LT3465/LT3465A 1.2MHz/2.4MHz White LED Drivers with Built-in Schottky in ThinSOT U FEATURES DESCRIPTIO ■ The LT®3465/LT3465A are step-up DC/DC converters designed to drive up to six LEDs in series from a Li-Ion cell. Series connection of the LEDs provides identical LED currents and eliminates the need for ballast resistors. These devices integrate the Schottky diode required externally on competing devices. Additional features include output voltage limiting when LEDs are disconnected, onepin shutdown and dimming control. The LT3465 has internal soft-start. ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Inherently Matched LED Current Drives Up to Six LEDs from a 3.6V Supply No External Schottky Diode Required 1.2MHz Switching Frequency (LT3465) 2.4MHz Switching Frequency Above AM Broadcast Band (LT3465A) VIN Range: 2.7V to 16V VOUT(MAX) = 30V Automatic Soft-Start (LT3465) Open LED Protection High Efficiency: 81% (LT3465) 79% (LT3465A) Typical Requires Only 0.22µF Output Capacitor Low Profile (1mm) SOT-23 U APPLICATIO S ■ ■ ■ ■ The LT3465 and LT3465A are available in the low profile (1mm) 6-lead SOT-23 (ThinSOTTM) package. Cellular Phones PDAs, Handheld Computers Digital Cameras MP3 Players GPS Receivers , LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. U ■ The LT3465 switches at 1.2MHz, allowing the use of tiny external components. The faster LT3465A switches at 2.4MHz. Constant frequency switching results in low input noise and a small output capacitor. Just 0.22µF is required for 3-, 4- or 5-LED applications. TYPICAL APPLICATIO Conversion Efficiency L1 22µH 82 VIN = 3.6V 80 4 LEDs 3V TO 5V 78 VOUT VIN SHUTDOWN AND DIMMING CONTROL C1 1µF LT3465/ LT3465A FB CTRL GND C1, C2: X5R OR X7R DIELECTRIC L1: MURATA LQH32CN220 C2 0.22µF 10Ω 3465A F01a EFFICIENCY (%) SW 76 74 72 70 68 66 64 60 Figure 1. Li-Ion Powered Driver for Four White LEDs LT3465 LT3465A 62 0 5 10 15 20 LED CURRENT (mA) 3465A F01b 3465afa 1 LT3465/LT3465A W W W AXI U U U W PACKAGE/ORDER I FOR ATIO U ABSOLUTE RATI GS (Note 1) TOP VIEW Input Voltage (VIN) ................................................. 16V SW Voltage ............................................................. 36V FB Voltage ................................................................ 2V CTRL Voltage .......................................................... 10V Operating Temperature Range (Note 2) .. – 40°C to 85°C Maximum Junction Temperature ......................... 125°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................. 300°C VOUT 1 6 SW GND 2 5 VIN 4 CTRL FB 3 S6 PACKAGE 6-LEAD PLASTIC TSOT-23 TJMAX = 125°C, θJA = 256°C/W IN FREE AIR θJA = 120°C ON BOARD OVER GROUND PLANE S6 PART MARKING ORDER PART NUMBER LT3465ES6 LT3465AES6 LTH2 LTAFT 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/ Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 3V, VCTRL = 3V, unless otherwise noted. PARAMETER CONDITIONS MIN Minimum Operating Voltage LT3465 TYP 2.7 LT3465A TYP 0°C ≤ TA ≤ 85°C 188 Not Switching CTRL = 0V Switching Frequency MAX UNITS V 16 FB Pin Bias Current Supply Current MIN 2.7 Maximum Operating Voltage Feedback Voltage MAX 188 16 V 200 212 mV 200 212 10 35 100 10 35 100 nA 1.9 2.0 2.6 3.2 3.3 5.0 1.9 2.0 2.6 3.2 3.3 5.0 mA µA 1.6 2.8 MHz 0.8 1.2 1.8 2.4 Maximum Duty Cycle ● 90 93 90 93 % Switch Current Limit ● 225 340 225 