SNVSA52E August   2014  – September 2016 LM3644

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  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 Timing Requirements
    7. 7.7 Switching Characteristics
    8. 7.8 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 Flash Mode
      2. 8.3.2 Torch Mode
      3. 8.3.3 IR Mode
    4. 8.4 Device Functioning Modes
      1. 8.4.1 Start-Up (Enabling The Device)
      2. 8.4.2 Pass Mode
      3. 8.4.3 Power Amplifier Synchronization (TX)
      4. 8.4.4 Input Voltage Flash Monitor (IVFM)
      5. 8.4.5 Fault/Protections
        1. 8.4.5.1 Fault Operation
        2. 8.4.5.2 Flash Time-Out
        3. 8.4.5.3 Overvoltage Protection (OVP)
        4. 8.4.5.4 Current Limit
        5. 8.4.5.5 NTC Thermistor Input (Torch/Temp)
        6. 8.4.5.6 Undervoltage Lockout (UVLO)
        7. 8.4.5.7 Thermal Shutdown (TSD)
        8. 8.4.5.8 LED and/or VOUT Short Fault
    5. 8.5 Programming
      1. 8.5.1 Control Truth Table
      2. 8.5.2 I2C-Compatible Interface
        1. 8.5.2.1 Data Validity
        2. 8.5.2.2 Start and Stop Conditions
        3. 8.5.2.3 Transferring Data
        4. 8.5.2.4 I2C-Compatible Chip Address
    6. 8.6 Register Descriptions
      1. 8.6.1  Enable Register (0x01)
      2. 8.6.2  IVFM Register (0x02)
      3. 8.6.3  LED1 Flash Brightness Register (0x03)
      4. 8.6.4  LED2 Flash Brightness Register (0x04)
      5. 8.6.5  LED1 Torch Brightness Register (0x05)
      6. 8.6.6  LED2 Torch Brightness Register (0x06)
      7. 8.6.7  Boost Configuration Register (0x07)
      8. 8.6.8  Timing Configuration Register (0x08)
      9. 8.6.9  TEMP Register (0x09)
      10. 8.6.10 Flags1 Register (0x0A)
      11. 8.6.11 Flags2 Register (0x0B)
      12. 8.6.12 Device ID Register (0x0C)
      13. 8.6.13 Last Flash Register (0x0D)
  9. 9 Applications 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 Output Capacitor Selection
        2. 9.2.2.2 Input Capacitor Selection
        3. 9.2.2.3 Inductor Selection
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Related Documentation
      1. 12.2.1 Related Links
      2. 12.2.2 Receiving Notification of Documentation Updates
      3. 12.2.3 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

7 Specifications

7.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)(2)
MIN MAX UNIT
IN, SW, OUT, LED1, LED2 −0.3 6 V
SDA, SCL, TX, TORCH/TEMP, HWEN, STROBE −0.3 to the lesser of (VIN+0.3) w/ 6 V max V
Continuous power dissipation(3) Internally limited
Junction temperature (TJ-MAX) 150 °C
Maximum lead temperature (soldering) See(4)
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 terminal.
(3) 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 ensured by design.
(4) For detailed soldering specifications and information, refer to TI Application Note DSBGA Wafer Level Chip Scale Package (SNVA009).

7.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2500 V
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±1500
(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)(1)(2)
MIN MAX UNIT
VIN 2.5 5.5 V
Junction temperature (TJ) −40 125 °C
Ambient temperature (TA)(3) −40 85
(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. 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 terminal.
(3) 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).

7.4 Thermal Information

THERMAL METRIC(1) LM3644 UNIT
DSBGA
12 PINS
RθJA Junction-to-ambient thermal resistance 90.2 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 0.5
RθJB Junction-to-board thermal resistance 40.0
ψJT Junction-to-top characterization parameter 3.0
ψJB Junction-to-board characterization parameter 39.2
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics.

