal resistance (2) 45.9 50.3 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 44.6 54.2 °C/W
RθJB Junction-to-board thermal resistance 13.2 31.4 °C/W
ψJT Junction-to-top characterization parameter 0.5 4.8 °C/W
ψJB Junction-to-board characterization parameter 13.2 31.2 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance 5.8 4 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and device Package Thermal Metrics application report, SPRA953.
(2) Typical thermal shutdown occurs if the junction temperature exceeds 165°C. The maximum power dissipation is a function of TJ(MAX) , RθJA and TA . The maximum allowable power dissipation at any ambient temperature is PD = (TJ(MAX) – TA) / RθJA. All numbers apply for packages soldered directly onto a 3 inches × 3 inches PC board with 2 oz. copper on 4 layers in still air in accordance to JEDEC standards. Thermal resistance varies greatly with layout, copper thickness, number of layers in PCB, power distribution, number of thermal vias, board size, ambient temperature, and air flow.

6.5 Electrical Characteristics

All typical limits apply over TJ = 25°C, and all maximum and minimum limits apply over the full operating temperature range (TJ = –40°C to +125°C). VIN = 12 V, VBOOST – VSW = 5 V unless otherwise specified. Data sheet minimum and maximum specification limits are ensured by design, test, or statistical analysis.
PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX(1) UNIT
VFB Feedback voltage 0.784 0.800 0.816 V
ΔVFB/ΔVIN Feedback voltage line regulation VIN = 3 V to 20 V 0.02 %/V
IFB Feedback input bias current Sink or source 0.1 100 nA
UVLO Undervoltage lockout VIN Rising 2.7 2.9 V
Undervoltage lockout VIN Falling 2 2.3
UVLO hysteresis 0.4
FSW Switching frequency LM2738X 1.28 1.6 1.92 MHz
LM2738Y 0.364 0.55 0.676
DMAX Maximum duty cycle LM2738X , Load = 150 mA 92%
LM2738Y, Load = 150 mA 95%
DMIN Minimum duty cycle LM2738X 7.5%
LM2738Y 2%
RDS(ON) Switch ON resistance VBOOST – VSW = 3 V, Load = 400 mA 250 500 mΩ
ICL Switch current limit VBOOST – VSW = 3 V, VIN = 3 V 2 2.9 A
IQ Quiescent current Switching 1.9 3 mA
Non-Switching 1.9 mA
Quiescent current (shutdown) VEN = 0 V 400 nA
IBOOST Boost pin current LM2738X (27% Duty Cycle) 4.5 mA
LM2738Y (27% Duty Cycle) 2.5
VEN_TH Shutdown threshold voltage VEN Falling 0.4 V
Enable threshold voltage VEN Rising 1.4
IEN Enable pin current Sink / Source 10 nA
ISW Switch leakage VIN = 20 V 100 nA
(1) Ensured to average outgoing quality level (AOQL).
(2) Typicals represent the most likely parametric norm.

6.6 Typical Characteristics

All curves taken at VIN = 12 V, VBOOST – VSW = 5 V, and TA = 25°C, unless specified otherwise.
LM2738 30049197.png
VOUT = 5 V
Figure 1. Efficiency vs Load Current – X Version
LM2738 30049151.png
VOUT = 3.3 V
Figure 3. Efficiency vs Load Current – X Version
LM2738 30049199.png
VOUT = 1.5 V
Figure 5. Efficiency vs Load Current – X Version
LM2738 30049127.png Figure 7. Oscillator Frequency vs Temperature – X Version
LM2738 30049129.png
VIN = 5 V
Figure 9. Current Limit vs Temperature
LM2738 30049133.png Figure 11. VFB vs Temperature
LM2738 30049156.png
VOUT = 1.5 V IOUT = 750 mA
Figure 13. Line Regulation – X Version
LM2738 30049155.png
VOUT = 3.3 V IOUT = 750 mA
Figure 15. Line Regulation – X Version
LM2738 30049176.png
VOUT = 1.5 V
Figure 17. Load Regulation – X Version
LM2738 30049177.png
VOUT = 3.3 V
Figure 19. Load Regulation – X Version
LM2738 30049146.png Figure 21. IQ Switching vs Temperature
LM2738 30049190.png
VOUT = 3.3 V VIN = 12 V IOUT = 1.5 A
Figure 23. Startup – X Version (Resistive Load)
LM2738 30049198.png
VOUT = 5 V
Figure 2. Efficiency vs Load Current – Y Version
LM2738 30049152.png
VOUT = 3.3 V
Figure 4. Efficiency vs Load Current – Y Version
LM2738 30049131.png
VOUT = 1.5 V
Figure 6. Efficiency vs Load Current – Y Version
LM2738 30049128.png Figure 8. Oscillator Frequency vs Temperature – Y Version
LM2738 30049147.png
Figure 10. IQ Non-Switching vs Temperature
LM2738 30049130.png Figure 12. RDSON vs Temperature
LM2738 30049154.png
VOUT = 1.5 V IOUT = 750 mA
Figure 14. Line Regulation – Y Version
LM2738 30049153.png
VOUT = 3.3 V IOUT = 750 mA
Figure 16. Line Regulation – Y Version
LM2738 30049175.png
VOUT = 1.5 V
Figure 18. Load Regulation – Y Version
LM2738 30049178.png
VOUT = 3.3 V
Figure 20. Load Regulation – Y Version
LM2738 30049194.png
VOUT = 3.3 V VIN = 12 V
Figure 22. Load Transient – X Version
LM2738 30049191.png
VOUT = 3.3 V VIN = 12 V IOUT = 1.5 A
Figure 24. In-Rush Current – X Version (Resistive Load)