340 mA Switch VCESAT ISW = 250mA 300 Switch Leakage Current VSW = 5V 0.01 VCTRL for Full LED Current VCTRL to Enable Chip ● VCTRL to Shut Down Chip ● CTRL Pin Bias Current TA = 85°C TA = –40°C Soft-Start Time 300 5 0.01 mV 5 1.8 1.8 V 150 150 mV 50 48 40 60 60 50 75 72 60 90 48 40 60 60 50 75 50 mV 72 60 90 µA µA µA µs 600 Schottky Forward Drop ID = 150mA Schottky Leakage Current VR = 30V Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LT3465E/LT3465AE are guaranteed to meet performance µA 0.7 0.7 4 V 4 µA specifications from 0°C to 70°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. 3465afa 2 LT3465/LT3465A U W TYPICAL PERFOR A CE CHARACTERISTICS Switch Saturation Voltage (VCESAT) 300 400 350 300 250 200 150 100 50 0 50 100 150 200 250 SWITCH CURRENT (mA) 300 250 24 21 200 150 18 15 12 100 9 6 50 3 350 0 1000 400 600 800 200 SCHOTTKY FORWARD DROP (mV) 0 1200 4 2 6 10 8 VIN (V) 12 3465A G02 3465A G01 VFB vs VCTRL 250 TA = 25°C 27 0 0 30 TA = 25°C IQ (µA) TA = 25°C SCHOTTKY FORWARD CURRENT (mA) SWITCH SATURATION VOLTAGE (mV) 450 Shutdown Quiescent Current (CTRL = 0V) Schottky Forward Voltage Drop TA = 25°C 16 3465A G03 Open-Circuit Output Clamp Voltage Input Current in Output Open Circuit 5 35 14 TA = 25°C TA = 25°C 150 100 50 4 INPUT CURRENT (mA) 200 OUTPUT CLAMP VOLTAGE (V) FEEDBACK VOLTAGE (mV) 30 25 20 15 10 3 2 1 5 0 0 0 0 1 0.5 1.5 CONTROL VOLTAGE (V) 2 2 4 10 8 12 6 INPUT VOLTAGE (V) 3465A G04 14 2 16 2.5 4 3.5 3 INPUT VOLTAGE (V) 5 3465A G06 3465A G05 Switching Waveforms (LT3465) 4.5 Switching Frequency Switching Waveforms (LT3465A) VSW 10V/DIV IL 100mA/DIV IL 50mA/DIV VOUT 100mV/DIV VOUT 50mV/DIV VIN = 3.6V 4 LEDs 20mA, 22µH 200ns/DIV 3465A G07a VIN = 3.6V 4 LEDs 20mA, 22µH 100ns/DIV 3465A G07b SWITCHING FREQUENCY (MHz) 3.0 VSW 10V/DIV 2.5 LT3465A 2.0 1.5 LT3465 1.0 0.5 0 –50 50 0 TEMPERATURE (°C) 100 4365A G08 3465afa 3 LT3465/LT3465A U W TYPICAL PERFOR A CE CHARACTERISTICS Quiescent Current (CTRL = 3V) Feedback Voltage Switching Current Limit 3.0 210 400 350 204 CURRENT LIMIT (mA) 2.5 206 2.0 202 IQ (mA) FEEDBACK VOLTAGE (mV) 208 200 1.5 198 1.0 196 194 –50°C 25°C 100°C 0.5 192 190 –50 –30 –10 10 30 50 TEMPERATURE (°C) 0 90 5 10 VIN (V) 15 70 65 100 SCHOTTKY LEAKAGE CURRENT (µA) EFFICIENCY (%) 15mA 50 0 TEMPERATURE (°C) –50°C 25°C 100°C 0 20 40 60 DUTY CYCLE (%) 80 100 3465A G11 8 20mA 10mA 60 –50 100 Schottky Leakage Current 80 75 150 3465A G10 VIN = 3.6V, 4 LEDs LT3465 LT3465A 200 0 20 3465A G09 85 250 50 0 70 300 7 VR = 25 6 VR = 16 5 VR = 10 4 3 2 1 0 –50 0 50 100 TEMPERATURE (°C) 3465A G12 3465A G13 3465afa 4 LT3465/LT3465A U U U PI FU CTIO S VOUT (Pin 1): Output Pin. Connect to output capacitor and LEDs. Minimize trace between this pin and output capacitor to reduce EMI. GND (Pin 2): Ground Pin. Connect directly to local ground plane. FB (Pin 3): Feedback Pin. Reference voltage is 200mV. Connect LEDs and a resistor at this pin. LED current is determined by the resistance and CTRL pin voltage: CTRL (Pin 4): Dimming Control and Shutdown Pin. Ground this pin to shut down the device. When VCTRL is greater than about 1.8V, full-scale LED current is generated. When VCTRL is less than 1V, LED current is reduced. Floating this pin places the device in shutdown mode. VIN (Pin 5): Input Supply Pin. Must be locally bypassed with a 1µF X5R or X7R type ceramic capacitor. SW (Pin 