SNVS508D October   2007  – September 2016 LM3405A

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 Setting the LED Current
      3. 7.3.3 Output Voltage
      4. 7.3.4 Enable Mode / Shutdown Mode
      5. 7.3.5 LED PWM Dimming
      6. 7.3.6 Undervoltage Lockout
      7. 7.3.7 Current Limit
      8. 7.3.8 Overcurrent Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Thermal Shutdown
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Inductor (L1)
      2. 8.1.2 Input Capacitor (C1)
      3. 8.1.3 Output Capacitor (C2)
      4. 8.1.4 Feed-Forward Capacitor (C4)
      5. 8.1.5 Catch Diode (D1)
      6. 8.1.6 Boost Diode (D2)
      7. 8.1.7 Boost Capacitor (C3)
      8. 8.1.8 Power Loss Estimation
    2. 8.2 Typical Applications
      1. 8.2.1 VBOOST Derived from VIN (VIN = 5 V, IF = 1 A)
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Calculate Duty Cycle (D)
          2. 8.2.1.2.2 Choose Capacitor Values (C1, C2, C3, and C4)
          3. 8.2.1.2.3 Set the Nominal LED Current (R1)
          4. 8.2.1.2.4 Choose Diodes (D1 and D2)
          5. 8.2.1.2.5 Calculate the Inductor Value (L1)
        3. 8.2.1.3 Application Curve
    3. 8.3 System Examples
      1. 8.3.1 VBOOST Derived from VOUT (VIN = 12 V, IF = 1 A)
      2. 8.3.2 VBOOST Derived from VIN through a Series Zener Diode (D3) (VIN = 15 V, IF = 1 A)
      3. 8.3.3 VBOOST Derived from VIN through a Shunt Zener Diode (D3) (VIN = 18 V, IF = 1 A)
      4. 8.3.4 LED MR16 Lamp Application (VIN = 12-V AC, IF = 0.75 A)
      5. 8.3.5 VBOOST Derived from VOUT through a Series Zener Diode (D3) ( VIN = 18 V, IF = 1 A )
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resource
    4. 11.4 Trademarks
      1. 11.3 Community Resource
      2. 11.4 Trademarks
      3. 11.5 Electrostatic Discharge Caution
      4. 11.6 Glossary
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information
  13. 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)
MIN MAX UNIT
VIN –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/DIM voltage –0.5 (VIN + 0.3) V
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.

6.2 ESD Ratings

VALUE UNIT
LM3405A IN SOT PACKAGE
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±1000
LM3405A IN MSOP-PowerPAD PACKAGE
V(ESD) Electrostatic discharge Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±750 V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

6.3 Recommended Operating Conditions

MIN MAX UNIT
VIN 3 22 V
EN/DIM voltage 0 (VIN + 0.3) V
Boost to SW voltage 2.5 5.5 V
Junction temperature –40 125 °C
ILED SOT package 400 mA
MSOP-PowerPAD package 1 A

6.4 Thermal Information

THERMAL METRIC(1) LM3405A UNIT
DDC
(SOT)		 DGN
(MSOP-PowerPAD)
6 PINS 8 PINS
RθJA Junction-to-ambient thermal resistance 182.9 55.3 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 53.4 62.8 °C/W
RθJB Junction-to-board thermal resistance 28.1 38.9 °C/W
ψJT Junction-to-top characterization parameter 1.2 8.2 °C/W
ψJB Junction-to-board characterization parameter 27.7 38.6 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance N/A 8 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.

6.5 Electrical Characteristics

Unless otherwise specified, VIN = 12 V. TYP values are for TJ = 25°C only; MIN/MAX limits apply over the junction temperature (TJ) range of –40°C to 125°C. Typical values represent the most likely parametric norm, and are provided for reference purposes only.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
VFB Feedback voltage 0.188 0.205 0.22 V
ΔVFB/(ΔVINxVFB) Feedback voltage line regulation VIN = 3 V to 22 V 0.01 %/V
IFB Feedback input bias current Sink/source 10 250 nA
UVLO Undervoltage lockout VIN Rising 2.74 2.95 V
VIN Falling 1.9 2.3 V
UVLO Hysteresis 0.44 V
fSW Switching frequency 1.2 1.6 1.9 MHz
DMAX Maximum duty cycle VFB = 0 V 85% 94%
RDS(ON) Switch ON resistance SOT (VBOOST - VSW = 3 V) 300 600 mΩ
MSOP-PowerPAD (VBOOST - VSW = 3 V) 360 700
ICL Switch current limit VBOOST - VSW = 3 V, VIN = 3 V 1.2 2 2.8 A
IQ Quiescent current Switching, VFB = 0.195 V 1.8 2.8 mA
Quiescent current (shutdown) VEN/DIM = 0 V 0.3 µA
VEN/DIM_TH Enable threshold voltage VEN/DIM Rising 1.8 V
Shutdown threshold voltage VEN/DIM Falling 0.4 V
IEN/DIM EN/DIM pin current Sink/Source 0.01 µA
ISW Switch leakage VIN = 22 V 0.1 µA

6.6 Typical Characteristics

Unless otherwise specified, VIN = 12 V, VBOOST – VSW = 5 V and TA = 25°C.
LM3405A 30015271.png
VIN = 5 V
Figure 1. Efficiency vs LED Current
LM3405A 30015232.png
IF = 0.7 A
Figure 3. Efficiency vs Input Voltage
LM3405A 30015227.png
Figure 5. VFB vs Temperature
LM3405A 30015272.png
Figure 7. Current Limit vs Temperature
LM3405A 30015234.png
Figure 9. Quiescent Current vs Temperature
LM3405A 30015231.png
IF = 1 A
Figure 2. Efficiency vs Input Voltage
LM3405A 30015233.png
IF = 0.35 A
Figure 4. Efficiency vs Input Voltage
LM3405A 30015236.png
Figure 6. Oscillator Frequency vs Temperature
LM3405A 30015230.png
VBOOST - VSW = 3 V
Figure 8. SOT RDS(ON) vs Temperature
LM3405A 30015268.png
VIN = 15 V IF = 0.2 A
Figure 10. Start-Up Response to EN/DIM Signal