SNVS497F November   2008  – September 2016 LM27341 , LM27341-Q1 , LM27342 , LM27342-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 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 Low Input Voltage Considerations
      3. 7.3.3 High Output Voltage Considerations
      4. 7.3.4 Frequency Synchronization
      5. 7.3.5 Current Limit
      6. 7.3.6 Frequency Foldback
      7. 7.3.7 Output Overvoltage Protection
      8. 7.3.8 Undervoltage Lockout
      9. 7.3.9 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Enable Pin and Shutdown Mode
      2. 7.4.2 Soft-Start Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1  Inductor Selection
        1. 8.1.1.1 Inductor Calculation Example
      2. 8.1.2  Inductor Material Selection
      3. 8.1.3  Input Capacitor
      4. 8.1.4  Output Capacitor
      5. 8.1.5  Catch Diode
      6. 8.1.6  Boost Diode (Optional)
      7. 8.1.7  Boost Capacitor
      8. 8.1.8  Output Voltage
      9. 8.1.9  Feedforward Capacitor (Optional)
      10. 8.1.10 Calculating Efficiency and Junction Temperature
        1. 8.1.10.1 Schottky Diode Conduction Losses
        2. 8.1.10.2 Inductor Conduction Losses
        3. 8.1.10.3 MOSFET Conduction Losses
        4. 8.1.10.4 MOSFET Switching Losses
        5. 8.1.10.5 IC Quiescent Losses
        6. 8.1.10.6 MOSFET Driver Losses
        7. 8.1.10.7 Total Power Losses
        8. 8.1.10.8 Efficiency Calculation Example
        9. 8.1.10.9 Calculating Junction Temperature
          1. 8.1.10.9.1 Conduction
          2. 8.1.10.9.2 Convection
          3. 8.1.10.9.3 Method 1
          4. 8.1.10.9.4 Method 2
            1. 8.1.10.9.4.1 Method 2 Example
          5. 8.1.10.9.5 Method 3
            1. 8.1.10.9.5.1 Method 3 Example
    2. 8.2 Typical Applications
      1. 8.2.1 LM2734x Configuration From VIN = 7 V to 16 V, VOUT = 5 V For Full Load at 2 MHz
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 LM2734x Configuration From VIN = 7 V to 16 V, VOUT = 5 V For Full Load at 1 MHz
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
      3. 8.2.3 LM2734x Configuration From VIN = 5 V to 16 V, VOUT = 3.3 V For Full Load at 2 MHz
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
        3. 8.2.3.3 Application Curves
      4. 8.2.4 LM2734x Configuration From VIN = 5 V to 16 V, VOUT = 3.3 V For Full Load at 2 MHz With SYNC = GND
        1. 8.2.4.1 Design Requirements
        2. 8.2.4.2 Detailed Design Procedure
        3. 8.2.4.3 Application Curves
      5. 8.2.5 LM2734x Configuration From VIN = 5 V to 16 V, VOUT = 3.3 V For Full Load at 2 MHz With SYNC = 1 MHz
        1. 8.2.5.1 Design Requirements
        2. 8.2.5.2 Detailed Design Procedure
        3. 8.2.5.3 Application Curves
      6. 8.2.6 LM2734x Configuration From VIN = 3.3 V to 16 V, VOUT = 1.8 V For Full Load at 2 MHz With SYNC = 1 GND
        1. 8.2.6.1 Design Requirements
        2. 8.2.6.2 Detailed Design Procedure
        3. 8.2.6.3 Application Curves
      7. 8.2.7 LM2734x Configuration From VIN = 3.3 V to 16 V, VOUT = 1.8 V For Full Load at 2 MHz With SYNC = 1 MHz
        1. 8.2.7.1 Design Requirements
        2. 8.2.7.2 Detailed Design Procedure
        3. 8.2.7.3 Application Curves
      8. 8.2.8 LM2734x Configuration From VIN = 3.3 V to 9 V, VOUT = 1.2 V For Full Load at 2 MHz With SYNC = 2 MHz
        1. 8.2.8.1 Design Requirements
        2. 8.2.8.2 Detailed Design Procedure
        3. 8.2.8.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Compact Layout
      2. 10.1.2 Ground Plane and Shape Routing
      3. 10.1.3 FB Loop
      4. 10.1.4 PCB Summary
    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 Related Links
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Community Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 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
AVIN, PVIN –0.5 24 V
SW voltage –0.5 24 V
Boost voltage –0.5 28 V
Boost to SW voltage –0.5 6 V
FB voltage –0.5 3 V
SYNC voltage –0.5 6 V
EN voltage –0.5 VIN + 0.3 V
Soldering, infrared reflow (5 s) 260 °C
Junction temperature, TJ 150 °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.

