LT3003 3-Channel LED Ballaster with PWM DESCRIPTION FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ 3% LED Current Matching Up to 350mA Continuous Current per LED String Up to 3000:1 True Color PWMTM Dimming Range PWM Input Disconnects LED Strings Can Operate in Buck, Boost and Buck-Boost Modes Wide Input Range: 3V to 40V Overtemperature Outputs Works with LT1618, LT3477, LT3474, LT3475, LT3476, LTC®3783 Thermally Enhanced 10-Pin MSOP Package APPLICATIONS ■ ■ ■ ■ High Power LED Ballaster Automotive Lighting Video Cameras TFT LCD Backlighting The LT®3003 drives three separate strings of LEDs up to 350mA/channel with 3% accurate current matching, resulting in uniform LED brightness and intensity. This approach is superior to conventional methods of running three separate channels with external ballast resistors requiring expensive factory calibration. The LT3003 operates in boost, buck and buck-boost mode. A True Color PWM Dimming ratio of up to 3000:1 is achievable using a logic-level signal at the PWM pin for all modes without the need for external level-shifting circuitry. For applications with input supply above and below the output voltage of the LED strings, the LT3003 allows the LEDs to be returned to the input supply (buck-boost mode) instead of being limited to only SEPIC solutions. The LT3003 is ideal for high power LED driver applications such as TFT LCD backlighting and heads-up displays. Additional overtemperature outputs allow appropriate system management for increased reliability. The LT3003 is available in a small 10-pin MSE package. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. True Color PWM is a trademark of Linear Technolology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION Efficiency Buck Mode LT3003 with the LT3476 90 PVIN 32V 8 × 3 = 24 LEDs 350mA PER STRING 0.1Ω LED1 VMAX SHDN PWM DIMMING CAP LED VIN 10µF 1µF LT3003 PWM OT1 OT2 VEE 1nF SW 80 75 70 65 0.33µF VC SIMPLIFIED LT3476 GND LED3 VIN PWM GND VIN 3V TO 16V LED2 85 EFFICIENCY (%) 1µF 10µH 60 PVIN = 32V NUMBER OF LEDS = 8 × 3 = 24 0 1000 400 600 800 200 TOTAL LED CURRENT (mA) 1200 3003 TA01a 3003 TA01b 3003fa 1 LT3003 ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) VIN ............................................................................40V LED1, LED2, LED3 ....................................................48V VMAX, SHDN ..............................................................48V VIN – VEE ...................................................................36V VEE ............................................................................36V PWM .........................................................................15V OT1, OT2.....................................................................6V Operating Junction Temperature Range (Notes 2, 3, 4) ........................................ –40°C to 125°C Storage Temperature Range................... –65°C to 150°C Lead Temperature (Soldering, 10 sec) .................. 