SNVS594G December   2008  – April 2016 LM3555

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 Control Interface 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  Synchronous Boost Converter
      2. 7.3.2  High-Side Current Source
      3. 7.3.3  I2C/EN Pin
      4. 7.3.4  SDA/EN2 and SCL/EN1 Pins
      5. 7.3.5  STROBE Pin
      6. 7.3.6  TORCH Pin
      7. 7.3.7  Indicator LED Pin (IND)
      8. 7.3.8  Internal Diode Detection
      9. 7.3.9  Fault Protections
        1. 7.3.9.1 Output Overvoltage Protection (OVP)
        2. 7.3.9.2 Output and LED Short-Circuit Protection (SCP)
        3. 7.3.9.3 Overtemperature Protection (OTP)
        4. 7.3.9.4 Flash Timeout (FTP)
        5. 7.3.9.5 Indicator Fault (IF)
        6. 7.3.9.6 Broken Inductor Fault (IP)
      10. 7.3.10 Undervoltage Lockout (UVLO)
      11. 7.3.11 Power-On Reset (POR)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Single LED Operation
      2. 7.4.2 Dual LED Operation
      3. 7.4.3 Torch or Assist (Continuous Current) Operation
      4. 7.4.4 Flash (Pulsed Current) Operation
      5. 7.4.5 Indicator Operation
      6. 7.4.6 Simple Control State Diagram
    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
    6. 7.6 Register Maps
      1. 7.6.1 Internal Registers of LM3555
      2. 7.6.2 Register Definitions
  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 Inductor Current Limit
        2. 8.2.2.2 Inductor Selection
        3. 8.2.2.3 Capacitor 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 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 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)(3)
MIN MAX UNIT
VIN −0.3 6 V
TORCH, IND, STROBE, I2C/EN, SDA/EN2, SCL/EN1 −0.3 (VIN + 0.3 V) w/ 6 V maximum V
SW 12 V
VOUT, VLED 10 V
Continuous power dissipation(4) Internally limited
Junction temperature, TJ-MAX 150 °C
Maximum lead temperature (soldering) See(5)
Storage temperature, Tstg –55 150 °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 Texas Instruments 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 specified by design.
(5) For detailed soldering specifications and information, please refer to AN-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) ±2500 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)(2)
MIN MAX UNIT
Input voltage 2.5 5.5 V
Junction temperature, TJ −30 125 °C
Ambient temperature, TA(3) −30 85 °C
(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Recommended Operating Ratings are conditions under which operation of the device is specified. Operating Ratings do not imply specified performance limits. For specified performance limits and associated test conditions, see the Electrical Characteristics tables.
(2) All voltages are with respect to the potential at the GND pin.
(3) In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may have to be de-rated. 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) LM3555 UNIT
YZR (DSBGA)
12 PINS
RθJA Junction-to-ambient thermal resistance 92.9 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 0.6 °C/W
RθJB Junction-to-board thermal resistance 16.1 °C/W
ψJT Junction-to-top characterization parameter 2.8 °C/W
ψJB Junction-to-board characterization parameter 16.1 °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