6): Switch Pin. Connect inductor here. ⎛ ⎞⎞ ⎛ ⎛ 200mV ⎞ ⎜ ⎟⎟ ⎜ exp ⎜ ⎝ 26mV ⎟⎠ 1 ⎜ ⎜ • 200mV – 26mV • 1n ILED = + 1⎟ ⎟ for VCTRL > 150mV ⎜ RFB ⎜ ⎛ VCTRL (mV ) ⎞ ⎟ ⎟ ⎜ ⎟⎟ ⎜ expp ⎜ ⎝ 5mV • 26mV ⎟⎠ ⎠ ⎠ ⎝ ⎝ 3465afa 5 LT3465/LT3465A W BLOCK DIAGRA VIN FB 5 3 VREF 1.25V 200mV – + + 6 SW – A1 1 DRIVER RC + A2 R CC S Q1 Q OVERVOLTAGE PROTECT + Σ 0.2Ω 10k CTRL VOUT COMPARATOR – RAMP GENERATOR 40k 4 2 GND 1.2MHz* OSCILLATOR 3465A F02 *2.4MHz FOR LT3465A Figure 2. LT3465 Block Diagram 3465afa 6 LT3465/LT3465A U W U U APPLICATIO S I FOR ATIO Operation Minimum Output Current The LT3465 uses a constant frequency, current mode control scheme to provide excellent line and load regulation. Operation can be best understood by referring to the block diagram in Figure 2. At the start of each oscillator cycle, the SR latch is set, which turns on the power switch Q1. A voltage proportional to the switch current is added to a stabilizing ramp and the resulting sum is fed into the positive terminal of the PWM comparator A2. When this voltage exceeds the level at the negative input of A2, the SR latch is reset turning off the power switch. The level at the negative input of A2 is set by the error amplifier A1, and is simply an amplified version of the difference between the feedback voltage and the reference voltage of 200mV. In this manner, the error amplifier sets the correct peak current level to keep the output in regulation. If the error amplifier’s output increases, more current is delivered to the output; if it decreases, less current is delivered. The CTRL pin voltage is used to adjust the reference voltage. The block diagram for the LT3465A (not shown) is identical except that the oscillator frequency is 2.4MHz. The LT3465 can drive a 3-LED string at 1.5mA LED current without pulse skipping. As current is further reduced, the device will begin skipping pulses. This will result in some low frequency ripple, although the LED current remains regulated on an average basis down to zero. The photo in Figure 3a details circuit operation driving three white LEDs at a 1.5mA load. Peak inductor current is less than 40mA and the regulator operates in discontinuous mode, meaning the inductor current reaches zero during the discharge phase. After the inductor current reaches zero, the SW pin exhibits ringing due to the LC tank circuit formed by the inductor in combination with switch and diode capacitance. This ringing is not harmful; far less spectral energy is contained in the ringing than in the switch transitions. The ringing can be damped by application of a 300Ω resistor across the inductor, although this will degrade efficiency. Because of the higher switching frequency, the LT3465A can drive a 3-LED string at 0.2mA LED current without pulse VSW 5V/DIV IL 20mA/DIV VOUT 10mV/DIV VIN = 4.2V ILED = 1.5mA 3 LEDs 0.2µs/DIV 3465A F03a Figure 3a. Switching Waveforms (LT3465) VSW 5V/DIV IL 20mA/DIV VOUT 10mV/DIV VIN = 4.2V ILED = 0.2mA 3 LEDs 0.1µs/DIV 3465A F03b Figure 3b. Switching Waveforms (LT3465A) 3465afa 7 LT3465/LT3465A U W U U APPLICATIO S I FOR ATIO skipping using a 1k resistor from FB to GND. The photo in Figure 3b details circuit operation driving three white LEDs at a 0.2mA load. Peak inductor current is less than 30mA. 85 EFFICIENCY (%) 75 Inductor Selection A 22µH inductor is recommended for most LT3465 