SNOSCS2D November   2013  – March 2019 LM3697

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Boost Efficiency
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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
      1. 7.1.1 PWM Input
      2. 7.1.2 HWEN Input
      3. 7.1.3 Thermal Shutdown
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Descriptions
      1. 7.3.1 High-Voltage LED Control
        1. 7.3.1.1 High-Voltage Boost Converter
        2. 7.3.1.2 High-Voltage Current Sinks (HVLED1, HVLED2 and HVLED3)
        3. 7.3.1.3 High-Voltage Current String Biasing
      2. 7.3.2 Boost Switching-Frequency Select
      3. 7.3.3 Automatic Switching Frequency Shift
      4. 7.3.4 Brightness Register Current Control
        1. 7.3.4.1 8-Bit Control (Preferred)
        2. 7.3.4.2 11-Bit Control
      5. 7.3.5 PWM Control
        1. 7.3.5.1 PWM Input Frequency Range
        2. 7.3.5.2 PWM Input Polarity
        3. 7.3.5.3 PWM Zero Detection
      6. 7.3.6 Start-up/Shutdown Ramp
      7. 7.3.7 Run-Time Ramp
      8. 7.3.8 High-Voltage Control A and B Ramp Select
    4. 7.4 Device Functional Modes
      1. 7.4.1 LED Current Mapping Modes
        1. 7.4.1.1 Exponential Mapping
          1. 7.4.1.1.1 8-Bit Code Calculation
          2. 7.4.1.1.2 11-Bit Code Calculation
        2. 7.4.1.2 Linear Mapping
          1. 7.4.1.2.1 8-Bit Code Calculation
          2. 7.4.1.2.2 11-Bit Code Calculation
      2. 7.4.2 Fault Flags/Protection Features
        1. 7.4.2.1 Open LED String (HVLED)
        2. 7.4.2.2 Shorted LED String (HVLED)
        3. 7.4.2.3 Overvoltage Protection (Inductive Boost)
        4. 7.4.2.4 Current Limit (Inductive Boost)
      3. 7.4.3 I2C-Compatible Interface
        1. 7.4.3.1 Start And Stop Conditions
        2. 7.4.3.2 I2C-Compatible Address
        3. 7.4.3.3 Transferring Data
        4. 7.4.3.4 High-Speed Mode
    5. 7.5 Register Maps
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Boost Converter Maximum Output Power
          1. 8.2.2.1.1 Peak Current Limited
          2. 8.2.2.1.2 Output Voltage Limited
        2. 8.2.2.2 Inductor Selection
        3. 8.2.2.3 Output Capacitor Selection
        4. 8.2.2.4 Schottky Diode Selection
        5. 8.2.2.5 Input Capacitor Selection
        6. 8.2.2.6 Application Circuit Component List
      3. 8.2.3 Application Performance Plots
    3. 8.3 Initialization Set Up
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Boost Output Capacitor Placement
      2. 10.1.2 Schottky Diode Placement
      3. 10.1.3 Inductor Placement
      4. 10.1.4 Boost Input Capacitor Placement
    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 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • YFQ|12
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.5 Register Maps

Table 2. LM3697 Register Descriptions

NAME ADDRESS POWER-ON RESET OPERATION
Revision 0x00 0x01 Dynamic
Software Reset 0x01 0x00 Dynamic
HVLED Current Sink Output Configuration 0x10 0x06 Static
Control A Start-up/Shutdown Ramp Time 0x11 0x00 Static
Control B Start-up/Shutdown Ramp Time 0x12 0x00 Static
Control A/B Run time Ramp Time 0x13 0x00 Static
Control A/B Run time Ramp Configuration 0x14 0x00 Static
Reserved 0x15 0x33 Static
Brightness Configuration 0x16 0x00 Static
Control A Full-Scale Current Setting 0x17 0x13 Static
Control B Full-Scale Current Setting 0x18 0x13 Static
HVLED Current Sink Feedback Enables 0x19 0x07 Static
Boost Control 0x1A 0x00 Static
Auto-Frequency Threshold 0x1B 0xCF Static
PWM Configuration 0x1C 0x0C Dynamic(1)
Control A Brightness LSB 0x20 0x00 Dynamic(2)
Control A Brightness MSB 0x21 0x00 Dynamic
Control B Brightness LSB 0x22 0x00 Dynamic(2)
Control B Brightness MSB 0x23 0x00 Dynamic
Control Bank Enables 0x24 0x00 Dynamic
HVLED Open Faults 0xB0 0x00 Production Test Only
HVLED Short Faults 0xB2 0x00 Production Test Only
LED Fault Enables 0xB4 0x00 Production Test Only
(1) The PWM inputmust always be in the inactive state when setting the Control bank PWM Enable bit. The PWM configuration bits must only be changed when the PWM is disabled for both Control Banks.
(2) The Control Brightness MSB Register must be written for the Control Brightness LSB Register value to take effect.

