LBRX

LT3466-1 LINER

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Technical content

Figure 1. Li-Ion Powered Driver for 6 White LEDs and OLED Display small footprint (3mm × 3mm × 0.75mm) DFN package. input supply range allows operation from 2.7V to 24V.

6 LEDs

34661 F01a

34661 F01b

, LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.

PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Operating Voltage 2.7 V Maximum Operating Voltage 22 V FB1 Voltage ● 192 200 208 mV FB2 Voltage ● 788 800 812 mV FB1 Pin Bias Current V FB1 = 0.2V (Note 3) 10 50 nA FB2 Pin Bias Current V FB2 = 0.8V (Note 3) 10 50 nA Quiescent Current V FB1 = VFB2 = 1V 5 7.5 mA CTRL1 = CTRL2 = 0V 16 25 µA Switching Frequency R T = 48.7k 0.75 1 1.25 MHz Oscillator Frequency Range (Note 4) 200 2000 kHz Nominal RT Pin Voltage R T = 48.7k 0.54 V Maximum Duty Cycle R T = 48.7k ● 90 96 % RT = 20.5k 92 % RT = 267k 99 % Converter 1 Current Limit ● 310 400 mA Converter 2 Current Limit ● 310 400 mA Converter 1 VCESAT ISW1 = 300mA 320 mV Converter 2 VCESAT ISW2 = 300mA 320 mV Switch 1 Leakage Current V SW1 = 10V 0.01 5 µA Switch 2 Leakage Current V SW2 = 10V 0.01 5 µA CTRL1 Voltage for Full LED Current ● 1.8 V CTRL2 Voltage for Full Feedback Voltage ● 1V CTRL1 or CTRL2 Voltage to Turn On the IC 150 mV CTRL1 and CTRL2 Voltages to Shut Down Chip 70 mV CTRL1 Pin Bias Current V CTRL1 = 1V ● 6 9 12.5 µA CTRL2 Pin Bias Current V CTRL2 = 1V (Note 3) ● 10 120 nA (Note 1) Operating Temperature Range (Note 2) ... –40°C to 85°C ABSOLUTE AXI U RATI GSW WW U PACKAGE/ORDER I FOR ATIOUU W TJMAX = 125°C, θJA = 43°C/W, θJC = 3°C/W EXPOSED PAD (PIN 11) IS GND MUST BE SOLDERED TO PCB ORDER PART NUMBER DD PART MARKING LBRX LT3466EDD-1 Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The ● denotes specifications that apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 3V, VCTRL1 = 3V, VCTRL2 = 3V, unless otherwise specified. TOP VIEW DD PACKAGE 10-LEAD (3mm × 3mm) PLASTIC DFN

1 FB1

R T CTRL2 FB2 V OUT1 SW1 VIN SW2 VOUT2 Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/

PARAMETER CONDITIONS MIN TYP MAX UNITS VOUT1 Overvoltage Threshold 39.5 V VOUT2 Overvoltage Threshold 39.5 V Schottky 1 Forward Drop I SCHOTTKY1 = 300mA 0.85 V Schottky 2 Forward Drop I SCHOTTKY2 = 300mA 0.85 V Schottky 1 Reverse Leakage V OUT1 = 20V 5 µA Schottky 2 Reverse Leakage V OUT2 = 20V 5 µA Soft-Start Time (Switcher 1) 600 µs Soft-Start Time (Switcher 2) 600 µs ELECTRICAL CHARACTERISTICS The ● denotes specifications that apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 3V, VCTRL1 = 3V, VCTRL2 = 3V, unless otherwise specified. Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LTC3466-1E is guaranteed to meet specified performance from 0°C to 70°C. Specifications over the –40°C to 85°C operating range are assured by design, characterization and correlation with statistical process controls. Note 3: Current flows out of the pin. Note 4: Guaranteed by design and test correlation, not production tested. TYPICAL PERFOR A CE CHARACTERISTICS UW Switching Waveforms (LED Driver) Switching Waveforms (Boost Converter) V FB1 vs VCTRL1 VOUT1 100mV/DIV (AC-COUPLED) VSW1 20V/DIV IL1 100mA/DIV VIN = 3.6V 0.5 µs/DIV 34661 G01

6 LEDs AT 20mA

(AC-COUPLED) VSW2 20V/DIV IL2 100mA/DIV VIN = 3.6V 0.5 µs/DIV 34661 G02 VOUT2 = 16V/30mA CIRCUIT OF FIGURE 1 VCTRL1 (V) VFB1 (mV) 100 150