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)(1)
MIN MAX UNIT
AVIN, PVIN 3 20 V
SW voltage –0.5 20 V
Boost voltage –0.5 24 V
Boost to SW voltage 3 5.5 V
Junction temperature –40 125 °C
(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur, including inoperability and degradation of device reliability and/or performance. Functional operation of the device and/or non-degradation at the Absolute Maximum Ratings or other conditions beyond those indicated in the recommended Operating Ratings is not implied. The recommended Operating Ratings indicate conditions at which the device is functional and should not be operated beyond such conditions.

6.4 Thermal Information

THERMAL METRIC(1) LM2734x, LM2734x-Q1 UNIT
DSC (WSON) DGQ (MSOP-PowerPAD)
10 PINS 10 PINS
RθJA Junction-to-ambient thermal resistance(2) 47.6 49.5 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 36.5 53.6 °C/W
RθJB Junction-to-board thermal resistance 22.5 33.7 °C/W
ψJT Junction-to-top characterization parameter 0.4 3.9 °C/W
ψJB Junction-to-board characterization parameter 22.7 33.4 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance 4.7 3.5 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.
(2) Thermal shutdown will occur 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" × 3" PCB with 2 oz. copper on 4 layers in still air.

6.5 Electrical Characteristics

TJ = 25°C, VIN = 12 V, and VBOOST – VSW = 4.3 V (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
SYSTEM PARAMETERS
VFB Feedback voltage TJ = 0°C to 85°C 0.99 1 1.01 V
TJ = –40°C to 125°C 0.984 1 1.014
ΔVFB/ΔVIN Feedback voltage line regulation VIN = 3 V to 20 V 0.003% V
IFB Feedback input bias current TJ = 25°C 20 nA
TJ = –40°C to 125°C 100
OVP Overvoltage protection VFB at which PWM halts 1.13 V
UVLO Undervoltage lockout VIN rising until VSW is switching TJ = 25°C 2.75 V
TJ = –40°C to 125°C 2.6 2.9
Undervoltage hysteresis VIN falling from UVLO TJ = 25°C 0.47
TJ = –40°C to 125°C 0.3 0.6
SS Soft-start time 0.5 1 1.5 ms
IQ Quiescent current IQ = IQ_AVIN + IQ_PVIN VFB = 1.1 (not switching) 2.4 mA
VEN = 0 V (shutdown) 70 nA
IBOOST Boost pin current fSW= 2 MHz TJ = 25°C 8.2 mA
TJ = –40°C to 125°C 10
fSW= 1 MHz 4.4 6
OSCILLATOR
fSW Switching frequency SYNC = GND TJ = 25°C 2 MHz
TJ = –40°C to 125°C 1.75 2.3
VFB_FOLD FB pin voltage SYNC input is overridden 0.53 V
fFOLD_MIN Frequency foldback minimum VFB = 0 V 220 250 kHz
LOGIC INPUTS (EN, SYNC)
fSYNC SYNC frequency range 1 2.35 MHz
VIL EN, SYNC logic low threshold Logic falling edge 0.4 V
VIH EN, SYNC logic high threshold Logic rising edge 1.8
tSYNC_HIGH SYNC, time required above VIH to ensure a logical high 100 ns
tSYNC_LOW SYNC, time required below VIL to ensure a logical low 100 ns
ISYNC SYNC pin current VSYNC < 5 V 20 nA
IEN Enable pin current VEN = 3 V 6 15 µA
VIN = VEN = 20 V 50 100
INTERNAL MOSFET
RDS(ON) Switch ON-resistance TJ = 25°C 150 mΩ
TJ = –40°C to 125°C 320
ICL Switch current limit TJ = –40°C to 125°C LM27342 2.5 4 A
LM27341 2 3.7
DMAX Maximum duty cycle SYNC = GND TJ = 25°C 93%
TJ = –40°C to 125°C 85%
tMIN Minimum ON-time 65 ns
ISW Switch leakage current 40 nA
BOOST LDO
VLDO Boost LDO output voltage 3.9 V
THERMAL
TSHDN Thermal shutdown temperature Junction temperature rising 165 °C
Thermal shutdown hysteresis Junction temperature falling 15