7.5 Electrical Characteristics

Typical limits tested at TA = 25°C. Minimum and maximum limits apply over the full operating ambient temperature range (−40°C ≤ TA ≤ 85°C). Unless otherwise specified, VIN = 3.6 V, HWEN = VIN.(1)(2)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
CURRENT SOURCE SPECIFICATIONS
ILED1/2 Current source accuracy VOUT = 4 V, flash code = 0x7F = 1.5 A flash –7% 1.5 7% A
VOUT = 4 V, torch code = 0x3F = 89.3 mA torch or flash –10% 89.3 10% mA
ILED1/2 Current source accuracy (LM3644TT) VOUT = 4 V, torch code = 0x3F = 180 mA torch –10% 180 10% mA
VHR LED1 and LED2 current source regulation voltage ILED1/2 = 729 mA Flash 290 mV
ILED1/2 = 179 mA Torch 158
VHR LED1 and LED2 current source regulation voltage (LM3644TT) ILED1/2 = 360 mA Torch and flash 270 mV
VOVP ON threshold 4.86 5 5.1 V
OFF threshold 4.75 4.88 4.99
STEP-UP DC/DC CONVERTER SPECIFICATIONS
RPMOS PMOS switch on-resistance 86 mΩ
RNMOS NMOS switch on-resistance 65 mΩ
ICL Switch current limit Reg 0x07, bit[0] = 0 –12% 1.9 12% A
Reg 0x07, bit[0] = 1 –12% 2.8 12%
UVLO Undervoltage lockout threshold Falling VIN –2% 2.5 2% V
VTRIP NTC comparator trip threshold Reg 0x09, bits[3:1] = '100' –5% 0.6 5% V
INTC NTC current –6% 50 6% µA
VIVFM Input voltage flash monitor trip threshold Reg 0x02, bits[5:3] = '000' –3% 2.9 3% V
IQ Quiescent supply current Device not switching pass mode 0.3 0.75 mA
ISD Shutdown supply current Device disabled, HWEN = 0 V
2.5 V ≤ VIN ≤ 5.5 V		 0.1 4 µA
ISB Standby supply current Device disabled, HWEN = 1.8 V
2.5 V ≤ VIN ≤ 5.5 V		 2.5 10 µA
HWEN, TORCH/TEMP, STROBE, TX VOLTAGE SPECIFICATIONS
VIL Input logic low 2.5 V ≤ VIN ≤ 5.5 V 0 0.4 V
VIH Input logic high 1.2 VIN V
I2C-COMPATIBLE INTERFACE SPECIFICATIONS (SCL, SDA)
VIL Input logic low 2.5 V ≤ VIN ≤ 4.2 V 0 0.4 V
VIH Input logic high 1.2 VIN V
VOL Output logic low ILOAD = 3 mA 400 mV
(1) 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.
(2) All voltages are with respect to the potential at the GND pin.

7.6 Timing Requirements

MIN NOM MAX UNIT
t1 SCL clock period 2.4 µs
t2 Data in set-up time to SCL high 100 ns
t3 Data out stable After SCL low 0 ns
t4 SDA low set-up time to SCL Low (start) 100 ns
t5 SDA high hold time after SCL high (stop) 100 ns

7.7 Switching Characteristics

over operating free-air temperature range (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
ƒSW Switching frequency 2.5 V ≤ VIN ≤ 5.5 V –6% 4 6% MHz
LM3644 LM3644TT 30171819.gif Figure 1. I2C-Compatible Interface Specifications

