LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 LM3509 High Efficiency Boost for White LED's and/or OLED Displays with Dual Current Sinks and I2C Compatible Brightness Control Check for Samples: LM3509 FEATURES APPLICATIONS • • 1 2 • • • • • • • • • • • • • Integrated OLED Display Power Supply and LED Driver Drives up to 10 LED’s at 30mA Drives up to 5 LED’s at 20mA and Delivers up to 21V at 40mA Over 90% Efficient 32 Exponential Dimming Steps 0.15% Accurate Current Matching Between Strings Internal Soft-Start Limits Inrush Current True Shutdown Isolation for LED’s Wide 2.7V to 5.5V Input Voltage Range 21V Over-Voltage Protection 1.27MHz Fixed Frequency Operation Low Profile 10-Pin WSON Package (3mm x 3mm x 0.8mm) General Purpose I/O Active Low Hardware Reset • • Dual Display LCD Backlighting for Portable Applications Large Format LCD Backlighting OLED Panel Power Supply DESCRIPTION The LM3509 current mode boost converter offers two separate outputs. The first output (MAIN) is a constant current sink for driving series white LED’s. The second output (SUB/FB) is configurable as a constant current sink for series white LED bias, or as a feedback pin to set a constant output voltage for powering OLED panels. Typical Application Circuits 10 PH 30 mA per string 2.7V to 5.5V CIN IN 1 PF SW OVP LM3509 COUT 1 PF VIO 10 k: 10 k: SCL SDA MAIN SUB/FB RESET/GPIO SET GND RSET 8 k: Dual White LED Bias Supply 1 2 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2007–2013, Texas Instruments Incorporated LM3509 SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 www.ti.com DESCRIPTION (CONTINUED) When configured as a dual output white LED bias supply, the LM3509 adaptively regulates the supply voltage of the LED strings to maximize efficiency and insure the current sinks remain in regulation. The maximum current per output is set via a single external low power resistor. An I2C compatible interface allows for independent adjustment of the LED current in either output from 0 to max current in 32 exponential steps. When configured as a white LED + OLED bias supply the LM3509 can independently and simultaneously drive a string of up to 5 white LED’s and deliver a constant output voltage of up to 21V for OLED panels. Output over-voltage protection shuts down the device if VOUT rises above 21V allowing for the use of small sized low voltage output capacitors. The LM3509 is offered in a small 10-pin thermally- enhanced WSON package and operates over the -40°C to +85°C temperature range. 2 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 10 PH 2.7V to 5.5V CIN VOLED = 18V SW IN 1 PF OVP COUT 2.2 PF LM3509 R1 140 k: 20 mA 40 mA VIO 10 k: OLED Display 10 k: SCL SDA MAIN SUB/FB RESET/GPIO SET R2 10 k: RSET 12 k: GND OLED Panel Power Supply Connection Diagram Top View BOTTOM VIEW TOP VIEW 1 10 10 1 2 9 9 2 8 8 4 7 7 4 5 6 6 5 3 DAP DAP 3 Figure 1. 10-Pin WSON (3mm × 3mm × 0.8mm) PIN DESCRIPTIONS Pin Name 1 MAIN Function 2 SUB/FB 3 SET LED Current Setting Connection. Connect a resistor from SET to GND to set the maximum LED current into MAIN or SUB/FB (when in LED mode), where ILED_MAX = 192×1.244V/RSET. 4 VIO Logic Voltage Level Input 5 RESET/GPIO 6 SW Drain Connection for Internal NMOS Switch 7 OVP Over-Voltage Protection Sense Connection. Connect OVP to the positive terminal of the output capacitor. 8 IN Main Current Sink Input. Secondary Current Sink Input or 1.25V Feedback Connection for Constant Voltage Output. Active Low Hardware Reset and Programmable General Purpose I/O. Input Voltage Connection. Connect IN to the input supply, and bypass to GND with a 1µF ceramic capacitor. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 3 LM3509 SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 www.ti.com PIN DESCRIPTIONS (continued) Pin Name 9 SDA Serial Data Input/Output Function 10 SCL Serial Clock Input DAP GND Ground These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. Absolute Maximum Ratings (1) (2) (3) −0.3V to 6V VIN VSW, VOVP, −0.3V to 25V VSUB/FB, VMAIN −0.3V to 23V −0.3V to 6V VSCL, VSDA, VRESET\GPIO, VIO , VSET Continuous Power Dissipation Internally Limited Junction Temperature (TJ-MAX) +150ºC Storage Temperature Range -65ºC to +150º C Maximum Lead Temperature (Soldering, 10s) (4) +300°C ESD Rating (5) Human Body Model (1) (2) (3) (4) (5) 2.5kV Absolute maximum ratings are limits beyond which damages to the device may occur. Operating Ratings are conditions for which the device is intended to be functional, but device parameter specifications may not be ensured. For ensured specifications and test conditions, see the Electrical Characteristics. If Military/Aerospace specified devices are required, please contact the Texas Instrument Sales Office/ Distributors for availability and specifications. All voltages are with respect to the potential at the GND pin. For detailed soldering specifications and information, please refer to Application Note 1187: Leadless Lead frame Package (AN-1187) (Literature Number SNOA401). The human body model is a 100pF capacitor discharged through 1.5kΩ resistor into each pin. (MIL-STD-883 3015.7). Operating Ratings (1) (2) VIN 2.7V to 5.5V VSW, VOVP, 0V to 23V VSUB/FB, VMAIN 0V to 21V (3) -40ºC to +110ºC Ambient Temperature Range (TA) (4) -40ºC to +85ºC Junction Temperature Range (TJ) (1) (2) (3) (4) Absolute maximum ratings are limits beyond which damages to the device may occur. Operating Ratings are conditions for which the device is intended to be functional, but device parameter specifications may not be ensured. For ensured specifications and test conditions, see the Electrical Characteristics. All voltages are with respect to the potential at the GND pin. Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ=150ºC (typ.) and disengages at TJ=140ºC (typ.). 