34661 G03

0.5 1 1.5 250 200 VIN = 3.6V VCTRL2 (V) VFB2 (mV) 400 600

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0.5 1 1.5 900 800 700 VIN = 3.6V VOUT2 = 16V TA = 25°C unless otherwise specified

TYPICAL PERFOR A CE CHARACTERISTICS UW Quiescent Current (CTRL1 = CTRL2 = 3V)Switch Current Limit vs Duty Cycle Shutdown Current (CTRL1 = CTRL2 = 0V) Open-Circuit Output Clamp Voltage R T vs Oscillator Frequency DUTY CYCLE (%) CURRENT LIMIT (mA) 300 400

34661 G05

TA = –50°C TA = 85°C TA = 25°C Open-Circuit Output Clamp Voltage Input Current with Output 1 and Output 2 Open Circuit OSCILLATOR FREQUENCY (kHz) RT (kΩ) 1000

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Oscillator Frequency vs VIN TA = 25°C unless otherwise specified VIN (V)

6 UVLO

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QUIESCENT CURRENT (mA) VIN (V) SHUTDOWN CURRENT (µA) 4 12 16

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TA = –50°C TA = 25°C TA = 100°C VIN (V)

38.00 OUTPUT CLAMP VOLTAGE (V)

39.00 40.00 41.00 38.50 39.50 40.50 6 1 01 41 8

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RT = 63.4k TEMPERATURE (°C) –50 –25 OUTPUT CLAMP VOLTAGE (V) 0 50 75

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RT = 63.4k VIN (V) INPUT CURRENT (mA)

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RT = 63.4k VIN (V) 800 OSCILLATOR FREQUENCY (kHz) 900 1000 1100 81 2 1 6 2 0

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RT = 48.7k

TEMPERATURE (°C) –50

0.780 FB2 VOLTAGE (V)

0.785 0.790 0.795 0.800 0.810 –25 02 5 5 0

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0.805 VIN = 3V VOUT2 = 16V/30mA SCHOTTKY FORWARD DROP (mV) SCHOTTKY FORWARD CURRENT (mA) 150 200 250 600 1000

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TEMPERATURE (°C) –50 SCHOTTKY LEAKAGE CURRENT (µA) –25 0 25 50

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VR = 36V VR = 20V Schottky Forward Voltage Drop Schottky Leakage Current CTRL Voltages to Shut Down the IC TEMPERATURE (°C) –50 CTRL VOLTAGE (mV) 100 150 –25 02 5 5 0

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VIN = 3.6V Oscillator Frequency vs Temperature TEMPERATURE (°C) –50

800 OSCILLATOR FREQUENCY (kHz)

–25 0 25 50

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VIN = 3.6V RT = 48.7k FB2 Pin Voltage vs Temperature FB2 Pin Load Regulation LOAD CURRENT (mA) –1.00 ∆VOUT2/VOUT2 (%) –0.80 –0.60 –0.40 –0.20 VIN = 3V VOUT2 = 16V 10 20

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TYPICAL PERFOR A CE CHARACTERISTICS UW TA = 25°C unless otherwise specified

VOUT1 (Pin 1): Output of Converter 1. This pin is connected to the cathode of the internal Schottky diode. Connect an output capacitor from this pin to ground. SW1 (Pin 2): Switch Pin for Converter 1. Connect the inductor at this pin. VIN (Pin 3): Input Supply Pin. Must be locally bypassed with a 1µF, X5R or X7R type ceramic capacitor. SW2 (Pin 4): Switch Pin for Converter 2. Connect the inductor at this pin. VOUT2 (Pin 5): Output of Converter 2. This pin is connected to the cathode of the internal Schottky diode. Connect an output capacitor from this pin to ground. FB2 (Pin 6): Feedback Pin for Converter 2. The nominal voltage at this pin is 800mV. Connect the resistor divider to this pin. The feedback voltage can be programmed as: VFB2 ≈ VCTRL2, when VCTRL2 < 0.8V VFB2 = 0.8V, when VCTRL2 > 1V CTRL2 (Pin 7): Dimming and Shutdown Pin for Con- verter 2. As the pin voltage is ramped from 0V to 1V, the FB2 pin voltage tracks the CTRL2 voltage and ramps up to 0.8V. Any voltage above 1V does not affect the feedback voltage. Do not leave the pin floating. It must be connected to ground to disable converter 2. R T (Pin 8): Timing Resistor to Program the Switching Frequency. The switching frequency can be programmed from 200KHz to 2MHz. CTRL1 (Pin 9): Dimming and Shutdown Pin for Con- verter 1. Connect this pin to ground to disable the con- verter. As the pin voltage is ramped from 0V to 1.8V, the LED current ramps from 0 to ILED1 (= 200mV/RFB1). Any voltage above 1.8V does not affect the LED current. FB1 (Pin 10): Feedback Pin for Converter 1. The nominal voltage at this pin is 200mV. Connect cathode of the lowest LED and the feedback resistor at this pin. The LED current can be programmed by : I LED1 ≈ (VCTRL1/5 • RFB1), when VCTRL1 < 1V ILED1 ≈ (200mV/RFB1), when VCTRL1 > 1.8V Exposed Pad (Pin 11): The Exposed Pad must be soldered to the PCB system ground.

