SNVS891H September   2012  – September 2015 LM3642

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 Timing Requirements
    7. 6.7 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 Power Amplifier Synchronization (TX/TORCH)
      2. 7.3.2 Input Voltage Flash Monitor (IVFM)
      3. 7.3.3 Fault and Protections
        1. 7.3.3.1 Fault Operation
        2. 7.3.3.2 Flash Time-Out
        3. 7.3.3.3 Overvoltage Protection (OVP)
        4. 7.3.3.4 Current Limit
        5. 7.3.3.5 Undervoltage Lockout (UVLO)
        6. 7.3.3.6 Thermal Shutdown (TSD)
        7. 7.3.3.7 LED and/or VOUT Fault
    4. 7.4 Device Functional Modes
      1. 7.4.1 Start-up (Enabling the Device)
      2. 7.4.2 Pass Mode
      3. 7.4.3 Flash Mode
      4. 7.4.4 Torch Mode
      5. 7.4.5 Indicator Mode
    5. 7.5 Programming
      1. 7.5.1 I2C-Compatible Interface
        1. 7.5.1.1 Data Validity
        2. 7.5.1.2 Start and Stop Conditions
        3. 7.5.1.3 Transferring Data
        4. 7.5.1.4 I2C-Compatible Chip Address
        5. 7.5.1.5 Transferring Data
    6. 7.6 Register Map
      1. 7.6.1 Register Descriptions
        1. 7.6.1.1 Enable Register (0x0A)
        2. 7.6.1.2 Flags Register (0x0B)
        3. 7.6.1.3 Flash Features Register (0x08)
        4. 7.6.1.4 Current Control Register (0x09)
        5. 7.6.1.5 Input Voltage Flash Monitor (IVFM) Mode Register (0x01)
        6. 7.6.1.6 Torch Ramp Time Register (0x06)
        7. 7.6.1.7 Silicon Revision Register
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Output Capacitor Selection
        2. 8.2.2.2 Input Capacitor Selection
        3. 8.2.2.3 Inductor Selection
      3. 8.2.3 Application Curves
  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 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Trademarks
    4. 11.4 Community Resources
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)(2)(3)
MIN MAX UNIT
VIN, VSW,VOUT –0.3 6 V
VSCL, VSDA, VSTROBE, VTX, VLED –0.3 the lesser of (VIN+0.3) w/ Vmax V
Continuous power dissipation(4) Internally limited
Junction temperature (TJ-MAX) 150 °C
Maximum lead temperature (soldering)  See(5)
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) All voltages are with respect to the potential at the GND pin.
(3) If Military/Aerospace specified devices are required, contact the TI Sales Office/Distributors for availability and specifications.
(4) Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ=150°C (typical) and disengages at TJ = 135°C (typical). Thermal shutdown is verified by design.
(5) For detailed soldering specifications and information, refer to Texas Instruments Application Note 1112: DSBGA Wafer Level Chip Scale Package (SNVA009).

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)(1)
MIN MAX UNIT
VIN 2.5 5.5 V
Junction temperature (TJ) –40 125 °C
Ambient temperature (TA)(2) –40 85 °C
(1) All voltages are with respect to the potential at the GND pin.
(2) In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may have to be derated. Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP = 125°C), the maximum power dissipation of the device in the application (PD-MAX), and the junction-to-ambient thermal resistance of the part/package in the application (RθJA), as given by the following equation: TA-MAX = TJ-MAX-OP – (RθJA × PD-MAX).

6.4 Thermal Information

THERMAL METRIC(1) LM3642 UNIT
YZR (DSBGA)
9 PINS
RθJA Junction-to-ambient thermal resistance 100.0 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 0.7 °C/W
RθJB Junction-to-board thermal resistance 16.4 °C/W
ψJT Junction-to-top characterization parameter 3.2 °C/W
ψJB Junction-to-board characterization parameter 16.4 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance n/a °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953.