300°C TOP VIEW LED1 LED2 LED3 VMAX VIN 1 2 3 4 5 10 9 8 7 6 11 VEE SHDN OT2 OT1 PWM MSE PACKAGE 10-LEAD PLASTIC MSOP TJMAX = 125°C, θJA = 35°C/W EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB ORDER PART NUMBER MSE PART MARKING LT3003EMSE LTCFF 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. PWM = 1V, VMAX = 4V, VIN = 3V, VEE = 0V, ILED2 = 100mA, OT1 = OT2 = Open, SHDN = VIN. PARAMETER CONDITIONS VIN Operational Input Voltage VEE = 0V, ILED1,2,3 = 100mA VEE = 4V, ILED1,2,3 = 100mA Minimum (VIN – VEE) VEE = 0V to 36V VIN Quiescent Current PWM = 1V, ILED1,2,3 = 100mA PWM = 0V, VLED1 = VLED2 = VLED3 VIN Shutdown Current SHDN = 0V, ILED1,2,3 = 0mA VMAX Quiescent Current PWM = 1V, ILED2 = 100mA PWM = 0V, VLED1 = VLED2 = VLED3 SHDN Pin Threshold ILED2 = 100mA, VLED1 = VLED2 = VLED3 LED Current Matching ILED2 = 350mA, VLED1 = VLED2 = VLED3 |LED2 – LED1|, |LED2 – LED3| LED Current Matching with LED Pin Voltage Mismatch MIN ● 3 2 ● TYP MAX UNITS 36 40 V V 2.7 3 V 10.5 470 600 4 10 µA 55 20 90 300 µA nA mA µA 0.25 0.7 1 V –3 0 +3 % ILED2 = 350mA, (|VLED2 – VLED1| + |VLED2 – VLED3|) = 700mV –3.5 0.5 +3.5 % LED Pin Voltage ILED2 = 100mA 0.7 0.8 0.9 V LED1, LED2, LED3 Maximum Current VLED1,2,3 < 1.5V 375 500 550 mA LED1, LED2, LED3 Maximum Leakage Current PWM = 0V, VLED1,2,3 = 48V 0.1 1 µA PWM Switching Threshold ILED1,2,3 = 100mA 0.5 0.7 V 1 µA ● 0.3 Turn-On Delay (PWM On to ILED On) PWM = 0V to 1V, ILED > 50mA VEE Pin Current in Buck Mode PWM = 0V, VMAX = 40V, VIN = 39V, VEE = 36V 0.1 2 Overtemperature Sense Point (OT1, OT2) (Note 4) 125 °C Overtemperature Hysteresis Point (Note 5) –6° from Overtemp Sense Point °C OT1 Pull-Down Current OT1 = 0.3V (Note 4) 100 µs µA 3003fa 2 LT3003 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. PWM = 1V, VMAX = 4V, VIN = 3V, VEE = 0V, ILED2 = 100mA, OT1 = OT2 = Open, SHDN = VIN. PARAMETER CONDITIONS MIN OT2 Pull-Down Current OT2 = 0.3V (Note 4) 300 OT1, OT2 Leakage Current OT1 = OT2 = 5V 35 1.5 1.0 0.5 0 0 50 75 100 25 –50 –25 JUNCTION TEMPERATURE (°C) 500 TJ = 27°C 25 20 15 10 5 50 100 150 250 200 ILED (mA) 4 3 2 1 0 50 25 0 75 100 –50 –25 JUNCTION TEMPERATURE (°C) 125 3003 G04 150 100 125 (VLED1,2,3 – VEE) vs ILED 1150 6 1100 (VLED1,2,3 – VEE) (mV) VIN SHUTDOWN CURRENT (µA) VMAX PIN CURRENT (nA) 5 200 3003 G03 SHDN = 0 6 250 VIN Shutdown Current vs Temperature 10µs AFTER PWM = 0 7 300 0 50 25 0 75 100 –50 –25 JUNCTION TEMPERATURE (°C) 350 300 7 8 350 3003 G02 VMAX Pin Current vs Temperature 9 400 50 3003 G01 10 10µs AFTER PWM = 0 450 30 0 125 µA VEE Pin Current (Out of the Pin) vs Temperature VEE PIN CURRENT • –1 (nA) INPUT QUIESCENT CURRENT (mA) ILED1,3 vs ILED2 (%) 2.0 µA TA = 25°C unless otherwise noted. VIN Quiescent Current vs ILED ILED1,3 – ILED2 ILED2 2.5 I LED2 = 350mA VLED1 = VLED2 = VLED3 UNITS Note 3: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125°C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability. Note 4: Correlation to static test at TA = 25°C. Note 5: Guaranteed by design. TYPICAL PERFORMANCE CHARACTERISTICS 3.0 MAX 1 Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LT3003E is guaranteed to meet performance specifications from 0°C to 85°C junction temperature. Specifications over the –40°C to 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. ILED1,3 to ILED2 Matching TYP 5 4 3 2 1 1050 1000 950 900 850 0 50 100 –50 –25 25 75 0 JUNCTION TEMPERATURE (°C) 125 3003 G05 800 50 100 150 200 250 300 350 400 ILED (mA) 3003 G06 3003fa 3 LT3003 TYPICAL PERFORMANCE CHARACTERISTICS VIN Shutdown Current vs VIN VIN Quiescent Current vs ILED 35 16 30 14 VIN SHUTDOWN CURRENT (µA) VIN QUIESCENT CURRENT (mA) TA = 25°C unless otherwise noted. 