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 = +105ºC), 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 (θJA), as given by the following equation: TA-MAX = TJ-MAX-OP – (θJA × PD-MAX). Thermal Properties Junction to Ambient Thermal Resistance (θJA) (1) (1) 4 54°C/W Junction-to-ambient thermal resistance (θJA) is taken from a thermal modeling result, performed under the conditions and guidelines set forth in the JEDEC standard JESD51-7. The test board is a 4-layer FR-4 board measuring 114mm x 76mm x 1.6mm with a 2x1 array of thermal vias. The ground plane on the board is 113mm x 75mm. Thickness of copper layers are 71.5µm/35µm/35µm/71.5µm (2oz/1oz/1oz/2oz). Ambient temperature in simulation is 22°C, still air. Power dissipation is 1W. The value of θJA of this product in the WSON package could fall in a range as wide as 50ºC/W to 150ºC/W (if not wider), depending on board material, layout, and environmental conditions. In applications where high maximum power dissipation exists special care must be paid to thermal dissipation issues. For more information on these topics, please refer to Application Note 1187: Leadless Leadframe Package (LLP) (Literature Number SNOA401). Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 Electrical Characteristics Specifications in standard type face are for TA = 25°C and those in boldface type apply over the Operating Temperature Range of TA = −40°C to +85°C. Unless otherwise specified VIN = 3.6V, VIO = 1.8V, VRESET/GPIO = VIN, VSUB/FB = VMAIN = 0.5V, R = 12.0kΩ, OLED = ‘0’, ENM = ENS = ‘1’, BSUB = BMAIN = Full Scale. (1) (2) SET Symbol ILED Parameter Conditions Output Current Regulation MAIN or SUB/FB Enabled UNI = ‘0’, or ‘1’ Maximum Current Per Current Sink RSET = 8.0kΩ Min 18.6 Typ Max 20 21.8 30 Units mA (3) ILED-MATCH IMAIN to ISUB/FB Current Matching UNI = ‘1’ VSET SET Pin Voltage 3.0V < VIN < 5V ILED/ISET ILED Current to ISET Current Ratio 192 VREG_CS Regulated Current Sink Headroom Voltage 500 VREG_OLED VSUB/FB Regulation Voltage in 3.0V < VIN < 5.5V, OLED = OLED Mode ‘1’ VHR Current Sink Minimum Headroom Voltage RDSON NMOS Switch On Resistance ISW = 100mA ICL NMOS Switch Current Limit VIN = 3.0V 650 VOVP Output Over-Voltage Protection ON Threshold OFF Threshold 0.15 1 % 1.244 1.172 ILED = 95% of nominal 1.21 V mV 1.239 300 V mV Ω 0.58 770 875 21.2 22 22.9 19.7 20.6 21.2 1.0 1.27 1.4 mA V fSW Switching Frequency DMAX Maximum Duty Cycle 90 % DMIN Minimum Duty Cycle 10 % IQ Quiescent Current, Device Not Switching ISHDN Shutdown Current MHz VMAIN and VSUB/FB > VREG_CS, BSUB = BMAIN = 0x00 400 VSUB/FB > VREG_OLED, OLED=’1’, ENM=ENS=’0’ 250 305 ENM = ENS = OLED = '0' 3.6 5 µA 0.5 V 440 µA RESET/GPIO Pin Voltage Specifications VIL Input Logic Low 2.7V < VIN <5.5V, MODE bit =0 VIH Input Logic High 2.7V < VIN < 5.5V, MODE bit =0 VOL Output Logic Low ILOAD=3mA, MODE bit = 1 1.1 V 400 mV VIN V 0.36×VIO V 2 I C Compatible Voltage Specifications (SCL, SDA, VIO) VIO Serial Bus Voltage Level 2.7V < VIN < 5.5V VIL Input Logic Low 2.7V < VIN < 5.5V VIH Input Logic High 2.7V < VIN < 5.5V VOL Output Logic Low ILOAD = 3mA (4) 1.4 0.7×VIO VIO V 400 mV I2C Compatible Timing Specifications (SCL, SDA, VIO, seeFigure 2) (5) (4) t1 SCL Clock Period 2.5 µs t2 Data In Setup Time to SCL High 100 ns (1) (2) (3) (4) (5) All voltages are with respect to the potential at the GND pin. Min and Max limits are specified by design, test, or statistical analysis. Typical (Typ) numbers are not specified, but represent the most likely norm. The matching specification between MAIN and SUB is calculated as 100 × ((IMAIN or ISUB) - IAVE) / IAVE. This simplifies out to be 100 × (IMAIN - ISUB)/(IMAIN + ISUB). SCL and SDA signals are referenced to VIO and GND for minimum VIO voltage testing. SCL and SDA must be glitch-free in order for proper brightness control to be realized. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 5 LM3509 SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 www.ti.com Electrical Characteristics (continued) Specifications in standard type face are for TA = 25°C and those in boldface type apply over the Operating Temperature Range of TA = −40°C to +85°C. Unless otherwise specified VIN = 3.6V, VIO = 1.8V, VRESET/GPIO = VIN, VSUB/FB = VMAIN = 0.5V, R = 12.0kΩ, OLED = ‘0’, ENM = ENS = ‘1’, BSUB = BMAIN = Full Scale.(1) (2) SET Symbol t3 t4 t5 Parameter Conditions Data Out Stable After SCL Low Min Typ Max Units 0 ns SDA Low Setup Time to SCL Low (Start) 100 ns SDA High Hold Time After SCL High (Stop) 100 ns t1 t5 t4 t2 t3 Figure 2. I2C Timing 6 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 Typical Performance Characteristics VIN = 3.6V, LEDs are OSRAM (LW M67C), COUT = 1µF (LED Mode), COUT = 2.2µF (OLED Mode), CIN = 1µF, L = TDK VLF4012AT-100MR79, (RL = 0.3Ω), RSET = 8.06kΩ, UNI = '1', ILED = ISUB + IMAIN, TA = +25°C unless otherwise specified. 10 LED Efficiency vs ILED (2 Strings of 5LEDs) 8 LED Efficiency vs ILED (2 Strings of 4LEDs) Figure 3. Figure 4. 6 LED Efficiency vs ILED (2 Strings of 3LEDs) 4 LED Efficiency vs ILED (2 Strings of 2LEDs) Figure 5. Figure 6. LED Efficiency vs VIN (L = TDK VLF3012AT-100MR49, RL = 0.36Ω, ILED = 40mA) LED Efficiency vs VIN (L = TDK VLF5014AT-100MR92, RL = 0.2Ω, ILED = 60mA) Figure 7. Figure 8. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 7 LM3509 SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) VIN = 3.6V, LEDs are OSRAM (LW M67C), COUT = 1µF (LED Mode), COUT = 2.2µF (OLED Mode), CIN = 1µF, L = TDK VLF4012AT-100MR79, (RL = 0.3Ω), RSET = 8.06kΩ, UNI = '1', ILED = ISUB + IMAIN, TA = +25°C unless otherwise specified. 8 18V OLED Efficiency vs IOUT 12V OLED Efficiency vs IOUT Figure 9. Figure 10. LED Line Regulation (UNI = '0') OLED Line Regulation IOLED = 60mA Figure 11. Figure 12. OLED Line Regulation IOLED = 60mA OLED Load Regulation VOLED = 18V Figure 13. Figure 14. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 Typical Performance Characteristics (continued) VIN = 3.6V, LEDs are OSRAM (LW M67C), COUT = 1µF (LED Mode), COUT = 2.2µF (OLED Mode), CIN = 1µF, L = TDK VLF4012AT-100MR79, (RL = 0.3Ω), RSET = 8.06kΩ, UNI = '1', ILED = ISUB + IMAIN, TA = +25°C unless otherwise specified. OLED Load Regulation VOLED = 12V Peak Current Limit vs. VIN Figure 15. Figure 16. Over Voltage Limit vs. VIN Switch On-Resistance vs. VIN Figure 17. Figure 18. Switching Frequency vs. VIN Maximum Duty Cycle vs. VIN Figure 19. Figure 20. