SNVS656D September   2010  – October 2016 LM3492 , LM3492-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Switching Frequency
      2. 8.3.2 LDO Regulator
      3. 8.3.3 Enable and Disable
      4. 8.3.4 Current Limit
      5. 8.3.5 Thermal Protection
      6. 8.3.6 Dynamic Headroom Control, Over-Ride, and Soft-Start
      7. 8.3.7 Current Regulator
      8. 8.3.8 Output Voltage Feedback
      9. 8.3.9 Bidirectional Communication Pin
        1. 8.3.9.1 Power-Good Indication
        2. 8.3.9.2 Overtemperature Indication
        3. 8.3.9.3 Output Current Undervoltage Indication
        4. 8.3.9.4 Switching Frequency Tuning
    4. 8.4 Device Functional Modes
    5. 8.5 Programming
      1. 8.5.1 Output Current Overvoltage Indication
      2. 8.5.2 COMM Pin Bit Pattern
      3. 8.5.3 Channel 1 Disable
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 RFB1, RFB2, and CFB
        2. 9.2.2.2 L1
        3. 9.2.2.3 D1
        4. 9.2.2.4 CIN and COUT
        5. 9.2.2.5 CVCC
        6. 9.2.2.6 CCDHC
        7. 9.2.2.7 RRT and RIREF
        8. 9.2.2.8 RCOMM
      3. 9.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Related Links
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

7 Specifications

7.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)
MIN MAX UNIT
Input voltage VIN, RT, VOUT to GND −0.3 67 V
SW to GND −0.3 67
SW to GND (Transient) −2 (<100 ns)
Output voltage ILIM to GND −0.3 0.3 V
FB to GND −0.3 5
COMM, DIM1, DIM2, to GND –0.3 6
Junction temperature, TJ 150 150 °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.

7.2 ESD Ratings

VALUE UNIT
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) ±750
(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.

7.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN MAX UNIT
Supply voltage, VIN 4.5 65 V
Operation temperature, TA –40 125 °C

7.4 Thermal Information

THERMAL METRIC(1) LM3492, LM3492-Q1 UNIT
PWP (HTSSOP)
20 PINS
RθJA Junction-to-ambient thermal resistance 36.5 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 20.8 °C/W
RθJB Junction-to-board thermal resistance 17.5 °C/W
ψJT Junction-to-top characterization parameter 0.5 °C/W
ψJB Junction-to-board characterization parameter 17.4 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance 2 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.