applications. Although small size and high efficiency are major concerns, the inductor should have low core losses at 1.2MHz and low DCR (copper wire resistance). Some inductors in this category with small size are listed in Table 1. The efficiency comparison of different inductors is shown in Figure 4a. A 22µH or 10µH inductor is recommended for most LT3465A applications. The inductor should have low core losses at 2.4MHz and low DCR. The efficiency comparison of different inductors is shown in figure 4b. LQH32CN220 LQH2MCN220 0.71 2.4 250 185 Murata 814-237-1431 www.murata.com ELJPC220KF 4.0 160 Panasonic 714-373-7334 www.panasonic.com CDRH3D16-220 LB2012B220M LEM2520-220 0.53 1.7 5.5 350 75 125 Taiyo Yuden 408-573-4150 www.t-yuden.com Taiyo Yuden 408-573-4150 www.t-yuden.com MURATA LQH32CN220 TAIYO YUDEN LB2012B220M TAIYO YUDEN CB2012B220 50 0 5 10 20 15 LED CURRENT (mA) 3465A F04b Figure 4a. Efficiency Comparison of Different Inductors (LT3465) 80 VIN = 3.6V 4 LEDs 75 MANUFACTURER Sumida 847-956-0666 www.sumida.com 65 55 EFFICIENCY (%) DCR (Ω) CURRENT RATING (mA) 70 60 Table 1. Recommended Inductors PART NUMBER VIN = 3.6V 4 LEDs 80 70 65 MURATA LQH32CN220 MURATA LQH32CN100 MURATA LQH2MCN220 TOKO D312-220 TOKO D312-100 TAIYO YUDEN LB2012B220 60 55 50 5 0 10 20 15 LED CURRENT (mA) 3465A F04b Figure 4b. Efficiency Comparison of Different Inductors (LT3465A) Capacitor Selection The small size of ceramic capacitors makes them ideal for LT3465 and LT3465A applications. X5R and X7R types are recommended because they retain their capacitance over wider voltage and temperature ranges than other types such as Y5V or Z5U. A 1µF input capacitor and a 0.22µF output capacitor are sufficient for most LT3465 and LT3465A applications. Table 2. Recommended Ceramic Capacitor Manufacturers MANUFACTURER PHONE URL Taiyo Yuden 408-573-4150 www.t-yuden.com Murata 814-237-1431 www.murata.com Kemet 408-986-0424 www.kemet.com 3465afa 8 LT3465/LT3465A U W U U APPLICATIO S I FOR ATIO Soft-Start (LT3465) The LT3465 has an internal soft-start circuit to limit the input current during circuit start-up. The circuit start-up waveforms are shown in Figure 5. inductors, which is usually the case for this application, the peak inrush current can be simplified as follows: IP = ⎛ α π⎞ VIN – 0.6 • exp⎜ – • ⎟ L•ω ⎝ ω 2⎠ Table 3 gives inrush peak currents for some component selections. IIN 50mA/DIV Table 3. Inrush Peak Current VOUT 5V/DIV VFB 100mV/DIV CTRL 5V/DIV VIN = 3.6V 4 LEDs, 20mA L = 22µH C = 0.22µF 200µs/DIV 3465 F05 Figure 5. Start-Up Waveforms The LT3465 and LT3465A have a built-in Schottky diode. When supply voltage is applied to the VIN pin, the voltage difference between VIN and VOUT generates inrush current flowing from input through the inductor and the Schottky diode to charge the output capacitor to VIN. The maximum current the Schottky diode in the LT3465 and LT3465A can sustain is 1A. The selection of inductor and capacitor value should ensure the peak of the inrush current to be below 1A. The peak inrush current can be calculated as follows: α= ω= ⎡ ⎡ α ⎛ ω⎞⎤ ⎛ ω⎞⎤ VIN – 0.6 • exp⎢ – • arctan⎜ ⎟ ⎥ • sin⎢arctan⎜ ⎟ ⎥ L•ω ⎝ α ⎠ ⎥⎦ ⎝ α ⎠ ⎥⎦ ⎢⎣ ⎢⎣ ω r + 1.5 2 •L ( r (Ω) L (µH) C (µF) IP (A) 5 0.5 22 0.22 0.38 5 0.5 22 1 0.70 3.6 0.5 22 0.22 0.26 5 0.5 33 1 0.60 LED Current and Dimming Control The LED current is controlled by