25 20 15 10 5 SHDN = 0 12 10 8 6 4 2 0 0 50 100 150 250 200 ILED (mA) 300 350 3003 G07 3 8 13 23 18 VIN (V) 28 33 38 3003 G08 PIN FUNCTIONS LED1 (Pin 1): Controlled current input for a string of LEDs with a cathode lead connected to the pin. Connect the first string of LEDs to this pin. LED2 (Pin 2): Controlled current input for a string of LEDs with a cathode lead connected to the pin. Connect the second string of LEDs to this pin. LED3 (Pin 3): Controlled current input for a string of LEDs with a cathode lead connected to the pin. Connect the third string of LEDs to this pin. VMAX (Pin 4): • Boost: Connect to VOUT • Buck Mode: Connect to Input Supply • Buck-Boost Mode: Connect to VOUT VIN (Pin 5): Input Supply, Upper Rail. This pin must be locally bypassed with a capacitor to ground. VIN powers the internal control circuitry. • Boost: Connect to Input Supply • Buck Mode: Connect to Input Supply • Buck-Boost Mode: Connect to VOUT PWM (Pin 6): Input Pin for PWM Dimming Control. A PWM signal above 0.5V (on threshold) turns the LT3003 channels on. A PWM signal below 0.5V completely disconnects each LED string. If the application does not require PWM dimming, then the PWM pin can be left either open (an internal 10µA source current pulls PWM high) or it can be connected to a supply between 0.5V to 15V. OT1 (Pin 7): Overtemperature Output. OT1 pulls 100µA from the pin when the junction temperature exceeds 125°C. The part has to cool down by 6°C for the flag to reset; ideal for providing an overtemperature flag to the system microprocessor. OT2 (Pin 8): Overtemperature Output. OT2 Pulls 300µA from the pin when the junction temperature exceeds 125°C. The part has to cool down by 6°C for the flag to reset; ideal for connecting to the switching regulator gm error amplifier output to defeat switching. SHDN (Pin 9): Micropower Shutdown Pin. Below 0.7V shuts down the IC. Typically IVIN = 4µA for SHDN = 0V. • Boost: Connect to System Shutdown Signal or VIN • Buck Mode: Connect to System Shutdown Signal or VIN • Buck-Boost Mode: If PWM dimming, connect to PWM (Pin 6); if no PWM dimming, connect to system shutdown signal or VIN 3003fa 4 LT3003 PIN FUNCTIONS Exposed Pad (Pin 11): GND. The ground for the IC should be soldered to a continuous copper ground plane under the LT3003 die. Soldering the Exposed Pad to the copper ground plane under the device will reduce thermal resistance and increase the power capability of the LT3003. VEE (Pin 10): Lower Rail. • Boost: Connect to System Ground • Buck Mode: Connect to Inductor • Buck-Boost Mode: Connect to Input Supply BLOCK DIAGRAM 1 4 LED1 2 VMAX 3 LED3 LED2 VIN B1 + + B2 – B3 – VEE 10 B1 B2 B3 VIN + PWM LOGIC – 5 3V VEE 6 PWM 0.5V + + – – BIAS BG THERMAL SHUTDOWN BG 125°C SHDN 0.7V OT1 OT2 9 7 8 150°C 11 EXPOSED PAD 3003 F01 Figure 1. Block Diagram 3003fa 5 LT3003 OPERATION The LT3003 is an easy-to-use 3-channel LED ballaster. It allows three strings of LEDs to be driven in parallel with accurate LED current matching. A PWM pin is also provided allowing LED currents to be turned on and off at very low duty cycles for very wide LED dimming ranges. For reliable system thermal management, two output flags, OT1 and OT2, are provided to indicate when the junction temperature exceeds 125°C. The Block Diagram in Figure 1 best illustrates the features of LT3003. The LT3003 internal bias circuitry is turned on when VIN > 3V and SHDN > 0.7V. For LED current to be active in each channel, the PWM pin must exceed 0.5V. VMAX should be connected to the highest supply in the application (see various application modes of boost, buck, buck-boost in the Typical Applications