Table 3. Revision (Address 0x00)

Bits [7:4]
Not Used		 Bits [3:0]
Silicon Revision
Reserved 0001 = Rev. A2 Silicon

Table 4. Software Reset (Address 0x01)

Bits [7:1]
Not Used		 Bit [0]
Silicon Revision
Reserved 0 = Normal Operation
1 = Software Reset (self-clearing)

Table 5. HVLED Current Sink Output Configuration (Address 0x10)

Bits [7:3]
Not Used		 Bit [2]
HVLED3 Configuration		 Bit [1]
HVLED2 Configuration		 Bit [0]
HVLED1 Configuration
Reserved 0 = Control A
1 = Control B (default)		 0 = Control A
1 = Control B (default)		 0 = Control A (default)
1 = Control B

Table 6. Control A and B Start-up/Shutdown Ramp Time (Address 0x11 and 0x12)

Bits [7:4]
Start-up Ramp		 Bits [3:0]
Shutdown Ramp
0000 = 2048 µs (default)
0001 = 262 ms
0010 = 524 ms
0011 = 1.049 s
0100 = 2.09 s
0101 = 4.194 s
0110 = 8.389 s
0111 = 16.78 s
1000 = 33.55 s
1001 = 41.94 s
1010 = 50.33 s
1011 = 58.72 s
1100 = 67.11 s
1101 = 83.88 s
1110 = 100.66 s
1111 = 117.44 s		 0000 = 2048 µs (default)
0001 = 262 ms
0010 = 524 ms
0011 = 1.049 s
0100 = 2.097 s
0101 = 4.194 s
0110 = 8.389 s
0111 = 16.78 s
1000 = 33.55 s
1001 = 41.94 s
1010 = 50.33 s
1011 = 58.72 s
1100 = 67.11 s
1101 = 83.88 s
1110 = 100.66 s
1111 = 117.44 s

Table 7. Control A and B Run-Time Ramp Time (Address 0x13)

Bits [7:4]
Transition Time Ramp Up		 Bits [3:0]
Transition Time Ramp Down
000 = 2048 µs (default)
001 = 262 ms
010 = 524 ms
011 = 1.049 s
100 = 2.097 s
101 = 4.194 s
110 = 8.389 s
111 = 16.78 s
1000 = 33.55 s
1001 = 41.94 s
1010 = 50.33 s
1011 = 58.72 s
1100 = 67.11 s
1101 = 83.88 s
1110 = 100.66 s
1111 = 117.44 s		 000 = 2048 µs (default)
001 = 262 ms
010 = 524 ms
011 = 1.049 s
100 = 2.097 s
101 = 4.194 s
110 = 8.389 s
111 = 16.78 s
1000 = 33.55 s
1001 = 41.94 s
1010 = 50.33 s
1011 = 58.72 s
1100 = 67.11 s
1101 = 83.88 s
1110 = 100.66 s
1111 = 117.44 s

Table 8. Control A and B Run-Time Ramp Configuration (Address 0x14)

Bits [7:4]
Not Used		 Bits [3:2]
Control B Run-time Ramp Select		 Bits [1:0]
Control A Run-time Ramp Select
Reserved 00 = Control A/B Runtime Ramp Times (default)
01 = Control B Start-up/Shutdown Ramp Times
1x = 0 µs Ramp Time		 00 = Control A/B Runtime Ramp Times (default)
01 = Control A Start-up/Shutdown Ramp Times
1x = 0 µs Ramp Time

Table 9. Control A and B Brightness Configuration (Address 0x16)

Bits [7:4]
Not Used		 Bit [3]
Control B Dither Disable		 Bit [2]
Control A Dither Disable		 Bit [1]
Not Used		 Bit [0]
Control A/B Mapping Mode
Reserved 0 Enable (default)
1 Disable		 0 Enable (default)
1 Disable		 Reserved 0 Exponential (default)
1 Linear