34661 F02

Figure 2. Block Diagram

In the event one of the converters has an output open-circuit, its output voltage will be clamped at 39.5V. However, the other converter will continue functioning properly. The photo in Figure 4b shows circuit operation with converter 1 output open-circuit and converter 2 driving the OLED display. Con- verter 1 starts switching at a lower inductor current and begins skipping pulses, thereby reducing its input current. Converter 2 continues functioning properly. Soft-Start The LT3466-1 has a separate internal soft-start circuitry for each converter. Soft-start helps to limit the inrush current during start-up. Soft-start is achieved by clamping the output of the error amplifier during the soft-start period. This limits the peak inductor current and ramps up the output voltage in a controlled manner. The converter enters into soft-start mode whenever the respective CTRL pin is pulled from low to high. Figure 5 shows the start-up waveforms with converter 1 driving six LEDs at 20mA. The filtered input current, as shown in Figure 5, is well controlled. The soft-start circuitry is less effective when driving a higher number of LEDs. Undervoltage Lockout The LT3466-1 has an undervoltage lockout circuit which shuts down both converters when the input voltage drops below 2.1V (typ). This prevents the converter from switch- ing in an erratic mode when powered from low supply voltages. OPERATIOU Figure 4a. Transient Response of Switcher 1 with LED1 Disconnected from the Output Figure 4b. Output 1 Open-Circuit Waveforms Figure 5. Start-Up Waveforms VOUT1 10V/DIV 200µs/DIV LED1 DISCONNECTED AT THIS POINT VIN = 3.3V CIRCUIT OF FIGURE 1

34661 F04a

200µs/DIVVIN = 3.6V

6 LEDs, 20mA

34661 F05

1µs/DIVVIN = 3.6V CIRCUIT OF FIGURE 1

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switching losses and decreased efficiency. different RT values is shown in Figure 7. albeit at the cost of increased switching losses. Figure 6. Timing Resistor (RT) Value Figure 7. Efficiency Comparison for Different RT Resistors

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34661 F07

frequency is shown in the Figure 6.

Recommended inductor values range from 10µH to 68µH. information and for their entire selection of related parts. Table 1. Recommended Inductors tions. Always use a capacitor with sufficient voltage rating. on their entire selection of ceramic parts. Table 2. Ceramic Capacitor Manufacturers the peak of the inrush current to be below 1A. Table 3. Inrush Peak Current

ing in a lower peak inrush current. FB1 (Figure 1). The feedback reference is 200mV. are preferred (1% is recommended). Table 4. RFB1 Value Selection control is a variable DC voltage to adjust the LED current. beyond 1.8V, it has no effect on the LED current. in the Typical Performance Characteristics graphs. (Figure 8) by an RC network and fed to the CTRL1 pin.

34661 F08

Figure 8. Dimming Control Using a Filtered PWM Signal The LT3466-1 regulates the voltage at the FB2 pin to 0.8V. network maximizing efficiency.

in a linear change in the boost output voltage (VOUT2). Connect the CTRL2 pin to ground to disable converter 2. Figure 10. Li-Ion Powered Driver for 6 White LEDs and a

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Figure 9. VFB2 vs VCTRL2 (Channel 1) and an OLED display or, LCD bias (Channel 2). reduce the current drained from the battery in shutdown. PNP transistor, Q1, as shown in Figure 10. Philips BC807 (Q1) to provide isolation.

34661 F09

Figure 11. Recommended Component Placement paid to the PCB board layout and component placement. back pins (FB1 and FB2) away from the switching nodes.