section). The LT3003 ballasting feature is achieved by using the current monitored in the LED2 channel to control the current in channels LED1 and LED3. A servo loop exists for each channel LED1 and LED3 that compares the current in each channel to the LED2 reference channel. The current in LED2 channel is determined by the LED current programmed by the partner LED driver. Details of how LED current can be programmed by the partner IC are covered in the Typical Applications section using various ICs as LED drivers. Maximum fault current in each of the LT3003 LED pins is internally limited to 550mA. If any LED string experiences an open-circuit fault, all LED string currents are turned off. The LT3003 PWM pin has unique level-shifting circuitry to allow a simple logic-level PWM signal to turn each LED pin current on and off regardless of the VEE pin voltage. This allows very simple PWM dimming control of LED current without any need for external level-shifting components in buck mode and buck-boost mode applications. Care is taken to ensure low current (nano amps) in the VEE and VMAX pins 10µs after PWM low edge. This feature minimizes leakage currents in each application to maximize PWM dimming ratio. Details of PWM dimming and critical parameters are given in the Applications Information section PWM Dimming. The LT3003 incorporates internal junction temperature sensing and provides two open-collector outputs, OT1 and OT2, which become active low when junction temperature exceeds 125°C. OT1 is sized to pull 100µA and can be used as an input to the microprocessor for system thermal management. OT2 is sized to pull 300µA to defeat switching for most of LTC’s LED drivers by pulling down the gm error amplifier output. LT3003 is forced to a “zero LED current state” by a special internal protection circuit when junction temperature reaches 150°C. To calculate the LT3003 junction temperature, see Thermal Calculations in the Applications Information section. 3003fa 6 LT3003 APPLICATIONS INFORMATION Input Capacitor Selection PWM Dimming The LT3003 is typically driven from the same input voltage used for the partner LED driver IC. The LED driver and inductor govern the requirements for the input capacitor of the application. A ceramic input capacitor in the range of 1µF to 10µF works for most applications. In cases where the LT3003 input voltage is derived separately from the LED driver, a 1µF input capacitor works well. The LT3003 has a wide PWM dimming range for constant color LED dimming. PWM dimming is superior to analog dimming as it preserves true color quality. PWM dimming control with the LT3003 is achieved using a simple ground referenced PWM signal with a 0.5V on/off threshold. The LEDs operate at either programmed or zero current but their brightness changes with the PWM signal duty cycle. When PWM is low, LED strings are completely disconnected. In addition, the LT3003 switches to low power standby mode ~10µs after PWM low edge, resulting in higher system power efficiency. LED Current Matching An LED driver programs the LED current and LT3003 actively ballasts three separate strings of LEDs. The currents in all three channels will be matched to better than ±3%. To achieve best current matching, (VIN – VEE) should be between 3V and 10V. A low (VIN – VEE) also minimizes LT3003 internal power dissipation (see Thermal Calculation section for more information). 