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 9 LM3509 SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) VIN = 3.6V, LEDs are OSRAM (LW M67C), COUT = 1µF (LED Mode), COUT = 2.2µF (OLED Mode), CIN = 1µF, L = TDK VLF4012AT-100MR79, (RL = 0.3Ω), RSET = 8.06kΩ, UNI = '1', ILED = ISUB + IMAIN, TA = +25°C unless otherwise specified. (1) 10 Shutdown Current vs. VIN Switching Supply Current vs. VIN Figure 21. Figure 22. LED Current Matching vs. CODE (1) (UNI = '1', RSET = 12kΩ, TA = -40°C to +85°C) LED Current Accuracy vs CODE (RSET = 12kΩ±0.05%) Figure 23. Figure 24. LED Current vs CODE (IMAIN, ISUB, IIDEAL, RSET = 12kΩ±0.05%) ILED vs Current Source Headroom Voltage (VIN = 3V, UNI = '0') Figure 25. Figure 26. The matching specification between MAIN and SUB is calculated as 100 × ((IMAIN or ISUB) - IAVE) / IAVE. This simplifies out to be 100 × (IMAIN - ISUB)/(IMAIN + ISUB). Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 Typical Performance Characteristics (continued) VIN = 3.6V, LEDs are OSRAM (LW M67C), COUT = 1µF (LED Mode), COUT = 2.2µF (OLED Mode), CIN = 1µF, L = TDK VLF4012AT-100MR79, (RL = 0.3Ω), RSET = 8.06kΩ, UNI = '1', ILED = ISUB + IMAIN, TA = +25°C unless otherwise specified. Start-Up Waveform (LED Mode) (2 × 5 LEDs, 30mA per string) Start-Up Waveform (OLED Mode) (VOUT = 18V, IOUT = 60mA) Channel 1: SDA (5V/div) Channel 2: VOUT (10V/div) Channel 3: ILED (50mA/div) Channel 4: IIN (500mA/div) Time Base: 400µs/div Channel 1: SDA (5V/div) Channel 2: VOUT (10V/div) Channel 3: IOUT (50mA/div) Channel 4: IIN (500mA/div) Time Base: 400µs/div Figure 27. Figure 28. Load Step (OLED Mode) (VOUT = 18V, COUT = 2.2µF) Line Step (LED Mode) (2 × 5 LEDs, 30mA per String, COUT = 1µF) Channel 1: VOUT (AC Coupled, 500mV/div) Channel 2: IOUT (20mA/div) Time Base: 200µs/div Figure 29. Channel 1: VOUT (AC Coupled, 500mV/div) Channel 2: VIN (AC Coupled, 500mV/div) Time Base: 200µs/div Figure 30. Transition From OLED to OLED + 1 × 4 LED) (VOUT = 18V, IOUT = 40mA, ILED = 20mA, COUT = 2.2µF) Channel 3: SDA (2V/div) Channel 1: VOUT (AC Coupled, 200mV/div) Channel 2: IMAIN (20mA/div) Time Base: 400µs/div Figure 31. RESET Functionality Channel 2: ISUB (20mA/div) Channel R1: IMAIN (20mA/div) Channel 1: RESET (2V/div) Time Base: 200ns/div Figure 32. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 11 LM3509 SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) VIN = 3.6V, LEDs are OSRAM (LW M67C), COUT = 1µF (LED Mode), COUT = 2.2µF (OLED Mode), CIN = 1µF, L = TDK VLF4012AT-100MR79, (RL = 0.3Ω), RSET = 8.06kΩ, UNI = '1', ILED = ISUB + IMAIN, TA = +25°C unless otherwise specified. GPIO Functionality (GPIO Configured as OUTPUT, fSCL = 200kHz) Channel 2: GPIO (2V/div) Channel 3: SDA (2V/div) Channel 1:SCL (2V/div) Time Base: 40µs/div Ramp Rate Functionality (RMP1, RMP0 = '00') Channel 3: SDA (2V/div) Channel 1: IMAIN (10mA/div) Channel 4: ISUB (10mA/div) Time Base: 40µs/div Figure 33. Figure 34. Ramp Rate Functionality (RMP1, RMP0 = '01') Ramp Rate Functionality (RMP1, RMP0 = '10') Channel 1:IMAIN (10mA/div) Channel 4: ISUB (10mA/div) Time Base: 200ms/div Channel 3: SDA (2V/div) Channel 1: IMAIN (10mA/div) Channel 4: ISUB (10mA/div) Time Base: 100ms/div Figure 35. Figure 36. Ramp Rate Functionality (RMP1, RMP0 = '11') Channel 1:IMAIN (10mA/div) Channel 4: ISUB (10mA/div) Time Base: 400ms/div Figure 37. 12 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 BLOCK DIAGRAM OVP MUX IN SOFT START ERROR AMP S0 500 mV S1 1.22V Thermal shutdown Light Load SW OVP OLED R RZ R S R R 0.5: R Driver CC Osc/ Ramp Over Current Protection RESET/ GPIO ¦ MAIN MIN MUX S0 IMAIN S1 VIO OLED SCL SDA 1.244V ILED_MAX = SET 1.244V RSET SUB/FB 5 BIT CONTROL 2 I C/ CONTROL 5 BIT CONTROL ISUB/FB 192 GND Figure 38. LM3509 Block Diagram OPERATION DESCRIPTION The LM3509 Current Mode PWM boost converter operates from a 2.7V to 5.5V input and provides two regulated outputs for White LED and OLED display biasing. The first output, MAIN, provides a constant current of up to 30mA to bias up to 5 series white LED’s. The second output, SUB/FB, can be configured as a current source for up to 5 series white LED’s at at 30mA, or as a feedback voltage pin to regulate a constant output voltage of up to 21V. When both MAIN and SUB/FB are configured for white LED bias the current for each LED string is controlled independently or in unison via an I2C compatible interface. When MAIN is configured for white LED bias and SUB/FB is configured as a feedback voltage pin, the current into MAIN is controlled via the I2C compatible interface and SUB/FB becomes the middle tap of a resistive divider used to regulate the output voltage of the boost converter. The core of the LM3509 is a Current Mode Boost converter. Operation is as follows. At the start of each switching cycle the internal oscillator sets the PWM converter. The converter turns the NMOS switch on, allowing the inductor current to ramp while the output capacitor supplies power to the white LED’s and/or OLED panel. The error signal at the output of the error amplifier is compared against the sensed inductor current. When the sensed inductor current equals the error signal, or when the maximum duty cycle is reached, the NMOS switch turns off causing the external Schottky diode to pick up the inductor current. This allows the inductor current to ramp down causing its stored energy to charge the output capacitor and supply power to the load. At the end of the clock period the PWM controller is again set and the process repeats itself. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 13 LM3509 SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 www.ti.com Adaptive Regulation When biasing dual white led strings (White LED mode) the LM3509 maximizes efficiency by adaptively regulating the output voltage. In this configuration the 500mV reference is connected to the non-inverting input of the error amplifier via mux S2 (see Figure 38). The lowest of either VMAIN or VSUB/FB is then applied to the inverting input of the error amplifier via mux S1. This ensures that VMAIN and VSUB/FB are at least 500mV, thus providing enough voltage headroom at the input to the current sinks for proper current regulation. In the instance when there are unequal numbers of LEDs or unequal currents from string to string, the string with the highest voltage will be the regulation point. Unison/Non-Unison Mode Within White LED mode there are two separate modes of operation, Unison and Non-Unison. Non-Unison mode