the feedback resistor (R1 in Figure 1) and the feedback reference voltage. Inrush Current IP = VIN (V) ) r + 1.5 1 – L •C 4 • L2 2 where L is the inductance, r is the resistance of the inductor and C is the output capacitance. For low DCR ILED = VFB/RFB The CTRL pin controls the feedback reference voltage as shown in the Typical Performance Characteristics. For CTRL higher than 1.8V, the feedback reference is 200mV, which results in full LED current. CTRL pin can be used as dimming control when CTRL voltage is between 200mV to 1.5V. In order to have accurate LED current, precision resistors are preferred (1% is recommended). The formula and table for RFB selection are shown below. RFB = 200mV/ILED-Full (1) Table 4. RFB Resistor Value Selection FULL ILED (mA) R1 (Ω) 5 40.0 10 20.0 15 13.3 20 10.0 The filtered PWM signal can be considered to be an adjustable DC voltage. It can be used to adjust the CTRL voltage source in dimming control. The circuit is shown in Figure 6. The corner frequency of R1 and C1 should be 3465afa 9 LT3465/LT3465A U W U U APPLICATIO S I FOR ATIO percent duty cycle sets the LED current to zero, while 100% duty cycle sets it to full current. Average LED current increases proportionally with the duty cycle of the PWM signal. With the PWM signal at the CTRL pin to turn the LT3465A on and off, the output capacitor is charged and discharged accordingly. This capacitor charging/ discharging affects the waveform at the FB pin. For low PWM frequencies the output capacitor charging/discharging time is a very small portion in a PWM period. The average FB voltage increases linearly with the PWM duty cycle. As the PWM frequency increases, the capacitor charging/discharging has a larger effect on the linearity of the PWM control. Waveforms for a 1kHz and 10kHz PWM CTRL signals are shown in Figures 7a and 7b respectively. The capacitor charging/discharging has a larger effect on the FB waveform in the 10kHz case than that in the 1kHz lower than the frequency of the PWM signal. R1 needs to be much smaller than the internal impedance in the CTRL pin, which is 50kΩ. A 5k resistor is suggested. LT3465/ LT3465A R1 5k PWM C1 100nF CTRL 3465A F06 Figure 6. Dimming Control Using a Filtered PWM Signal Dimming Using Direct PWM (LT3465A) Unlike the LT3465, the LT3465A does not have internal soft-start. Although the input current is higher during start-up, the absence of soft-start allows the CTRL pin to be directly driven with a PWM signal for dimming. A zero LT3465A PWM CTRL FB 100mV/DIV CTRL 2V/DIV 200µs/DIV (1kHz) 3465A F07a Figure 7a. FB 100mV/DIV CTRL 2V/DIV 20µs/DIV (10kHz) 3465A F07b Figure 7b. 3465afa 10 LT3465/LT3465A U W U U APPLICATIO S I FOR ATIO case. The Average FB Voltage vs PWM Duty Cycle curves of different PWM frequencies with different output capacitors are shown in Figures 7c and 7d respectively. For PWM frequency lower than 1kHz, the curves are almost linear. For PWM frequency higher than 10kHz, the curves show strong nonlinearity. Since the cause of the nonlinearity is the output capacitor charging/discharging, the output capacitance and output voltage also affect 200 COUT = 0.22µF 4 LEDs 180 AVERAGE FEEDBACK VOLTAGE (mV) AVERAGE FEEDBACK VOLTAGE (mV) 200 160 140 120 100 80 10Hz 100Hz 1kHz 10kHz 30kHz 60 40 20 0 the nonlinearity in the high PWM frequencies. Because smaller capacitance corresponds to shorter capacitor charging/discharging time, the smaller output capacitance has better linearity as shown in Figures 7c and 7d. Figures 7e and 7f show the output voltage’s effect to the curves. The PWM signal should be at least 1.8V in magnitude; lower voltage will lower the feedback voltage as shown in Equation 1. 