LT3465AES6 LINER
Document overview
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Technical content
FEATURES
, LTC and LT are registered trademarks of Linear Technology Corporation. n Inherently Matched LED Current n Drives Up to Six LEDs from a 3.6V Supply n No External Schottky Diode Required n 1.2MHz Switching Frequency (LT3465) n 2.4MHz Switching Frequency Above AM Broadcast Band (LT3465A) n Automatic Soft-Start (LT3465) n Open LED Protection n High Efficiency: 81% (LT3465) 79% (LT3465A) Typical n Requires Only 0.22µF Output Capacitor n Low Profile (1mm) SOT-23 Packaging 1.2MHz/2.4MHz White LED Step-Up Converters with Built-In Schottky in ThinSOT n Cellular Phones n PDAs, Handheld Computers n Digital Cameras n MP3 Players n GPS Receivers 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 exter- nally on competing devices. Additional features include output voltage limiting when LEDs are disconnected, one- pin shutdown and dimming control. The LT3465 has internal soft-start. 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. The LT3465 and LT3465A are available in low profile (1mm) 6-lead SOT-23 (ThinSOT TM ) packages. ThinSOT is a trademark of Linear Technology Corporation. Figure 1. Li-Ion Powered Driver for Four White LEDs
4 LEDs
Operating Temperature Range (Note 2) .. – 40°C to 85°C ORDER PART NUMBER (Note 1) ABSOLUTE AXI U RATI GSW WW U PACKAGE/ORDER I FOR ATIOUU W Consult LTC Marketing for parts specified with wider operating temperature ranges. LT3465ES6 LT3465AES6 TJMAX = 125°C, θJA = 256°C/W IN FREE AIR θJA = 120°C ON BOARD OVER GROUND PLANE The l 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. LT3465 LT3465A PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS Minimum Operating Voltage 2.7 2.7 V Maximum Operating Voltage 16 16 V Feedback Voltage 0 °C ≤ TA ≤ 85°C 188 200 212 188 200 212 mV FB Pin Bias Current 10 35 100 10 35 100 nA Maximum Duty Cycle l 90 93 90 93 % Switch Current Limit l 225 340 225 340 mA Switch VCESAT ISW = 250mA 300 300 mV Switch Leakage Current V SW = 5V 0.01 5 0.01 5 µA VCTRL for Full LED Current 1.8 1.8 V VCTRL to Shut Down Chip 50 50 mV CTRL Pin Bias Current 48 60 72 48 60 72 µA TA = 85°C 4 05 06 04 05 06 0 µA TA = –40°C 6 07 59 06 07 59 0 µA Soft-Start Time 600 µs Schottky Forward Drop I D = 150mA 0.7 0.7 V Schottky Leakage Current V R = 30V 4 4 µA
ELECTRICAL CHARACTERISTICS
5 VIN
4 CTRL
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 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.
TYPICAL PERFOR A CE CHARACTERISTICS UW Switch Saturation Voltage (VCESAT) Schottky Forward Voltage Drop Shutdown Quiescent Current (CTRL = 0V) SWITCH CURRENT (mA) SWITCH SATURATION VOLTAGE (mV)50 150 200 250 200 450 3465A G01 100 10050 250 300150 350 300 350 400 TA = 25°C SCHOTTKY FORWARD DROP (mV) SCHOTTKY FORWARD CURRENT (mA) 100 150 200 300 200 400 600 800 3465A G02 1000 1200 250 TA = 25°C VIN (V) IQ (µA) 8 14 3465A G03 4 6 10 12 TA = 25°C VFB vs VCTRL Open-Circuit Output Clamp Voltage CONTROL VOLTAGE (V) FEEDBACK VOLTAGE (mV) 100 150 3465A G04 0.5 1 1.5 250 200 TA = 25°C INPUT VOLTAGE (V) 81 2 3465A G05 46 10 14 16 OUTPUT CLAMP VOLTAGE (V) TA = 25°C Input Current in Output Open Circuit Switching Waveforms (LT3465) INPUT VOLTAGE (V) 2 2.5 INPUT CURRENT (mA) 3 4 4.5 3465A G06 3.5 5 TA = 25°C VSW 10V/DIV IL 100mA/DIV VOUT 100mV/DIV VIN = 3.6V 200ns/DIV 3465A G07a 20mA, 22µH TEMPERATURE (°C) –50 4365A G08 0 50 100 SWITCHING FREQUENCY (MHz) 3.0 2.5 2.0 1.5 1.0 0.5 LT3465 LT3465A Switching FrequencySwitching Waveforms (LT3465A) VSW 10V/DIV IL 50mA/DIV VOUT 50mV/DIV VIN = 3.6V 100ns/DIV 3465A G07b 20mA, 22µH