provides for independent current regulation, while Unison mode gives up independent regulation for more accurate matching between LED strings. When in Non-Unison mode the LED currents IMAIN and ISUB/FB are independently controlled via registers BMAIN and BSUB respectively (see Brightness Registers (BMAIN and BSUB) section). When in Unison mode BSUB is disabled and both IMAIN and ISUB/FB are controlled via BMAIN only. Start-Up The LM3509 features an internal soft-start, preventing large inrush currents during start-up that can cause excessive voltage ripple on the input. For the typical application circuits when the device is brought out of shutdown the average input current ramps from zero to 450mA in 1.2ms. See Start Up Plots in the Typical Performance Characteristics. OLED Mode When the LM3509 is configured for a single White LED bias + OLED display bias (OLED mode), the noninverting input of the error amplifier is connected to the internal 1.21V reference via MUX S2. MUX S1 switches SUB/FB to the inverting input of the error amplifier while disconnecting the internal current sink at SUB/FB. The voltage at MAIN is not regulated in OLED mode so when the application requires white LED + OLED panel biasing, ensure that at least 300mV of headroom is maintained at MAIN to guarantee proper regulation of IMAIN. (see the Typical Performance Characteristics for a plot of ILED vs Current Source Headroom Voltage) Peak Current Limit The LM3509’s boost converter has a peak current limit for the internal power switch of 770mA typical (650mA minimum). When the peak switch current reaches the current limit the duty cycle is terminated resulting in a limit on the maximum output current and thus the maximum output power the LM3509 can deliver. Calculate the maximum LED current as a function of VIN, VOUT, L and IPEAK as: (IPEAK IOUT_MAX = where 'IL = 'IL) u K u VIN VOUT VIN u (VOUT VIN) 2 u fSW u L u VOUT (1) ƒSW = 1.27MHz. Typical values for efficiency and IPEAK can be found in the efficiency and IPEAK curves in the Typical Performance Characteristics. Over Voltage Protection The LM3509's output voltage (VOUT) is limited on the high end by the Output Over-Voltage Protection Threshold (VOVP) of 21.2V. In White LED mode during output open circuit conditions the output voltage will rise to the over voltage protection threshold (VOVP = 21.2V min). When this happens the controller will stop switching causing VOUT to droop. When the output voltage drops below 19.7V (min) the device will resume switching. If the device remains in an over voltage condition the LM3509 will repeat the cycle causing the output to cycle between the high and low OVP thresholds. See waveform for OVP condition in the Typical Performance Characteristics. 14 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 Output Current Accuracy and Current Matching The LM3509 provides both precise current accuracy (% error from ideal value) and accurate current matching between the MAIN and SUB/FB current sinks. Two modes of operation affect the current matching between IMAIN and ISUB/FB. The first mode (Non-Unison mode) is set by writing a 0 to bit 2 of the General Purpose register (UNI bit). Non-Unison mode allows for independent programming of IMAIN and ISUB/FB via registers BMAIN and BSUB respectively. In this mode typical matching between current sinks is 1%. Writing a 1 to UNI configures the device for Unison mode. In Unison mode, BSUB is disabled and IMAIN and ISUB/FB are both controlled via register BMAIN. In this mode typical matching is 0.15%. Light Load Operation The LM3509 boost converter operates in three modes; continuous conduction, discontinuous conduction, and skip mode operation. Under heavy loads when the inductor current does not reach zero before the end of the switching period the device switches at a constant frequency. As the output current decreases and the inductor current reaches zero before the end of the switching cycle, the device operates in discontinuous conduction. At very light loads the LM3509 will enter skip mode operation causing the switching period to lengthen and the device to only switch as required to maintain regulation at the output. Active Low Reset/General Purpose I/O (RESET\GPIO) The RESET/GPIO serves as an active low reset input or as a general-purpose logic input/output. Upon power-up of the device RESET/GPIO defaults to the active low reset mode. The functionality of RESET/GPIO is set via the GPIO register and is detailed in Table 6. When configured as an active low reset input, (Bit 0 = 0), pulling RESET/GPIO low automatically programs all registers of the LM3509 with 0x00. Their state cannot be changed until RESET/GPIO is pulled high. The General Purpose I/O (GPIO) register is used to enable the GPIO function of the RESET/GPIO pin. The GPIO register is an 8-bit register with only the 3 LSB’s active. The 5 MSB’s are not used. When configured as an output, RESET/GPIO is open drain and requires an external pull-up resistor. Thermal Shutdown The LM3509 offers a thermal shutdown protection. When the die temperature reaches +140°C the device will shutdown and not turn on again until the die temperature falls below +120°C. I2C Compatible Interface The LM3509 is controlled via an I2C compatible interface. START and STOP conditions classify the beginning and the end of the I2C session. A START condition is defined as SDA transitioning from HIGH to LOW while SCL is HIGH. A STOP condition is defined as SDA transitioning from LOW to HIGH while SCL is HIGH. The I2C master always generates START and STOP conditions. The I2C bus is considered busy after a START condition and free after a STOP condition. During data transmission, the I2C master can generate repeated START conditions. A START and a repeated START conditions are equivalent function-wise. The data on SDA must be stable during the HIGH period of the clock signal (SCL). In other words, the state of SDA can only be changed when SCL is LOW. SDA SCL S P Start Condition Stop Condition Figure 39. Start and Stop Sequences Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 15 LM3509 SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 www.ti.com I2C Compatible Address The chip address for the LM3509 is 