7.5 Electrical Characteristics

over operating free-air temperature range, VIN = 12 V (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
START-UP REGULATOR (VCC PIN)
VVCC Output voltage CVCC = 0.47 µF, no load 4.7 5.5 6.3 V
IVCC = 2 mA 4.7 5.5 6.3 V
VCC_UVLO VCC pin undervoltage lockout threshold (UVLO) VVCC increasing, TA = TJ = 25°C 3.56 3.78 4 V
VCC_UVLO-HYS VCC pin UVLO hysteresis VVCC decreasing 310 mV
IIN IIN operating current No switching, VFB = 0 V 3.6 5.2 mA
IIN-SD IIN operating current, device shutdown VEN = 0 V 30 95 µA
IVCC VCC pin current limit (1) VVCC = 0 V 18 30 mA
VCC-VOUT VCC pin output voltage when supplied by VOUT VIN = Open, IVCC = 1 mA,
VOUT = 18 V, TA = TJ = 25°C		 3.5 4.1 4.7 V
ENABLE INPUT
VEN EN pin input threshold VEN rising 1.55 1.63 1.71 V
VEN-HYS EN pin threshold hysteresis VEN falling 194 mV
IEN-SHUT Enable pullup current at shutdown VEN = 0 V 2 µA
IEN-OPER Enable pullup current during operation VEN = 2 V 40 µA
CURRENT REGULATOR
VIREF IREF pin voltage 4.5 V ≤ VIN ≤ 65 V 1.231 1.256 1.281 V
VDHC50 VIOUT under DHC IOUT = 50 mA, RIREF = 25 kΩ 0.16 0.225 0.29 V
VDHC100 IOUT = 100 mA, RIREF = 12.5 kΩ 0.38 0.48 0.58
VDHC200 IOUT = 200 mA, RIREF = 6.25 kΩ 0.81 0.99 1.17
IOUT50 Current output under DHC VIOUT = VDHC50, RIREF = 25 kΩ,
TA = TJ = 25°C		 47.5 50 52.5 mA
VIOUT = VDHC50, RIREF = 25 kΩ 46.5 50 53.5
IOUT100 VIOUT = VDHC100, RIREF = 12.5 kΩ,
TA = TJ = 25°C		 97 100 103
VIOUT = VDHC100, RIREF = 12.5 kΩ 96 100 104
IOUT200 VIOUT = VDHC200, RIREF = 6.25 kΩ,
TA = TJ = 25°C		 194 200 206
VIOUT = VDHC200, RIREF = 6.25 kΩ 192 200 208
IOUTOFF Leakage at maximum work voltage VDIM = 0, VIOUT = 65 V, TA = TJ = 25°C 5 µA
VIOUT50-MIN Minimum work voltage IOUT = 50 mA, RIREF = 25 kΩ,
IOUT = 0.98 × IOUT50, TA = TJ = 25°C		 0.1 0.15 V
VIOUT100-MIN IOUT = 100 mA, RIREF = 12.5 kΩ, IOUT = 0.98 × IOUT100,
TA = TJ = 25°C		 0.2 0.35
VIOUT200-MIN IOUT = 200 mA, RIREF = 6.25 kΩ, IOUT = 0.98 × IOUT200,
TA = TJ = 25°C		 0.4 0.65
VDIM-HIGH DIM voltage HIGH 1.17 V
VDIM-LOW DIM voltage LOW 0.7 V
BOOST CONVERTER
ICDHC-SRC CDHC pin source current VCDHC = 1.6 V, VFB = 3 V,
VIOUT = 0 V, DIM = High		 60 µA
ICDHC-SINK CDHC pin sink current VCDHC = 1.6 V, VFB = 3 V,
VIOUT = 3 V, DIM = High		 56 µA
ICDHC-LEAKAGE CDHC pin leakage current DIM = Low, VCDHC = 2.6 V, TA = TJ = 25°C 5 46 nA
ICL-MAX Integrated MOSFET peak current limit threshold 3.3 3.9 4.5 A
ICL-HALF Half integrated MOSFET peak current limit threshold RILIM = 11 kΩ 2 A
RDS(on) Integrated MOSFET On-resistance ISW = 500 mA 0.19 0.43 Ω
VFBTH-PWRGD Power-Good FB pin threshold 2.25 V
IFB Feedback pin input current VFB = 3 V, TA = TJ = 25°C 1 µA
tON ON timer pulse width VIN = 12 V, VOUT = 65 V,
RRT = 300 kΩ 		1460 ns
VIN = 24 V, VOUT = 32.5 V,
RRT = 300 kΩ 		800
VIN = 12 V, VOUT = 65 V,
RRT = 100 kΩ 		550
VIN = 24 V, VOUT = 32.5 V,
RRT = 100 kΩ 		350
tON(min)ILIM ON timer minimum pulse width at current limit 145 ns
tOFF OFF timer pulse width 145 350 ns
COMM PIN
VIOUT-OV IOUT pin overvoltage threshold COMM goes LOW during VIOUT rising, other VIOUT = 1.2 V 5.6 6.7 7.8 V
VCOMM-LOW COMM pin at LOW 5 mA into COMM 0.7 V
ILEAK-FAULT COMM pin open leakage VCOMM = 5 V 5 µA
THERMAL PROTECTION
TOTM Overtemperature indication TJ rising 135 °C
TOTM-HYS Overtemperature indication hysteresis TJ falling 15 °C
TSD Thermal shutdown temperature TJ rising 165 °C
TSD-HYS Thermal shutdown temperature hysteresis TJ falling 20 °C
(1) The VCC pin provides self bias for the internal gate drive and control circuits. Device thermal limitations limit external loading.

7.6 Typical Characteristics

Unless otherwise specified the following conditions apply: TJ = 25°C, VIN = 12 V with configuration in typical application circuit for ILED = 200 mA shown in this data sheet.
LM3492 LM3492-Q1 30116111.png Figure 1. Quiescent Current, IIN vs VIN
LM3492 LM3492-Q1 30116113.png Figure 3. VCC vs VIN
LM3492 LM3492-Q1 30116115.png Figure 5. ILED Regulation vs Temperature
LM3492 LM3492-Q1 30116117.png Figure 7. Efficiency vs VIN (ILED = 0.2 A)
LM3492 LM3492-Q1 30116119.png Figure 9. Power Up (ILED = 0.2 A)
LM3492 LM3492-Q1 30116121.png Figure 11. Steady-State Operation (ILED = 0.2 A)
LM3492 LM3492-Q1 30116123.png Figure 13. 1000:1 LED Dimming (ILED = 0.2 A,
Dimming Frequency = 200 Hz)
LM3492 LM3492-Q1 30116112.png Figure 2. VCC vs IVCC
LM3492 LM3492-Q1 30116114.png Figure 4. Switching Frequency, fSW vs VIN
LM3492 LM3492-Q1 30116116.png Figure 6. RDS(on) vs Temperature
LM3492 LM3492-Q1 30116118.png Figure 8. ILED Regulation vs VIN (ILED = 0.2 A)
LM3492 LM3492-Q1 30116120.png Figure 10. Enable Transient (ILED = 0.2 A)
LM3492 LM3492-Q1 30116122.png Figure 12. LED 50% Dimming (ILED = 0.2 A,
Dimming Frequency = 200 Hz)
LM3492 LM3492-Q1 30116124.png Figure 14. 300-ns LED Dimming Pulse Width (ILED = 0.2 A, Dimming frequency = 3.33 kHz)