TYPICAL PERFOR A CE CHARACTERISTICS UW Quiescent Current (CTRL = 3V) VIN (V) IQ (mA) 0.5 1.0 1.5 2.0 2.5 3.0 51 01 5 2 0 3465A G10 –50°C 25°C 100°C DUTY CYCLE (%) CURRENT LIMIT (mA) 150 200 250 60 100 3465A G11 100 20 40 80 300 350 400 –50°C 25°C 100°C TEMPERATURE (°C) –50 EFFICIENCY (%) 3465A G12 0 50 100 20mA 10mA 15mA LT3465 LT3465A Switching Current Limit VIN = 3.6V, 4 LEDs UUUPI FU CTIO S VOUT (Pin 1): Output Pin. Connect to output capacitor and LEDs. Minimize trace between this pin and output capaci- tor 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: I mV R When V V I V R When V V LED FB CTRL LED CTRL FB CTRL 200 18 5 1 CTRL (Pin 4): Dimming Control and Shutdown Pin. Ground this pin to shut down the device. When V CTRL is greater than about 1.8V, full-scale LED current is generated. When VCTRL is less than 1V, LED current is reduced. 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. TEMPERATURE (°C) –50 SCHOTTKY LEAKAGE CURRENT (µA) VR = 25 VR = 16 VR = 10 3465A G13 05 0 100 Schottky Leakage Current TEMPERATURE (°C) –50
190 FEEDBACK VOLTAGE (mV)
–10 30 50 3465A G09 194 206 208 202 –30 10 70 90 Feedback Voltage
6 VOUT
Figure 2. LT3465 Block Diagram correct peak current level to keep the output in regulation.
3 LEDs
tor should have low core losses at 2.4MHz and low DCR. Table 1. Recommended Inductors Table 2. Recommended Ceramic Capacitor Manufacturers
waveforms are shown in Figure 5. Table 3. Inrush Peak Current in Figure 1) and the feedback reference voltage. FB selection are shown below. Table 4. RFB Resistor Value Selection Figure 6. Dimming Control Using a Filtered PWM Signal
4 LEDs, 20mA
Figure 5. Start-Up Waveforms The LT3465 and LT3465A have a built-in Schottky diode.
- · exp ± · arctan · sin arctan
- ± . 1 15 ω α ω ω α ω α α ω where L is the inductance, r is the resistance of the inductor and C is the output capacitance. For low DCR inductors, which is usually the case for this application, the peak inrush current can be simplified as follows: I V LP IN= ±.
- · exp ± ·06 α ω π
10Ω CIN 1µF COUT 0.22µF 22µH 3V TO 5V FB GND CIN: TAIYO YUDEN JMK107BJ105 COUT: AVX 0603YD224 L1: MURATA LQH32CN220 Li-Ion to Two White LEDs SW V OUT VIN LT3465/ LT3465A CTRL 3465A TA01a CIN 1µF COUT 1µF CIN: TAIYO YUDEN JMK107BJ105 COUT: AVX 0603ZD105 L1: MURATA LQH32CN220 22µH 3V TO 5V FB GND Li-Ion to Three White LEDs LED CURRENT (mA) EFFICIENCY (%) 3465A TA01b 10 20 30 50 VIN = 3.6V
2 LEDs
LED CURRENT (mA) EFFICIENCY (%) 3465A TA02b 5 10 15 20 VIN = 3.6V
10Ω CIN 1µF COUT 0.22µF 22µH 3V TO 5V FB GND CIN: TAIYO YUDEN JMK107BJ105 COUT: TAIYO YUDEN GMK212BJ224 L1: MURATA LQH32CN220 LED CURRENT (mA) EFFICIENCY (%) 3465A TA03b 5 10 15 VIN = 3.6V
5 LEDs
(Reference LTC DWG # 05-08-1636) 1.50 – 1.75 (NOTE 4)2.80 BSC 0.30 – 0.45
6 PLCS (NOTE 3)
DATUM ‘A’ 0.09 – 0.20 (NOTE 3) S6 TSOT-23 0302
2.90 BSC
(NOTE 4)
0.95 BSC
1.90 BSC
0.80 – 0.90
1.00 MAX
0.01 – 0.100.20 BSC 0.30 – 0.50 REF PIN ONE ID 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
3.85 MAX
0.62 MAX 0.95 REF RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 1.4 MIN2.62 REF
1.22 REF
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.
Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 l FAX: (408) 434-0507 l www.linear.com LINEAR TECHNOLOGY CORPORATION 2003 Li-Ion to Six White LEDs SW V OUT VIN LT3465/ LT3465A CTRL 3465A TA04a 10Ω CIN 1µF COUT 0.47µF 47µH/22µH 3V TO 5V FB GND CIN: TAIYO YUDEN JMK107BJ105 COUT: TAIYO YUDEN GMK212BJ474 L1: MURATA LQH32CN470 (LT3465) L1: MURATA LQH32CN220 (LT3465A) LT/TP 0504 1K • PRINTED IN USA RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1618 Constant Current, Constant Voltage, 1.4MHz, High Efficiency Up to 16 White LEDs, V IN: 1.6V to 18V, VOUT(MAX): 34V, IQ: 1.8mA, Boost Regulator I SHDN: <1µA, 10-Lead MS LT1932 Constant Current, 1.2MHz, High Efficiency White LED Up to 8 White LEDs, V IN: 1V to 10V, VOUT(MAX): 34V, IQ: 1.2mA, Boost Regulator I SHDN: <1µA, ThinSOT LT1937 Constant Current, 1.2MHz, High Efficiency White LED Up to 4 White LEDs, V IN: 2.5V to 10V, VOUT(MAX): 34V, IQ: 1.9mA, Boost Regulator I SHDN: <1µA, ThinSOT, SC70 LTC 3200-5 Low Noise, 2MHz, Regulated Charge Pump White LED Driver Up to 6 White LEDs, V IN: 2.7V to 4.5V, IQ: 8mA, ISHDN: <1µA, ThinSOT LTC3202 Low Noise, 1.5MHz, Regulated Charge Pump White LED Driver Up to 8 White LEDs, V IN: 2.7V to 4.5V, IQ: 5mA, ISHDN: <1µA, 10-Lead MS LTC3205 Multi-Display LED Controller 92% Efficiency, V IN: 2.8V to 4.5V, IQ: 4.2mA, ISD: <1µA, QFN, Drives Main, Sub, RGB LTC3405 300mA (I OUT), 1.5MHz Synchronous Step-Down 95% Efficiency, V IN: 2.7V to 6V, VOUT(MIN): 0.8V, IQ: 20µA, ISHDN: <1µA, LTC3405A DC/DC Converter ThinSOT LTC3406 600mA (I OUT), 1.5MHz Synchronous Step-Down 95% Efficiency, V IN: 2.5V to 5.5V, VOUT(MIN): 0.6V, IQ: 20µA, LTC3406B DC/DC Converter I SHDN: <1µA, ThinSOT LTC3407 Dual 600mA (I OUT), 1.5MHz Synchronous Step-Down 95% Efficiency, V IN: 2.5V to 5.5V, VOUT(MIN): 0.6V, IQ: 40µA, DC/DC Converters I SHDN: <1µA, MS10E, DFN LTC3411 1.25A (I OUT), 4MHz Synchronous Step-Down DC/DC Converter 95% Efficiency, V IN: 2.5V to 5.5V, VOUT(MIN): 0.8V, IQ: 60µA, ISHDN: <1µA, MS10, DFN LTC3412 2.5A (I OUT), 4MHz Synchronous Step-Down DC/DC Converter 95% Efficiency, V IN: 2.5V to 5.5V, VOUT(MIN): 0.8V, IQ: 60µA, ISHDN: <1µA, TSSOP16E LTC3440/ 600mA/1.2A (I OUT), 2MHz/1MHz Synchronous Buck-Boost 95% Efficiency, V IN: 2.5V to 5.5V, VOUT(MIN): 2.5V, IQ: 25µA, LTC3441 DC/DC Converter I SHDN: <1µA, 10-Lead MS LT3466 Full Function White LED Step-Up Converter with Drives Up to 20 LEDs, Independent Step-Up Converters, Built-In Schottkys V IN: 2.7µV to 24V, DFN Package LED CURRENT (mA) EFFICIENCY (%) 3465A TA04b 5 10 15 VIN = 3.6V