6.6 Typical Characteristics

TA = 25°C, VIN = 12 V, and VBOOST – VSW = 4.3 V (unless otherwise noted)
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005676.png
VOUT = 5 V fSW = 2 MHz
Figure 1. Efficiency vs Load Current
See Figure 34
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005680.png
VOUT = 3.3 V fSW = 2 MHz
Figure 3. Efficiency vs Load Current
See Figure 40
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005684.png
VOUT = 1.8 V fSW = 2 MHz
Figure 5. Efficiency vs Load Current
See Figure 49
LM27341 LM27342 LM27341-Q1 LM27342-Q1 300056109.png
VIN = 10 V to 15 V VOUT = 3.3 V No CFF
Figure 7. Line Transient
See Figure 43
LM27341 LM27342 LM27341-Q1 LM27342-Q1 300056110.png Figure 9. Short Circuit
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005653.png Figure 11. Soft Start With EN Tied to VIN
LM27341 LM27342 LM27341-Q1 LM27342-Q1 300056112.png
VIN = 12 V L = 2.2 µH Iout =1 A
VOUT = 5 V COUT = 44 µF
Figure 13. Bode Plot
See Figure 34
LM27341 LM27342 LM27341-Q1 LM27342-Q1 300056114.png
VIN = 5 V L = 1.0 µH Iout =1 A
VOUT = 1.8 V COUT = 44 µF
Figure 15. Bode Plot
See Figure 49
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005655.png Figure 17. Sync Functionality
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005628.png
VSYNC = GND fSW = 2 MHz
Figure 19. Oscillator Frequency vs Temperature
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005630.png Figure 21. VFB vs Temperature
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005632.png
VIN = 12 V
Figure 23. Current Limit vs Temperature
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005634.png
IQ = IAVIN + IPVIN
Figure 25. IQ (Shutdown) vs Temperature
LM27341 LM27342 LM27341-Q1 LM27342-Q1 300056100.png
VOUT = 5 V IOUT = 100 mA – 2 A at Slewrate = 2 A / µs
Figure 2. Load Transient
See Figure 34
LM27341 LM27342 LM27341-Q1 LM27342-Q1 300056102.png
VOUT = 3.3 V IOUT = 100 mA – 2 A at Slewrate = 2 A / µs
Figure 4. Load Transient
See Figure 40
LM27341 LM27342 LM27341-Q1 LM27342-Q1 300056105.png
VOUT = 1.8 V IOUT = 100 mA – 2 A at Slewrate = 2 A / µs
Figure 6. Load Transient
See Figure 49
LM27341 LM27342 LM27341-Q1 LM27342-Q1 300056108.png
VIN = 10 V to 15 V VOUT = 3.3 V
Figure 8. Line Transient
See Figure 40
LM27341 LM27342 LM27341-Q1 LM27342-Q1 300056111.png Figure 10. Short-Circuit Release
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005654.png Figure 12. Soft Start With EN Tied to VIN
LM27341 LM27342 LM27341-Q1 LM27342-Q1 300056113.png
VIN = 12 V L = 1.5 µH Iout =1 A
VOUT = 3.3 V COUT = 44 µF
Figure 14. Bode Plot
See Figure 40
LM27341 LM27342 LM27341-Q1 LM27342-Q1 300056115.png
VIN = 5 V L = 0.56 µH Iout =1 A
VOUT = 1.2 V COUT = 68 µF
Figure 16. Bode Plot
See Figure 55
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005656.png Figure 18. Loss of Synchronization
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005629.png
Figure 20. Oscillator Frequency vs VFB
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005631.png Figure 22. VFB vs VIN
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005633.png
Figure 24. RDSON vs Temperature
LM27341 LM27342 LM27341-Q1 LM27342-Q1 30005635.png
Figure 26. IEN vs VEN