33µH 1µF COUT1 1µF COUT2 1µF 33µH LT3466-1 SHUTDOWN AND DIMMING CONTROL 2 C IN: TAIYO YUDEN JMK107BJ105 COUT1, COUT2: TAIYO YUDEN GMK316BJ105 L1, L2: 33µH TOKO D52LC SHUTDOWN AND DIMMING CONTROL 1 VOUT1 FB1 RFB1 10Ω 24.9k 475k34661 TA02a VOUT2 FB2 63.4k OUTPUT CURRENT (mA) EFFICIENCY (%) 302520

34661 TA02b

VIN = 3.6V VOUT2 = 16V Li-Ion Powered Driver for 6 White LEDs and OLED Display Conversion Efficiency CTRL1 CTRL2RT SW1 SW2VIN 3V TO 5V 12V 30mA AT V IN = 3V 60mA AT VIN = 5V 15µH C IN 1µF COUT1 0.47µF COUT2 1µF 38.3k 15µH LT3466-1 C IN: TAIYO YUDEN JMK107BJ105 COUT1: TAIYO YUDEN EMK212BJ474 COUT2: TAIYO YUDEN EMK212BJ105 L1, L2: MURATA LQH32CN150K53 VOUT1 FB1 RFB1 10Ω 64.9k 909k

34661 TA01a

4 LEDs

Li-Ion Powered 4 White LEDs Driver and 12V Boost Converter Efficiency vs Load Current LOAD CURRENT (mA) EFFICIENCY (%) 10 20 30 40

34661 TA01b

85 VIN = 5V

VIN = 3V

4 LEDs/20mA

VOUT2 = 12V

Li-Ion Powered Driver for 6 White LEDs and OLED with Output Disconnect Conversion Efficiency LOAD CURRENT (mA) EFFICIENCY (%) 5 10 15 20

34661 TA03b

VIN = 3.6V VOUT2 = 16V CTRL1 CTRL2RT SW1 SW2VIN 3V TO 5V 33µH CIN 1µF COUT1 1µF COUT2 0.47µF 63.4k 33µH LT3466-1 C IN: TAIYO YUDEN JMK107BJ105 COUT1: TAIYO YUDEN GMK316BJ105 COUT2, COUT3: TAIYO YUDEN TMK316BJ474 L1, L2: 33µH TOKO D52LC Q1: PHILIPS BC807 VOUT1 FB1 RFB1 10Ω 24.9k 14k

34661 TA03a

0.47µF6 LEDs VOUT2 20V/DIV 2ms/DIVVIN = 3.6V VOUT2 = 16V

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Li-Ion Powered Driver for 6 White LEDs and OLED with Output Disconnect Conversion Efficiency CTRL1 CTRL2RT SW1 SW2VIN 3V TO 5V 33µH CIN 1µF COUT1 1µF COUT2 0.47µF 63.4k 33µH LT3466-1 C IN: TAIYO YUDEN JMK107BJ105 COUT1: TAIYO YUDEN GMK316BJ105 COUT2, COUT3: TAIYO YUDEN TMK316BJ474 L1, L2: 33µH TOKO D52LC Q1: SILICONIX TPO610 NOTE: ENSURE THAT VOUT2 > VIN(MAX) + 5V VOUT1 FB1 RFB1 10Ω 24.9k

34661 TA04a

0.47µF6 LEDs LOAD CURRENT (mA) EFFICIENCY (%)65 15 25

34661 TA04b

VIN = 3.6V VOUT2 = 16V VOUT2 20V/DIV 2ms/DIVVIN = 3.6V VOUT2 = 16V

34661 TA04c

Li-Ion to 10 White LEDs and LCD Bias (±8V) with Output Disconnect Conversion Efficiency CTRL1 CTRL2RT SW1 SW2VIN 3V TO 5V –8V 10mA 10mA 33µH C IN 1µF COUT1 1µF 147k CIN: TAIYO YUDEN JMK107BJ105 COUT1: TAIYO YUDEN UMK325BJ105 COUT2, COUT3: TAIYO YUDEN GMK316BJ105 C1, C2: TAIYO YUDEN UMK212BJ104 D1, D2: PHILIPS BAT54S L1: 68µH TOKO D52LC L2: 33µF TOKO D52LC 68µH

10 LEDs

V OUT1 FB1 RFB1 16.5Ω

34661 TA05a

1µF COUT3 1µF 909k 10k 0.1µF D1 0.1µF LED CURRENT (mA) EFFICIENCY (%) 2 468

34661 TA05b

VIN = 3.6V +8V/10mA –8V/10mA +8V OUTPUT 10V/DIV –8V OUTPUT 10V/DIV 2ms/DIVVIN = 3.6V +8V/10mA –8V/10mA

34661 TA05c

10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699) 3.00 ±0.10 (4 SIDES) NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2). CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 0.38 ± 0.10 BOTTOM VIEW—EXPOSED PAD 1.65 ± 0.10 (2 SIDES) 0.75 ±0.05 R = 0.115 TYP 2.38 ±0.10 (2 SIDES) 106 PIN 1 TOP MARK (SEE NOTE 6)