160 140 120 100 80 10Hz 100Hz 1kHz 10kHz 30kHz 60 40 20 0 20 60 80 40 CTRL PWM DUTY CYCLE (%) 0 COUT = 0.47µF 4 LEDs 180 100 0 10 20 30 40 50 60 70 80 90 100 CTRL PWM DUTY CYCLE (%) 3465A F07d 3465A F07c Figure 7c. VFB vs CTRL PWM Duty Cycle 200 10kHz PWM COUT = 0.22µF 180 160 140 120 100 80 60 2 LEDs 3 LEDs 4 LEDs 40 20 0 AVERAGE FEEDBACK VOLTAGE (mV) AVERAGE FEEDBACK VOLTAGE (mV) 200 Figure 7d. VFB vs CTRL PWM Duty Cycle 160 140 120 100 80 60 20 60 80 40 CTRL PWM DUTY CYCLE (%) 100 3465A F07e Figure 7e.VFB vs CTRL PWM Duty Cycle 2 LEDs 3 LEDs 4 LEDs 40 20 0 0 30kHz PWM COUT = 0.22µF 180 0 20 60 80 40 CTRL PWM DUTY CYCLE (%) 100 3465A F07f Figure 7f.VFB vs CTRL PWM Duty Cycle 3465afa 11 LT3465/LT3465A U W U U APPLICATIO S I FOR ATIO Open-Circuit Protection The LT3465 and LT3465A have an internal open-circuit protection circuit. In the cases of output open circuit, when the LEDs are disconnected from the circuit or the LEDs fail, the VOUT is clamped at 30V. The LT3465 and LT3465A will then switch at a very low frequency to minimize the input current. VOUT and input current during output open circuit are shown in the Typical Performance Characteristics. Board Layout Consideration As with all switching regulators, careful attention must be paid to the PCB board layout and component placement. To maximize efficiency, switch rise and fall times are made as short as possible. To prevent electromagnetic interference (EMI) problems, proper layout of the high frequency switching path is essential. Place COUT next to the VOUT and GND pins. Always use a ground plane under the switching regulator to minimize interplane coupling. In addition, the ground connection for the feedback resistor R1 should be tied directly to the GND pin and not shared with any other component, ensuring a clean, noisefree connection. Recommended component placement is shown in Figure 8. Start-Up Input Current (LT3465A) As previously mentioned, the LT3465A does not have an internal soft-start circuit. Inrush current can therefore rise to approximately 400mA as shown in Figure 9 when driving 4 LEDs. The LT3465 has an internal soft-start circuit and is recommended if inrush current must be minimized. IIN 200mV/DIV FB 200mV/DIV CTRL 2V/DIV 50µs/DIV 3465A F09 Figure 9. GND L COUT RFB 1 6 2 5 3 4 CIN VIN CTRL 3465A F08a Figure 8. Recommended Component Placement. 3465afa 12 LT3465/LT3465A U TYPICAL APPLICATIO S Li-Ion to Two White LEDs 85 L1 22µH VIN = 3.6V 2 LEDs 80 3V TO 5V VOUT VIN CIN 1µF LT3465/ LT3465A FB CTRL GND COUT 1µF EFFICIENCY (%) 75 SW 70 65 60 R1 4Ω 3465A TA01a 55 CIN: TAIYO YUDEN JMK107BJ105 COUT: AVX 0603ZD105 L1: MURATA LQH32CN220 LT3465 LT3465A 50 10 0 30 20 LED CURRENT (mA) 40 50 3465A TA01b Li-Ion to Three White LEDs 85 L1 22µH VIN = 3.6V 3 LEDs 80 3V TO 5V VOUT VIN CIN 1µF LT3465/ LT3465A FB CTRL GND COUT 0.22µF 70 65 60 R1 10Ω 3465A TA02a CIN: TAIYO YUDEN JMK107BJ105 COUT: AVX 0603YD224 L1: MURATA LQH32CN220 EFFICIENCY (%) 75 SW 55 LT3465 LT3465A 50 0 5 15 10 LED CURRENT (mA) 20 