7.8 Typical Characteristics

Ambient temperature is 25°C, input voltage is 3.6 V, HWEN = VIN, CIN = COUT = 2 × 10 µF and L = 1 µH, unless otherwise noted .
LM3644 LM3644TT D001_SNVS967.gif
Figure 2. LED1 Flash Current vs Brightness Code
LM3644 LM3644TT D002_SNVS967.gif
Figure 3. LED2 Flash Current vs Brightness Code
LM3644 LM3644TT D015_SNVS967.gif
Figure 4. LED1 Torch Current vs Brightness Code
LM3644 LM3644TT D040_SNVS967-LM3643.gif
LM3644TT
Figure 6. LED1 Torch Current vs Brightness Code
LM3644 LM3644TT D003_SNVS967.gif
Figure 8. LED1 Current vs Input Voltage
LM3644 LM3644TT D005_SNVS967.gif
Figure 10. LED2 Current vs Input Voltage
LM3644 LM3644TT D021_SNVS967.gif
ILED = 1.5 A ƒSW = 2 MHz Flash
Figure 12. LED1/2 Current vs Input Voltage
LM3644 LM3644TT D023_SNVS967.gif
ILED = 1 A ƒSW = 2 MHz Flash
Figure 14. LED1/2 Current vs Input Voltage
LM3644 LM3644TT D037_SNVS967.gif
ILED = 1 A ƒSW = 2 MHz Flash
Figure 16. LED1 and LED2 Current vs Input Voltage
LM3644 LM3644TT D025_SNVS967.gif
ILED = 179 mA ƒSW = 2 MHz Torch
Figure 18. LED Current vs Input Voltage
LM3644 LM3644TT D027_SNVS967.gif
ILED = 179 mA ƒSW = 2 MHz Torch
Figure 20. LED1 and LED2 Current vs Input Voltage
LM3644 LM3644TT D007_SNVS967.gif
HWEN = 0 V I2C = 0 V
Figure 22. Shutdown Current vs Input Voltage
LM3644 LM3644TT D008_SNVS967.gif
HWEN = 1.8 V I2C = 0 V
Figure 24. Standby Current vs Input Voltage
LM3644 LM3644TT D011_SNVS967.gif
ILED = 1.5 A ƒSW = 2 MHz VLED = 4.5 V
ICL = 1.9 A
Figure 26. Inductor Current Limit vs Input Voltage
LM3644 LM3644TT D013_SNVS967.gif
ILED = 1.5 A ƒSW = 2 MHz VLED = 4.5 V
ICL = 2.8 A
Figure 28. Inductor Current Limit vs Input Voltage
LM3644 LM3644TT D017_SNVS967.gif
Figure 30. 2-MHz Switching Frequency vs Input Voltage
LM3644 LM3644TT D016_SNVS967.gif
Figure 5. LED2 Torch Current vs Brightness Code
LM3644 LM3644TT D041_SNVS967-LM3643.gif
LM3644TT
Figure 7. LED2 Torch Current vs Brightness Code
LM3644 LM3644TT D004_SNVS967.gif
Figure 9. LED1 Current vs Input Voltage
LM3644 LM3644TT D006_SNVS967.gif
Figure 11. LED2 Current vs Input Voltage
LM3644 LM3644TT D022_SNVS967.gif
ILED = 1.5 A ƒSW = 4 MHz Flash
Figure 13. LED1/2 Current vs Input Voltage
LM3644 LM3644TT D024_SNVS967.gif
ILED = 730 mA ƒSW = 2 MHz Flash
Figure 15. LED1 and LED2 Current vs Input Voltage
LM3644 LM3644TT D038_SNVS967.gif
ILED = 1 A ƒSW = 4 MHz Flash
Figure 17. LED1 and LED2 Current vs Input Voltage
LM3644 LM3644TT D026_SNVS967.gif
ILED = 179 mA ƒSW = 4 MHz Torch
Figure 19. LED Current vs Input Voltage
LM3644 LM3644TT D042_SNVS967-LM3643.gif
LM3644TT ƒSW = 2 MHz Torch
ILED = 360 mA
Figure 21. LED1 and LED2 Current vs Input Voltage
LM3644 LM3644TT D009_SNVS967.gif
HWEN = VIN I2C = VIN
Figure 23. Standby Current vs Input Voltage
LM3644 LM3644TT D010_SNVS967.gif
HWEN = 1.8 V I2C = 1.8 V
Figure 25. Standby Current vs Input Voltage
LM3644 LM3644TT D012_SNVS967.gif
ILED = 1.5 A ƒSW = 4 MHz VLED = 4.5 V
ICL = 1.9 A
Figure 27. Inductor Current Limit vs Input Voltage
LM3644 LM3644TT D014_SNVS967.gif
ILED = 1.5 A ƒSW = 4 MHz VLED = 4.5 V
ICL = 2.8 A
Figure 29. Inductor Current Limit vs Input Voltage
LM3644 LM3644TT D018_SNVS967.gif
Figure 31. 4-MHz Switching Frequency vs Input Voltage