0.200 REF

0.00 – 0.05 (DD10) DFN 1103 0.25 ± 0.05 2.38 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 1.65 ±0.05 (2 SIDES)2.15 ±0.05 0.50 BSC 0.675 ±0.05 3.50 ±0.05 PACKAGE OUTLINE 0.25 ± 0.05

0.50 BSC

Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

LT/TP 0705 500 • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 2005 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com TYPICAL APPLICATIO U Li-Ion to 8 White LEDs and ±15V TFT LCD Bias Supply Conversion Efficiency PART NUMBER DESCRIPTION COMMENTS LT1618 Constant Current, Constant Voltage 1.4MHz, High Efficiency V IN: 1.6V to 18V, VOUT(MAX) = 34V, IQ = 1.8mA, ISD < 1µA, Boost Regulator MS/EDD Packages LT1932 Constant Current, 1.2MHz, High Efficiency White LED Boost V IN: 1V to 10V, VOUT(MAX) = 34V, IQ = 1.2mA, ISD < 1µA, Regulator ThinSOT TM Package LT1937 Constant Current, 1.2MHz, High Efficiency White LED Boost V IN: 2.5V to 10V, VOUT(MAX) = 34V, IQ = 1.9mA, ISD < 1µA, Regulator ThinSOT, SC70 Packages LTC 3200-5 Low Noise, 2MHz, Regulated Charge Pump White LED Driver V IN: 2.7V to 4.5V, VOUT(MAX) = 5V, IQ = 8mA, ISD < 1µA, ThinSOT Package LTC3202 Low Noise, 1.5MHz, Regulated Charge Pump White LED Driver V IN: 2.7V to 4.5V, VOUT(MAX) = 5.5V, IQ = 5mA, ISD < 1µA, MS/EDD Packages LTC3205 High Efficiency, Multidisplay LED Controller V IN: 2.8V to 4.5V, VOUT(MAX) = 6V, IQ = 50µA, ISD < 1µA, LTC3216 1A Low Noise High Current LED Charge Pump with Independent V IN: 2.9V to 4.4V, VOUT(MAX) = 5.5V, IQ = 300µA, ISD < 2.5µA, Flash/Torch Current Control DFN Package LTC3453 500mA Synchronous Buck-Boost High Current LED Driver V IN: 2.7V to 5.5V, VOUT(MAX) = 5.5V, IQ = 0.6mA, ISD < 6µA, in Q FN QFN Package LT3465/LT3465A Constant Current, 1.2MHz/2.7MHz, High Efficiency White LED V IN: 2.7V to 16V, VOUT(MAX) = 34V, IQ = 1.9mA, ISD < 1µA, Boost Regulator with Integrated Schottky Diode ThinSOT Package LT3466 Dual Constant Current, 2MHz High Efficiency White LED Boost V IN: 2.7V to 24V, VOUT(MAX) = 40V, IQ = 5mA, ISD < 16µA, Regulator with Integrated Schottky Diode DFN Package LT3479 3A, Full Featured DC/DC Converter with Soft-Start and Inrush V IN: 2.5V to 24V, VOUT(MAX) = 40V, IQ = 6.5mA, ISD < 1µA, Current Protection DFN/TSSOP Packages ThinSOT is a trademark of Linear Technology Corporation. RELATED PARTS CTRL1 CTRL2RT SW1 SW2VIN 3V TO 5V –15V 10mA 15V 10mA 33µH C IN 1µF 0.1µF COUT1 1µF COUT2 1µF COUT3 1µF 33µH LT3466-1 VOUT1 FB1 RFB1 13.3Ω 26.7k 475k

34661 TA06a

63.4k

8 LEDs

CIN: TAIYO YUDEN JMK107BJ105 COUT1, COUT2, COUT3: TAIYO YUDEN GMK316BJ105 C1: TAIYO YUDEN UMK212BJ104 L1, L2: 33µH TOKO D52LC D1: PHILIPS BAT54S LED CURRENT (mA) EFFICIENCY (%) 2.5 5 7.5 10

34661 TA06b

12.5 15 VIN = 3.6V +15V/10mA –15V/10mA