10 ILED2 = 350mA ∆VLED = 1.4V ILED1,3 vs ILED2 (%) 8 6 For the widest dimming range, the PWM signal should be 100Hz. The human eye is typically sensitive to flickering below ~80Hz. Operating the PWM higher than 100Hz results in a reduced PWM dimming ratio. Achieving high PWM dimming ratios require attention to circuit leakages, such as reverse bias leakage currents through the external Schottky. Hence, for high PWM dimming ratios, components should be chosen to minimize leakage currents. If an application does not require PWM dimming, the PWM pin can be left open (unconnected) and an internal 10µA source current pulls PWM high. 4 2 Boost PWM Dimming 0 3 6 9 12 15 18 21 24 27 30 33 36 VIN – VEE (V) 3003 F02 Figure 2. ILED Matching vs (VIN – VEE) The LT3003 supports up to a 3000:1 PWM dimming ratio with a 100Hz PWM dimming frequency. To achieve such high PWM ratios, leakages of the LED driver and other external components should be minimal. LED Pin Current Range Buck Mode: PWM Dimming The steady-state operational current range for each LED pin is between 100mA and 350mA. Internal protection circuitry limits absolute maximum pin current to 550mA. The LT3003 supports up to a 3000:1 PWM dimming ratio in buck mode. The PWM dimming in buck mode is achieved by an architecture that allows the LT3003 power ground (VEE) to move with output capacitor voltage. PWM dimming control is achieved by a simple ground referenced PWM signal, eliminating the need for any external levelshift component. LED Open-Circuit Protection If any LED string is open, then currents in all three channels reduce to zero. The driver chip, which supplies LED current, should have an overvoltage clamp to protect the LT3003 from high LED pin voltages. High PWM dimming ratios require very low VEE and VMAX pin currents during the PWM off state. The LT3003 3003fa 7 LT3003 APPLICATIONS INFORMATION D1 L1 VIN C1 C2 RSENSE + SW EA DRV D1A D2A D3A D1B D2B D3B D1C D2C D3C Buck-Boost Mode: PWM Dimming LED DRIVER LED2 LED1 PWM PWM SHDN VIN LED3 LT3003 VEE uses novel circuit techniques to reduce VEE and VMAX pin currents to nano amp range ~10µs after PWM low edge. This preserves the output capacitor voltage and results in higher PWM dimming ratios. VMAX The LT3003 can also perform PWM dimming in buck-boost mode. The buck-boost configuration requires the PWM and SHDN pins to be tied together. This configuration can support up to a 2000:1 PWM dimming ratio. OT1 OT2 OT1 OT2 VIN VMAX GND GND 3003 F03 LT3003 VEE Figure 3. Boost Mode D3C D3B D3A D2C D2B D2A D1C D1B D1A LED3 LED2 RSENSE LED1 VIN SHDN PWM C1 + C1 D1A D2A D3A D1B D2B D3B D1C D2C D3C LED1 LED2 PWM LED3 C2 SW EA PWM DRV VIN LT3003 VEE D1 L1 VIN RSENSE GND LED DRIVER VMAX OT1 OT2 SHDN 3003 F05 Figure 5. Buck-Boost Mode Overtemperature Protection PWM L1 C2 D1 3003 F04 + SW EA DRV LED DRIVER Figure 4. Buck Mode The LT3003 incorporates internal junction temperature sensing and provides two open-collector outputs, OT1 and OT2, which become active low when junction temperature exceeds 125°C. The active OT1 output can sink 100µA of current and can be connected to system microprocessor. The active low OT2 output can sink 300µA of current and can be connected to the switching regulator’s gm error amplifier output to defeat switching. The LT3003 has to cool down by 6°C (119°C) for OT1 and OT2 outputs to reset (collector outputs high). 