6.5 Electrical Characteristics

MIN and MAX limits apply over the full operating ambient temperature range (−40°C ≤ TA ≤ 85°C). Unless otherwise specified, TA = 25°C, VIN = 3.6 V.(1)(2)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
CURRENT SOURCE SPECIFICATIONS
ILED Current source accuracy 1-A flash, VOUT = 4 V –6% 1.04 6% A
1.5-A flash, VOUT = 4 V –8% 1.5 8% A
24-mA torch, VOUT = 4 V
(LM3642-LT)		 –10% 24 10% mA
48.4 mA Torch, VOUT = 4 V –10% 48.4 10% mA
VHR Current source regulation voltage ILED = 1.5 A Flash 275 12% mV
ILED = 24 mA/48.4 mA Torch 150 15%
VOVP Output overvoltage protection trip point ON threshold –2.8% 5 2.2% V
OFF threshold –2.7% 4.88 2.3%
STEP-UP DC-DC CONVERTER SPECIFICATIONS
RPMOS PMOS switch on-resistance IPMOS = 1 A 120 mΩ
RNMOS NMOS switch on-resistance INMOS = 1 A 90
ICL Input current limit –17% 1.6 15% A
–17% 1.88 15%
VIVFM Input voltage flash monitor trip threshold –3.2% 2.9 3.2% V
UVLO Undervoltage threhold Falling VIN –4% 2.8 4% V
ƒSW Switching frequency –9% 4 9% MHz
IQ Quiescent supply current Device not switching pass mode 0.75 mA
ISB Standby supply current Device disabled 2.5 V ≤ VIN ≤ 5.5 V 1.6 4 µA
tTX Flash-to-torch LED current settling time TX low to high
ILED = 1.5 A to 24 mA/48.4 mA		 4 µs
STROBE, TX VOLTAGE SPECIFICATIONS
VIL Input logic low 2.5 V ≤ VIN ≤ 5.5 V 0 0.4 V
VIH Input logic high 2.5 V ≤ VIN ≤ 5.5 V 1.2 VIN
I2C-COMPATIBLE INTERFACE SPECIFICATIONS (SCL, SDA)
VIL Input logic low 2.5 V ≤ VIN ≤ 5.5 V 0 0.4 V
VIH Input logic high 2.5 V ≤ VIN ≤ 4.2 V 1.2 VIN
VOL Output logic low ILOAD = 3 mA 400 mV
(1) All voltages are with respect to the potential at the GND pin.
(2) Minimum (Min) and Maximum (Max) limits are specified by design, test, or statistical analysis. Typical (Typ) numbers are not verified, but do represent the most likely norm. Unless otherwise specified, conditions for typical specifications are: VIN = 3.6 V and TA = 25°C.

6.6 Timing Requirements

See Figure 1.
MIN NOM MAX UNIT
t1 SCL clock frequency 2.4 ns
t2 Data In setup time to SCL High 100 ns
t3 Data out stable after SCL Low 0 ns
t4 SDA low setup time to SCL low (start) 100 ns
t5 SDA high hold time after SCL high (stop) 100 ns
LM3642 30178919.gifFigure 1. I2C-Compatible Interface Specifications

6.7 Typical Characteristics

LM3642 30178941.gifFigure 2. Flash LED Current vs. VIN
VLED = 3.8 V, ILED = 1.5 A
LM3642 30178990.gifFigure 4. High Codes Flash LED Current vs. VIN
VLED = 3.8 V, Temp = 25°C
LM3642 30178942.gifFigure 6. Torch Headroom Voltage vs. VIN
VLED = 3.7 V, ILED = 375 mA
LM3642 30178936.gifFigure 8. Peak Input Current Limit vs. VIN
VLED = 3.8V, IIN Setting = 1.9 A
LM3642 30178939.gifFigure 10. Average Input Current Limit vs. VIN
VLED = 3.8 V, IIN Setting = 1.9 A
LM3642 30178994.gifFigure 3. Torch LED Current vs. VIN
VLED = 3.7 V, ILED = 375 mA
LM3642 30178992.gifFigure 5. Flash Headroom Voltage vs. VIN
VLED = 3.8 V, ILED = 1 A
LM3642 30178935.gifFigure 7. Output Voltage vs. VIN
VLED = 3.8 V
LM3642 30178938.gifFigure 9. Peak Input Current Limit vs. VIN
VLED = 3.8 V, IIN Setting = 1.7 A
LM3642 30178940.gifFigure 11. Switching Frequency vs. VIN
VLED = 3.8 V