Unless otherwise specified: typical limits are for TA = 25°C; minimum and maximum limits apply over the full operating ambient temperature range (−30°C ≤ TA ≤ +85°C); VIN = 3.6 V.(1)(2)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
CURRENT AND VOLTAGE SPECIFICATIONS
ILED-OUT Flash LED accuracy 2.7 V ≤ VIN ≤ 5.5 V
VOUT = 6.5 V,
VLED = 6.2 V		 50.7
(–15.5%) 		60 67.2
(12%) 		mA (%)
69.8
(–12.8%) 		80 86.4
(8%)
304
(–5%) 		320 336
(5%)
475
(–5%) 		500 535
(7%)
IIND-OUT Indicator LED current accuracy 2.7 V ≤ VIN ≤ 5.5 V, VIND = 2 V (indicator mode) –20.4% 2.5 mA 33.6%
–20.4% 5 mA 33.8%
–20.3% 7.5 mA 33.7%
–20.2% 10 mA 33.4%
VCSH Current source headroom voltage 2.7 V ≤ VIN ≤ 5.5 V 300 350 mV
VOVP Overvoltage Protection Range 2.7 V ≤ VIN ≤ 5.5 V Trip point (rising) 9.22 9.5 9.96 V
Hysteresis 0.4
VOUT Output voltage range (VLED × NLED) + VCSH Upper range 8.5 V
Lower range 2.8
ISD Shutdown current 2.7 V ≤ VIN ≤ 5.5 V 0.75 µA
ISB Standby current 2.7 V ≤ VIN ≤ 5.5 V 1.1 4.3 µA
IQ Operating quiescent current 2.7 V ≤ VIN ≤ 5.5 V, device switching 3.5 mA
VREF Reference Voltage for LED Detection VIN = 3.6 V (No Offset) 4.35 V
VIND Indicator Fault Voltages IND OVP 2.571 V
IND Short 0.842
UVLO Undervoltage lockout Falling VIN 2.35 2.4 2.43 V
UVLOHYST UVLO hysteresis Rising VIN 60 70 85 mV
ILIM Peak current limit 2.7 V ≤ VIN ≤ 5.5 V(3) Current limit register
value = 00		 1.183 1.250 1.55 A
Current limit register
value = 01		 1.417 1.500 1.781
Current limit register
value = 10		 1.512 1.750 2.025
Current limit register
value = 11		 1.805 2 2.267
OSCILLATOR AND TIMING SPECIFICATIONS (NON-I2C INTERFACE TIMING)
ƒSW Switching frequency 2.7 V ≤ VIN ≤ 5.5 V 1.91
(−4.5%) 		2 2.15
(7.5%) 		MHz
tHW Hardware flash timeout Default timer 850 msec
tRU Current ramp-up time ILED = 0mA to ILED = fullscale,
VOUT = 6.5 V, VLED = 6.2 V		 0.6 1 msec
tRD Current ramp down time ILED = fullscale to ILED = 0 mA
VOUT = 6.5 V, VLED = 6.2 V		 0.2 0.5 msec
tTORCH-DG Torch deglitching time 6.3 9 11.7 msec
CONTROL INTERFACE VOLTAGE SPECIFICATIONS
VI2C/EN I2C/EN pin voltage threshold 2.7 V ≤ VIN ≤ 5.5 V Simple mode 0.54 V
I2C mode 1.26
VIL Low-level threshold voltage (SCL/EN1 and SDA/EN2) 2.7 V ≤ VIN ≤ 5.5 V 0.54 V
VIH High-level threshold voltage (SCL/EN1 and SDA/EN2) 2.7 V ≤ VIN ≤ 5.5 V 1.26 V
VOL Low-level output threshold limit (SDA/EN2) ILOAD = 3 mA 0.4 V
(1) Minimum (MIN) and maximum (MAX) limits are specified by design, test, or statistical analysis. Typical (TYP) numbers are not specified, but do represent the most likely norm. Unless otherwise specified, conditions for typical specifications are: VIN = 3.6 V and TA = 25°C.
(2) Switching disabled.
(3) TA (minimum) = 0°C to account for self-heating. Current Limit specification uses VIN (maximum) = 4 V to account for the input voltage range where current limit could be reached based upon the maximum application specifications for output voltage and diode current. Operation above 4 V and up to 5.5 V is allowed and must not reach current limit.

6.6 Control Interface Timing Requirements

MIN NOM MAX UNIT
TI2C-Start I2C logic start-up time (I2C/EN going high) 250 500 µsec
ƒSCL SCL clock frequency 400 kHz
tI2C I2C hang-up time 35 msec
tLOW Low Period of SCL clock 1.3 µsec
tHIGH High Period of SCL clock 0.6 µsec
tHD-STA Hold Time (repeated) START condition 0.6 µsec
tSU-STA Setup time for a repeated START condition 0.6 µsec
tHD-DAT Data hold time 0 µsec
tSU-DAT Data setup time 100 nsec
tR Rise time for SCL and SDA 300 nsec
tF Fall time for SCL and SDA 300 nsec
tSU-STO Setup time for stop condition 0.6 µsec
tBUF Bus free time between stop and start condition 1.3 µsec
tVD-DAT Data valid time 0.9 µsec
tVD-ACK Data valid acknowledge time 0.9 µsec
CB Capacitive load for each bus line 20 + 0.1 × CB 400 pF