3465A TA02b 3465afa 13 LT3465/LT3465A U TYPICAL APPLICATIO Li-Ion to Five White LEDs 85 L1 22µH 3V TO 5V VIN = 3.6V 5 LEDs 80 SW VOUT VIN CIN 1µF LT3465/ LT3465A FB CTRL GND COUT 0.22µF EFFICIENCY (%) 75 70 65 60 R1 10Ω 55 LT3465 LT3465A 3465A TA03a CIN: TAIYO YUDEN JMK107BJ105 COUT: TAIYO YUDEN GMK212BJ224 L1: MURATA LQH32CN220 50 0 5 15 10 LED CURRENT (mA) 20 3465A TA03b 3465afa 14 LT3465/LT3465A U PACKAGE DESCRIPTIO S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 0.62 MAX 2.90 BSC (NOTE 4) 0.95 REF 1.22 REF 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 6 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) 1.90 BSC S6 TSOT-23 0302 NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 3465afa 15 LT3465/LT3465A U TYPICAL APPLICATIO Li-Ion to Six White LEDs 85 L1 47µH/22µH VIN = 3.6V 6 LEDs 80 3V TO 5V VOUT VIN CIN 1µF COUT 0.47µF LT3465/ LT3465A FB CTRL GND EFFICIENCY (%) 75 SW 70 65 60 R1 10Ω 3465A TA04a CIN: TAIYO YUDEN JMK107BJ105 COUT: TAIYO YUDEN GMK212BJ474 L1: MURATA LQH32CN470 (LT3465) L1: MURATA LQH32CN220 (LT3465A) 55 LT3465 LT3465A 50 0 5 15 10 LED CURRENT (mA) 20 3465A TA04b RELATED PARTS PART NUMBER DESCRIPTION LT1618 Constant Current, Constant Voltage, 1.4MHz, High Efficiency Boost Regulator LT1932 Constant Current, 1.2MHz, High Efficiency White LED Boost Regulator LT1937 Constant Current, 1.2MHz, High Efficiency White LED Boost Regulator LTC®3200-5 Low Noise, 2MHz, Regulated Charge Pump White LED Driver LTC3202 LTC3205 LTC3405 LTC3405A LTC3406 LTC3406B LTC3407 LTC3411 LTC3412 LTC3440/ LTC3441 LT3466 COMMENTS Up to 16 White LEDs, VIN: 1.6V to 18V, VOUT(MAX): 34V, IQ: 1.8mA, ISHDN: <1µA, 10-Lead MS Package Up to 8 White LEDs, VIN: 1V to 10V, VOUT(MAX): 34V, IQ: 1.2mA, ISHDN: <1µA, ThinSOT Package Up to 4 White LEDs, VIN: 2.5V to 10V, VOUT(MAX): 34V, IQ: 1.9mA, ISHDN: <1µA, ThinSOT Up to 6 White LEDs, VIN: 2.7V to 4.5V, IQ: 8mA, ISHDN: <1µA, ThinSOT Package Low Noise, 1.5MHz, Regulated Charge Pump White LED Driver Up to 8 White LEDs, VIN: 2.7V to 4.5V, IQ: 5mA, ISHDN: <1µA, 10-Lead MS Package Multi-Display LED Controller 92% Efficiency, VIN: 2.8V to 4.5V, IQ: 4.2mA, ISD: <1µA, Drives Main, Sub, RGB, QFN Package 300mA (IOUT), 1.5MHz Synchronous Step-Down 95% Efficiency, VIN: 2.7V to 6V, VOUT(MIN): 0.8V, IQ: 20µA, ISHDN: <1µA, DC/DC Converter ThinSOT Package 600mA (IOUT), 1.5MHz Synchronous Step-Down 95% Efficiency, VIN: 2.5V to 5.5V, VOUT(MIN): 0.6V, IQ: 20µA, DC/DC Converter ISHDN: <1µA, ThinSOT Package Dual 600mA (IOUT), 1.5MHz Synchronous Step-Down 95% Efficiency, VIN: 2.5V to 5.5V, VOUT(MIN): 0.6V, IQ: 40µA, DC/DC Converters ISHDN: <1µA, MS10E, DFN Package 1.25A (IOUT), 4MHz Synchronous Step-Down DC/DC Converter 95% Efficiency, VIN: 2.5V to 5.5V, VOUT(MIN): 0.8V, IQ: 60µA, ISHDN: <1µA, MS10, DFN Package 2.5A (IOUT), 4MHz Synchronous Step-Down DC/DC Converter 95% Efficiency, VIN: 2.5V to 5.5V, VOUT(MIN): 0.8V, IQ: 60µA, ISHDN: <1µA, TSSOP16E Package 600mA/1.2A (IOUT), 2MHz/1MHz Synchronous Buck-Boost 95% Efficiency, VIN: 2.5V to 5.5V, VOUT(MIN): 2.5V, IQ: 25µA, DC/DC Converter ISHDN: <1µA, 10-Lead MS Package Full Function White LED Step-Up Converter with Drives Up to 20 LEDs, Independent Step-Up Converters, Built-In Schottkys VIN: 2.7µV to 24V, DFN Package 3465afa 16 Linear Technology Corporation LT/LT 0805 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2005