Table 10. Control A and B Full-Scale Current Setting (Address 0x17 and 0x18)

Bits [7:5]
Not Used		 Bits [4:0]
Control A, B Full-Scale Current Select Bits
Reserved 00000 = 5 mA
10011 = 20.2 mA (default)
11111 = 29.8 mA

(0.8 mA steps, FS = 5 + code * 0.8 mA)

Table 11. HVLED Current Sink Feedback Enables (Address 0x19)

Bits [7:3]
Not Used		 Bit [2]
HVLED3 Feedback Enable		 Bit [1]
HVLED2 Feedback Enable		 Bit [0]
HVLED1 Feedback Enable
Reserved 0 = LED anode is NOT CONNECTED to COUT
1 = LED anode is CONNECTED to COUT (default)		 0 = LED anode is NOT CONNECTED to COUT
1 = LED anode is CONNECTED to COUT (default)		 0 = LED anode is NOT CONNECTED to COUT
1 = LED anode is CONNECTED to COUT (default)

Table 12. Boost Control (Address 0x1A)

Bits [7:5]
Not Used		 Bit [4]
Auto-Headroom Enable		 Bit [3]
Auto-Frequency Enable		 Bits [2:1]
Boost OVP Select		 Bit [0]
Boost Frequency Select
Reserved 0 = Disable (default)
1 = Enable		 0 = Disable (default)
1 = Enable		 00 = 16 V (default)
01 = 24 V
10 = 32 V
11 = 40 V		 0 = 500 kHz (default)
1 = 1 MHz

Table 13. Auto-Frequency Threshold (Address 0x1B)

Bits [7:0]
Auto-Frequency Threshold (default = 11001111)

Table 14. PWM Configuration (Address 0x1C)

Bits [7:4]
Not Used		 Bit [3]
PWM Zero Detection Enable		 Bit [2]
PWM Polarity		 Bit [1]
Control B PWM Enable		 Bit [0]
Control A PWM Enable
Reserved 0 = Disable
1 = Enable (default)		 0 = Active Low
1 = Active High (default)		 0 = Disable (default)
1 = Enable		 0 = Disable (default)
1 = Enable

Table 15. Control A Brightness LSB (Address 0x20)

Bits [7:3]
Not Used		 Bits [2:0]
Control A Brightness [2:0]
Reserved Brightness LSB

Table 16. Control A Brightness MSB (Address 0x21)

Bits [7:0]
Control A Brightness [11:3]
Brightness MSB
(LED current ramping does not start until the MSB is written, LSB must always be written before MSB)

Table 17. Control B Brightness LSB (Address 0x22)

Bits [7:3]
Not Used		 Bits [2:0]
Control B Brightness [2:0]
Reserved Brightness LSB

Table 18. Control B Brightness MSB (Address 0x23)

Bits [7:0]
Control B Brightness [11:3]
Brightness MSB
(LED current ramping does not start until the MSB is written, LSB must always be written before MSB)

Table 19. Control Bank Enables (Address 0x24)

Bit [7:2]
Not Used		 Bit [1]
Control B Enable		 Bit [0]
Control A Enable
Reserved 0 = Disable (default)
1 = Enable		 0 = Disable (default)
1 = Enable

Table 20. HVLED Open Faults (Address 0xB0)

Bits [7:3]
Not Used		 Bit [2]
HVLED3 Open		 Bit [1]
HVLED2 Open		 Bit [0]
HVLED1 Open
Reserved 0 = Normal Operation
1 = Open		 0 = Normal Operation
1 = Open		 0 = Normal Operation
1 = Open

Table 21. HVLED Short Faults (Address 0xB2)

Bits [7:3]
Not Used		 Bit [2]
HVLED3 Short		 Bit [1]
HVLED2 Short		 Bit [0]
HVLED1 Short
Reserved 0 = Normal Operation
1 = Short		 0 = Normal Operation
1 = Short		 0 = Normal Operation
1 = Short

Table 22. LED Fault Enable (Address 0xB4)

Bits [7:2]
Not Used		 Bit [1]
Short Faults Enable		 Bit [0]
Open Faults Enable
Reserved 0 = Disable (default)
1 = Enable		 0 = Disable (default)
1 = Enable