6.7 Typical Characteristics

Unless otherwise specified: TA = 25°C; VIN = 3.6 V; CIN1= 10 µF, CIN2= 0.1 µF, COUT = 11 µF; L = 2.2 µH.
LM3555 30079421.gif
Two Series LEDs Flash
Figure 1. LED Current vs Brightness Code
LM3555 30079422.gif
Two series LEDs at 320 mA
Figure 3. Input Current vs Input Voltage
LM3555 30079427.gif
Two Series LEDs at 400 mA
Figure 5. Input Current vs Input Voltage
LM3555 30079458.gif
Two LEDs at 60 mA
Figure 7. Torch Current vs Input Voltage
LM3555 30079420.gif
Figure 9. Single LED Flash Current vs Brightness Code
LM3555 30079430.gif
One LED at 500 mA
Figure 11. Input Current vs Input Voltage
LM3555 30079453.gif
One LED at 60 mA
Figure 13. Torch Current vs Input Voltage
LM3555 30079463.gif
Figure 15. Indicator Current vs Input Voltage Brightness Codes
LM3555 30079464.gif
Figure 17. Indicator Current vs Input Voltage VLED
LM3555 30079472.gif
Figure 19. LED Current vs Input Voltage In Current Limit
LM3555 30079451.gif
Figure 21. Standby Current vs Input Voltage
LM3555 30079442.gif
Figure 23. Frequency vs Input Voltage
LM3555 30079447.gif
Two LEDs I2C Mode
Figure 25. Start-Up
LM3555 30079449.gif
Two LEDs I2C Mode
Figure 27. Ramp-Down (Zoom)
LM3555 30079467.gif
Two LEDs Simple Mode
Figure 29. Ramp-Down
LM3555 30079471.gif
Figure 31. Overvoltage Protection Fault (OVP)
LM3555 30079469.gif
Figure 33. VLED Short to GND Fault
LM3555 30079468.gif
Figure 35. Undervoltage Lockout (UVLO)
LM3555 30079444.gif
Figure 37. Edge Sensitive Strobe
LM3555 30079445.gif
Figure 39. Level Sensitive Strobe Without Timeout
LM3555 30079426.gif
Two Series LEDs at 320 mA
Figure 2. LED Current vs Input Voltage
LM3555 30079429.gif
Two series LEDs at 400 mA
Figure 4. LED Current vs Input Voltage
LM3555 30079457.gif
2 LEDs
Figure 6. Torch Current vs Brightness Code
LM3555 30079459.gif
Two LEDs at 80 mA
Figure 8. Torch Current vs Input Voltage
LM3555 30079432.gif
One LED at 500 mA
Figure 10. LED Current vs Input Voltage
LM3555 30079452.gif
One LED
Figure 12. Torch Current vs Brightness Code
LM3555 30079454.gif
One LED at 80 mA
Figure 14. Torch Current vs Input Voltage
LM3555 30079462.gif
Figure 16. Indicator Current vs Input Voltage Tri-Temp
LM3555 30079473.gif
Figure 18. Inductor Current Limit vs Input Voltage
LM3555 30079450.gif
Figure 20. Shutdown Current vs Input Voltage
LM3555 30079441.gif
Figure 22. Frequency vs Temperature
LM3555 30079474.gif
Figure 24. Flash Timeout Time vs Flash Timeout Code
LM3555 30079448.gif
Two LEDs I2C Mode
Figure 26. Ramp-Down
LM3555 30079466.gif
Two LEDs Simple Mode
Figure 28. Start-up
LM3555 30079465.gif
Two LEDs Torch
Figure 30. Diode Detect
LM3555 30079470.gif
Figure 32. VOUT Short to GND Fault
LM3555 30079475.gif
Figure 34. Broken Inductor Fault
LM3555 30079443.gif
Figure 36. Torch Deglitching Time
LM3555 30079446.gif
Figure 38. Level Sensitive Strobe With Timeout