0110110 (36h). After the START condition, the I2C master sends the 7-bit chip address followed by a read or write bit (R/W). R/W= 0 indicates a WRITE and R/W = 1 indicates a READ. The second byte following the chip address selects the register address to which the data will be written. The third byte contains the data for the selected register. MSB 0 Bit 7 LSB 1 Bit 6 1 Bit 5 0 Bit 4 1 Bit 3 1 Bit 2 0 Bit 1 R/W Bit 0 2 I C Slave Address (chip address) Figure 40. Chip Address Transferring Data Every byte on the SDA line must be eight bits long, with the most significant bit (MSB) transferred first. Each byte of data must be followed by an acknowledge bit (ACK). The acknowledge related clock pulse (9th clock pulse) is generated by the master. The master releases SDA (HIGH) during the 9th clock pulse. The LM3509 pulls down SDA during the 9th clock pulse, signifying an acknowledge. An acknowledge is generated after each byte has been received. Figure 41 is an example of a write sequence to the General Purpose register of the LM3509. SCL SDA Chip Address (36h) START R/W ACK Register Address (10h) ACK Register Data (06h) ACK STOP Figure 41. Write Sequence to the LM3509 Register Descriptions There are 4, 8 bit registers within the LM3509 as detailed in Table 1. Table 1. LM3509 Register Descriptions Hex Address Power -On-Value General Purpose (GP) Register Name 10 0xC0 Brightness Main (BMAIN) A0 0xE0 Brightness Sub (BSUB) B0 0xE0 General Purpose I/O (GPIO) 80 0XF8 General Purpose Register (GP) The General Purpose register has four functions. It controls the on/off state of MAIN and SUB/FB, it selects between Unison or Non-Unison mode, provides for control over the rate of change of the LED current (see Brightness Rate of Change Description), and selects between White LED and OLED mode. Figure 42 and Table 2 describes each bit available within the General Purpose Register. 16 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 General Purpose Register Register Address 0x10 MSB 1 Bit 7 1 Bit 6 OLED Bit 5 RMP1 Bit 4 RMP0 Bit 3 LSB UNI Bit 2 ENS Bit 1 ENM Bit 0 Figure 42. General Purpose Register Description Table 2. General Purpose Register Bit Function Bit Name Function Power-On-Value 0 ENM Enable MAIN. Writing a 1 to this bit enables the main current sink (MAIN). Writing a 0 to this bit disables the main current sink and forces MAIN high impedance. 0 1 ENS Enable SUB/FB. Writing a 1 to this bit enables the secondary current sink (SUB/FB). Writing a 0 to this bit disables the secondary current sink and forces SUB/FB high impedance. 0 2 UNI Unison Mode Select. Writing a 1 to this bit disables the BSUB register and causes the contents of BMAIN to set the current in both the MAIN and SUB/FB current sinks. Writing a 0 to this bit allows the current into MAIN and SUB/FB to be independently controlled via the BMAIN and BSUB registers respectively. 0 3 RMP0 RMP1 Brightness Rate of Change. Bits RMP0 and RMP1 set the rate of change of the LED current into MAIN and SUB/FB in response to changes in the contents of registers BMAIN and BSUB (see Brightness Rate of Change Description). 0 4 5 OLED OLED = 0 places the LM3509 in White LED mode. In this mode both the MAIN and SUB/FB current sinks are active. The boost converter ensures there is at least 500mV at VMAIN and VSUB/FB. OLED = 1 places the LM3509 in OLED mode. In this mode the boost converter regulates VSUB/FB to 1.25V. VMAIN is unregulated and must be > 400mV for the MAIN current sink to maintain current regulation. 0 6 Don't Care These are non-functional read only bits. They will always read back as a 1. 1 0 7 Table 3. Operational Truth Table UNI OLED ENM ENS Result X 0 0 0 LM3509 Disabled 1 0 1 X MAIN and SUB/FB current sinks enabled. Current levels set by contents of BMAIN. 1 0 0 X MAIN and SUB/FB Disabled 0 0 0 1 SUB/FB current sink enabled. Current level set by BSUB. 0 0 1 0 MAIN current sink enabled. Current level set by BMAIN. 0 0 1 1 MAIN and SUB/FB current sinks enabled. Current levels set by contents of BMAIN and BSUB respectively. X 1 1 X SUB/FB current sink disabled (SUB/FB configured as a feedback pin). MAIN current sink enabled current level set by BMAIN. X 1 0 X SUB/FB current sink disabled (SUB/FB configured as a feedback pin). MAIN current sink disabled. * ENM ,ENS, or OLED high enables analog circuitry. Brightness Registers (BMAIN and BSUB) With the UNI bit (General Purpose register) set to 0 (Non-Unison mode) both brightness registers (BMAIN and BSUB) independently control the LED currents IMAIN and ISUB/FB respectively. BMAIN and BSUB are both 8 bit, but with only the 5 LSB’s controlling the current. The three MSB’s are don’t cares. The LED current control is designed to approximate an exponentially increasing response of the LED current vs increasing code in either BMAIN or BSUB (see Figure 45). Program ILED_MAX by connecting a resistor (RSET) from SET to GND, where: Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 17 LM3509 SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 ILED_MAX = 192 u www.ti.com 1.244V RSET (2) With the UNI bit (General Purpose register) set to 1 (Unison mode), BSUB is disabled and BMAIN sets both IMAIN and ISUB/FB. This prevents the independent control of IMAIN and ISUB/FB, however matching between current sinks goes from typically 1%(with UNI = 0) to typically 0.15% (with UNI = 1). Figure 43 and Figure 44 show the register descriptions for the Brightness MAIN and Brightness SUB registers. Table 4 and Figure 45 show IMAIN and/or ISUB/FB vs. brightness data as a percentage of ILED_MAX. Brightness Main Register Register Address 0xA0 MSB 1 Bit 7 1 Bit 6 1 Bit 5 Data Bit 4 Data Bit 3 LSB Data Bit 2 Data Bit 1 Data Bit 0 Figure 43. Brightness MAIN Register Description Brightness Sub Register Register Address 0xB0 MSB 1 Bit 7 1 Bit 6 1 Bit 5 Data Bit 4 Data Bit 3 LSB Data Bit 2 Data Bit 1 Data Bit 0 Figure 44. Brightness SUB Register Description Table 4. ILED vs. Brightness Register Data BMAIN or BSUB Brightness Data % of ILED_MAX BMAIN or BSUB Brightness Data 00000 0.000% 10000 8.750% 00001 0.125% 10001 10.000% 00010 0.625% 10010 12.500% 00011 1.000% 10011 15.000% 00100 1.125% 10100 16.875% 00101 1.313% 10101 18.750% 00110 1.688% 10110 22.500% 00111 2.063% 10111 26.250% 01000 2.438% 11000 31.250% 01001 2.813% 11001 37.500% 01010 3.125% 11010 43.750% 01011 3.750% 11011 52.500% 01100 4.375% 11100 61.250% 01101 5.250% 11101 70.000% 01110 6.250% 11110 87.500% 01111 7.500% 11111 100.000% 18 Submit Documentation Feedback % of ILED_MAX Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 LED Current (% of ILED_MAX) 120% 100% 80% tSTEP* 60% 40% 20% * tSTEP is the time between LED current steps programmed via bits RMP0, RMP1 31 29 27 25 23 21 19 17 15 13 11 9 7 5 3 1 0% BMAIN or BSUB Code (Decimal) Figure 45. IMAIN or ISUB vs BMAIN or BSUB Data Brightness Rate of Change Description RMP0 and RMP1 control the rate of change of the LED current IMAIN and ISUB/FB in response to changes in BMAIN and /or BSUB. There are 4 user programmable LED current rates of change settings for the LM3509 (see Table 5). Table 5. Rate of Change Bits RMP0 RMP1 Change Rate (tSTEP) 0 0 51µs/step 0 1 13ms/step 1 0 26ms/step 1 1 52ms/step For example, if RSET = 12kΩ then ILED_MAX = 20mA. With the contents of BMAIN set to 0x1F (IMAIN = 20mA), suppose the contents of BMAIN are changed to 0x00 resulting in (IMAIN = 0mA). With RMP0 =1 and RMP1 = 1 (52ms/step), IMAIN will change from 20mA to 0mA in 31 steps with 52ms elapsing between steps, excluding the step from 0x1F to 0x1E, resulting in a full scale current change in 1560ms. The total time to transition from one brightness code to another is: ttransition = (|InitialCode FinalCode| 1) u tSTEP (3) The following 3 additional examples detail possible scenarios when using the brightness register in conjunction with the rate of change bits and the enable bits. Example 1: Step 1: Write to BMAIN a value corresponding to IMAIN = 20mA. Step 2: Write 1 to ENM (turning on MAIN) Step 3: IMAIN ramps to 20mA with a rate set by RMP0 and RMP1. (RMP0 and RMP1 bits set the duration spent at one brightness code before incrementing to the next). Step 4: ENM is set to 0 before 20mA is reached, thus the LED current fades off at a rate given by RMP0 and RMP1 without IMAIN going up to 20mA. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 19 LM3509 SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 www.ti.com Example 2: Step 1: ENM is 1, and BMAIN has been programmed with code 0x01. This results in a small current into MAIN. Step 2: BMAIN is programmed with 0x1F (full scale current). This causes IMAIN to ramp toward full-scale at the rate selected by RMP0 and RMP1. Step 3: Before IMAIN reaches full-scale BMAIN is programmed with 0x09. IMAIN will continue to ramp to full scale. Step 4: When IMAIN has reached full-scale value it will ramp down to the current corresponding to 0x09 at a rate set by RMP0 and RMP1. Example 3: Step 1: Write to BMAIN a value corresponding to IMAIN = 20mA. Step 2: Write a 1 to both RMP0 and RMP1. Step 3: Write 1 to ENM (turning on MAIN). Step 4: IMAIN ramps toward 20mA with a rate set by RMP0 and RMP1. (RMP0 and RMP1 bits set the duration spent at one brightness code before incrementing to the next). Step 5: After 1.04s IMAIN has ramped to 16.875% of ILED_MAX (0.16875 × 20mA = 3.375mA). Simultaneously, RMP0 and RMP1 are both programmed with 0. Step 6: IMAIN continues ramping from 3.375mA to 20mA, but at a new ramp rate of 51µs/step. Table 6. GPIO Register Function Bits 7 – 3 Data (Bit 2) Mode (Bit 1) Enable GPIO (Bit 0) Function X X X 0 RESET/GPIO is configured as an active low reset input. This is the default power on state. X Logic Input 0 1 RESET/GPIO is configured as a logic input. The logic level applied to RESET/GPIO can be read via bit 2 of the GPIO register. X Logic Output 1 1 RESET/GPIO is configured as a logic output. A 0 in bit 2 forces RESET/GPIO low. A 1 in bit 2 forces RESET/GPIO high impedance. GPIO Register Register Address 0x80 MSB 1 Bit 7 1 Bit 6 1 Bit 5 1 Bit 4 1 Bit 3 LSB Data Bit 2 Mode Bit 1 Enable GPIO Bit 0 Figure 46. GPIO Register Description Shutdown and Output Isolation The LM3509 provides a true shutdown for either MAIN or SUB/FB when configured as a White LED bias supply. Write a 0 to ENM (bit 1) of the General Purpose register to turn off the MAIN current sink and force MAIN high impedance. Write a 0 to ENS (bit 2) of the General Purpose register to turn off the SUB/FB current sink and force SUB/FB high impedance. Writing a 1 to ENM or ENS turns on the MAIN and SUB/FB current sinks respectively. When in shutdown the leakage current into MAIN or SUB/FB is typically 3.6µA. See Typical Performance Characteristics Plots for start-up responses of the LM3509 using the ENM and ENS bits in White LED and OLED modes. Application Information LED Current Setting/Maximum LED Current Connect a resistor (RSET) from SET to GND to program the maximum LED current (ILED_MAX) into MAIN or SUB/FB. The RSET to ILED_MAX relationship is: 20 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 ILED_MAX = 192 u 1.244V RSET (4) where SET provides the constant 1.244V output. Output Voltage Setting (OLED Mode) Connect Feedback resistors from the converters output to SUB/FB to GND to set the output voltage in OLED mode (see R1 and R2 in the Typical Application Circuits (OLED Panel Power Supply). First select R2 < 100kΩ then calculate R1 such that: · §V R1 = R 2 ¨ OUT - 1¸ 1.21V © ¹ (5) In OLED mode the MAIN current sink continues to regulate the current through MAIN, however, VMAIN is no longer regulated. To avoid dropout and ensure proper current regulation the application must ensure that VMAIN > 0.3V. Input Capacitor Selection Choosing the correct size and type of input capacitor helps minimize the input voltage ripple caused by the switching of the LM3509’s boost converter. For continuous inductor current operation the input voltage ripple is composed of 2 primary components, the capacitor discharge (delta VQ) and the capacitor’s equivalent series resistance (delta VESR). These ripple components are found by: 'VQ = 'I L x D 2 x f SW x C IN and 'VESR = 2 x 'I L x R ESR where 'I L = VIN x (VOUT - VIN ) 2 x f SW x L x VOUT (6) In the typical application circuit a 1µF ceramic input capacitor works well. Since the ESR in ceramic capacitors is typically less than 5mΩ and the capacitance value is usually small, the input voltage ripple is primarily due to the capacitive discharge. With larger value capacitors such as tantalum or aluminum electrolytic the ESR can be greater than 0.5Ω. In this case the input ripple will primarily be due to the ESR. Output Capacitor Selection The LM3509’s output capacitor supplies the LED current during the boost converters on time. When the switch turns off the inductor energy is discharged through the diode supplying power to the LED’s and restoring charge to the output capacitor. This causes a sag in the output voltage during the on time and a rise in the output voltage during the off time. The output capacitor is therefore chosen to limit the output ripple to an acceptable level depending on LED or OLED panel current requirements and input/output voltage differentials. For proper operation ceramic output capacitors ranging from 1µF to 2.2µF are required. As with the input capacitor, the output voltage ripple is composed of two parts, the ripple due to capacitor discharge (delta VQ) and the ripple due to the capacitors ESR (delta VESR). For continuous conduction mode, the ripple components are found by: Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 21 LM3509 SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 'VQ = ILED u (VOUT VIN) and fSW u VOUT u COUT 'VESR = RESR u where www.ti.com § ILED u VOUT · + 'IL¸ ¨ VIN © ¹ 'IL = VIN u (VOUT VIN) 2 u fSW u L u VOUT (7) Table 7 lists different manufacturers for various capacitors and their case sizes that are suitable for use with the LM3509. When configured as a dual output LED driver a 1µF output capacitor is adequate. In OLED mode for output voltages above 12V a 2.2µF output capacitor is required. Table 7. Recommended Output Capacitors Manufacturer Part Number Value Case Size Voltage Rating TDK C1608X5R1E105M 1µF 0603 25V Murata GRM39X5R105K25D539 1µF 0603 25V TDK C2012X5R1E225M 2.2µF 0805 25V Murata GRM219R61E225KA12 2.2µF 0805 25V Inductor Selection The LM3509 is designed for use with a 10µH inductor, however 22µH are suitable providing the output capacitor is increased 2×'s. When selecting the inductor ensure that the saturation current rating (ISAT) for the chosen inductor is high enough and the inductor is large enough such that at the maximum LED current the peak inductor current is less than the LM3509’s peak switch current limit. This is done by choosing: ISAT > 'IL = I LED VOUT + 'I L × K VIN VIN x (VOUT - VIN ) 2 x f SW x L x VOUT where , and VIN x (VOUT - VIN) L> § 2 x f SW x VOUT x ¨ ¨I PEAK - I LED _ MAX x VOUT · © K x VIN ¸¸ ¹ (8) Values for IPEAK can be found in the plot of peak current limit vs. VIN in the Typical Performance Characteristics graphs. Table 8 shows possible inductors, as well as their corresponding case size and their saturation current ratings. Table 8. Recommended Inductors 22 Manufacturer Part Number Value Dimensions ISAT DC Resistance TDK VLF3012AT100MR49 10µH 2.6mm×2.8mm×1m m 490mA 0.36Ω TDK VLF4012AT100MR79 10µH 3.5mm×3.7mm×1.2 mm 800mA 0.3Ω TOKO A997AS-100M 10µH 3.8mm×3.8mm×1.8 mm 580mA 0.18Ω Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 Diode Selection The output diode must have a reverse breakdown voltage greater than the maximum output voltage. The diodes average current rating should be high enough to handle the LM3509’s output current. Additionally, the diodes peak current rating must be high enough to handle the peak inductor current. Schottky diodes are recommended due to their lower forward voltage drop (0.3V to 0.5V) compared to (0.6V to 0.8V) for PN junction diodes. If a PN junction diode is used, ensure it is the ultra-fast type (trr < 50ns) to prevent excessive loss in the rectifier. For Schottky diodes the B05030WS (or equivalent) work well for most designs. See Table 9 for a list of other Schottky Diodes with similar performance. Table 9. Recommended Schottky Diodes Manufacturer Part Number Package Reverse Breakdown Voltage Average Current Rating Diodes Inc. B05030WS SOD-323 30V 0.5A Philips BAT760 SOD-323 23V 1A ON Semiconductor NSR0320MW2T SOD-323 30V 1A Output Current Range (OLED Mode) The maximum output current the LM3509 can deliver in OLED mode is limited by 4 factors (assuming continuous conduction); the peak current limit of 770mA (typical), the inductor value, the input voltage, and the output voltage. Calculate the maximum output current (IOUT_MAX) using the following equation: (IPEAK IOUT_MAX = where 'IL = 'IL) u K u VIN VOUT VIN u (VOUT VIN) 2 u fSW u L u VOUT (9) For the typical application circuit with VOUT = 18V and assuming 70% efficiency, the maximum output current at VIN = 2.7V will be approximately 70mA. At 4.2V due to the shorter on times and lower average input currents the maximum output current (at 70% efficiency) jumps to approximately 105mA. Figure 47 shows a plot of IOUT_MAX vs. VIN using the above equation, assuming 80% efficiency. In reality factors such as current limit and efficiency will vary over VIN, temperature, and component selection. This can cause the actual IOUT_MAX to be higher or lower. Figure 47. Typical Maximum Output Current in OLED Mode Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 23 LM3509 SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 www.ti.com Output Voltage Range (OLED Mode) The LM3509's output voltage is constrained by 2 factors. On the low end it is limited by the minimum duty cycle of 10% (assuming continuous conduction) and on the high end it is limited by the over voltage protection threshold (VOVP) of 22V (typical). In order to maintain stability when operating at different output voltages the output capacitor and inductor must be changed. Refer to Table 10 for different VOUT, COUT, and L combinations. Table 10. Component Values for Output Voltage Selection VOUT COUT L VIN Range 18V 2.2µF 10µH 2.7V to 5.5V 15V 2.2µF 10µH 2.7V to 5.5V 12V 4.7µF 10µH 2.7V to 5.5V 9V 10µF 10µH 2.7V to 5.5V 7V 10µF 4.7µH 2.7V to 5.5V 5V 22µF 4.7µH 2.7V to 4.5V Layout Considerations The WSON is a leadless package with very good thermal properties. This package has an exposed DAP (die attach pad) at the underside center of the package measuring 1.6mm x 2.0mm. The main advantage of this exposed DAP is to offer low thermal resistance when soldered to the thermal ground pad on the PCB. For good PCB layout a 1:1 ratio between the package and the PCB thermal land is recommended. To further enhance thermal conductivity, the PCB thermal ground pad may include vias to a 2nd layer ground plane. For more detailed instructions on mounting WSON packages, please refer to Texas Instrument Application Note AN-1187 (Literature Number SNOA401). The high switching frequencies and large peak currents make the PCB layout a critical part of the design. The proceeding steps must be followed to ensure stable operation and proper current source regulation. 1. Divide ground into two planes, one for the return terminals of COUT, CIN and the I2C Bus, the other for the return terminals of RSET and the feedback network. Connect both planes to the exposed PAD, but nowhere else. 2. Connect the inductor and the anode of D1 as close together as possible and place this connection as close as possible to the SW pin. This reduces the inductance and resistance of the switching node which minimizes ringing and excess voltage drops. This will improve efficiency and decrease noise that can get injected into the current sources. 3. Connect the return terminals of the input capacitor and the output capacitor as close as possible to the exposed PAD and through low impedance traces. 4. Bypass IN with at least a 1µF ceramic capacitor. Connect the positive terminal of this capacitor as close as possible to IN. 5. Connect COUT as close as possible to the cathode of D1. This reduces the inductance and resistance of the output bypass node which minimizes ringing and the excess voltage drops. This will improving efficiency and decrease noise that can get injected into the current sources. 6. Route the traces for RSET and the feedback divider away from the SW node to minimize noise injection. 7. Do not connect any external capacitance to the SET pin. 24 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 LM3509 www.ti.com SNVS495D – FEBRUARY 2007 – REVISED MAY 2013 REVISION HISTORY Changes from Revision C (May 2013) to Revision D • Page Changed layout of National Data Sheet to TI format .......................................................................................................... 24 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM3509 25 PACKAGE OPTION ADDENDUM www.ti.com 2-May-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish (2) MSL Peak Temp Op Temp (°C) Top-Side Markings (3) (4) LM3509SD/NOPB ACTIVE WSON DSC 10 1000 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 85 L3509 LM3509SDE/NOPB ACTIVE WSON DSC 10 250 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 85 L3509 LM3509SDX/NOPB ACTIVE WSON DSC 10 4500 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 85 L3509 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) Multiple Top-Side Markings will be inside parentheses. Only one Top-Side Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Top-Side Marking for that device. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 1 Samples PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing LM3509SD/NOPB WSON DSC 10 LM3509SDE/NOPB WSON DSC LM3509SDX/NOPB WSON DSC SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 1000 178.0 12.4 3.3 3.3 1.0 8.0 12.0 Q1 10 250 178.0 12.4 3.3 3.3 1.0 8.0 12.0 Q1 10 4500 330.0 12.4 3.3 3.3 1.0 8.0 12.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM3509SD/NOPB WSON DSC 10 1000 213.0 191.0 55.0 LM3509SDE/NOPB WSON DSC 10 250 213.0 191.0 55.0 LM3509SDX/NOPB WSON DSC 10 4500 367.0 367.0 35.0 Pack Materials-Page 2 MECHANICAL DATA DSC0010A SDA10A (Rev A) www.ti.com IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily performed. TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and applications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provide adequate design and operating safeguards. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right relating to any combination, machine, or process in which TI components or services are used. Information published by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional restrictions. Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or service voids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements concerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or support that may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which anticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might cause harm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the use of any TI components in safety-critical applications. In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is to help enable customers to design and create their own end-product solutions that meet applicable functional safety standards and requirements. Nonetheless, such components are subject to these terms. No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties have executed a special agreement specifically governing such use. Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use in military/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI components which have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal and regulatory requirements in connection with such use. TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use of non-designated products, TI will not be responsible for any failure to meet ISO/TS16949. Products Applications Audio www.ti.com/audio Automotive and Transportation www.ti.com/automotive Amplifiers amplifier.ti.com Communications and Telecom www.ti.com/communications Data Converters dataconverter.ti.com Computers and Peripherals www.ti.com/computers DLP® Products www.dlp.com Consumer Electronics www.ti.com/consumer-apps DSP dsp.ti.com Energy and Lighting www.ti.com/energy Clocks and Timers www.ti.com/clocks Industrial www.ti.com/industrial Interface interface.ti.com Medical www.ti.com/medical Logic logic.ti.com Security www.ti.com/security Power Mgmt power.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense Microcontrollers microcontroller.ti.com Video and Imaging www.ti.com/video RFID www.ti-rfid.com OMAP Applications Processors www.ti.com/omap TI E2E Community e2e.ti.com Wireless Connectivity www.ti.com/wirelessconnectivity Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265 Copyright © 2013, Texas Instruments Incorporated