3003fa 8 LT3003 APPLICATIONS INFORMATION In addition, LT3003 has an internal 150°C overtemperature protection circuitry that resets the chip to zero LED current mode. This prevents the chip from continuous operation at high temperature. Thermal Calculations To maximize output power capability in an application without exceeding the LT3003 125°C maximum operational junction temperature, it is useful to be able to calculate power dissipation within the IC. The power dissipation within the LT3003 comes from four main sources: switch DC loss, switch loss due to LED VLED mismatch and input quiescent current. 1. Switch DC Loss: PSW(DC) = ILED • VLED • 3 (See (VLED1,2,3 – VEE) vs ILED Typical Performance Characteristics graph.) 2. Switch Loss due to VLED Mismatch: PSW(ΔVLED) = Total VLED mismatch • ILED 3. Input Quiescent Loss: PQ = (VIN – VEE) • (IQ – 1mA) + 1mA • VIN IQ = 3 • ILED + 3mA 40 4. Total Power Dissipation: PTOT = PSW(DC) + PSW(ΔVLED) + PQ 5. LT3003 Junction Temperature: TJ (LT3003) = TA + θJA(PTOT); θJA(PTOT) = PTOT • 35°C/W Example VIN = 3V; VEE = 0V; ILED = 350mA/string; • IQ = 3 • 350mA + 3mA = 29.25mA 40 Total VLED mismatch = 1V: • e.g., LED string 1 voltage drop = 6V; LED string 2 voltage drop = 5.7V; LED string 3 voltage drop = 5.3V • Total VLED mismatch = (6V – 5.7V) + (6V – 5.3V) = 1V VLED = 1.1V at ILED = 350mA (see (VLED – VEE) vs ILED Typical Performance Characteristics graph). 1. PSW(DC) = 3 • 350mA • (1.1V) = 1.16W 2. PSW(LED) = 1000mV • 350mA = 350mW 3. PQ = (3 – 0) • (29.25 – 1)mA + 3 • 1mA = 88mW 4. PTOT = 1.1W + 350mW + 88mW ≈1.6W The LT3003 uses a thermally enhanced 10-lead MSE package. With proper soldering of the Exposed Pad to the underside of the package, combined with a full copper plane underneath the device, the thermal resistance (θJA) is about 35°C/W. For an ambient temperature of TA = 25°C, the junction temperature of the LT3003, for the example application described above, can be calculated as: 5. TJ = TA + θJA • PTOT = 25°C + 35°C/W • 1.6W = 81°C Minimizing LT3003 Internal Power Dissipation The LT3003 requires at least 3V headroom between VIN and VEE. Hence, for systems with high system input voltage and low VEE (such as running multiple series LEDs in a Buck Mode), it is beneficial to lower the level of VIN pin voltage (LT3003 upper rail) with an external zener to reduce power dissipation in the chip. Therefore, it is recommended to limit (VIN – VEE) to less than 10V. To achieve best performance, (VIN – VEE) should equal 3V. 3003fa 9 LT3003 TYPICAL APPLICATIONS 1.05A Buck Mode LT3003 with the LT3476 PVIN 32V D1 D2 20V 4.7µF 35V VIN 3V TO 16V 1µF 5 C1 1µF 18 7 37 1 33 SHDN VIN REF CAP1 VADJ1 LED1 R1 0.1Ω 3 LED 2 6 PWM1 LED LED 8 LEDs PER STRING; 350mA PER STRING RT SW1 R3 21k SW1 VC1 GND 39 35 LED1 SHDN 9 LED2 VEE LT3003 10 C2 0.33µF L1 10µH LED 3 LT3476 VMAX LED 2 LED 4 VIN LED3 PWM OT1 OT2 6 7 8 GND 11 29 3003 TA02a 28 1 1nF C1: TDK C1608X7R1C105K C2: TAIYO YUDEN GMK212BJ334MG-T D1: DIODES INC. DFLS140 L1: TOKO A916CY-100M-P3 LED: LUMILEDS LUXEON NC 19-21, 30-32 Efficiency 90 EFFICIENCY (%) 85 80 75 70 65 60 PVIN = 33V NUMBER OF LEDS = 8 × 3 = 24 0 1000 400 600 800 200 TOTAL LED CURRENT (mA) 1200 3003 TA02b 3003fa 10 LT3003 TYPICAL APPLICATIONS 330mA Boost LT3003 with the LT3477 VIN 8V TO 16V L1 4.7µH C1 1µF 25V 13 1 9 3 7 8 5 16 IADJ1 IADJ2 SHDN LT3477 ISP2 FBP ISN2 VREF VC RT GND Q1 2N7002 GND 15 21 C4 4.7µF 50V R5 1.15M 1% 17 SW SW 6 FBN 18 NC 19 NC 20 NC VIN D2 1N4148W PWM 14 ISP1 ISN1 10 D1 VOUT R6 45.3k 1% 11 R4 0.3Ω 1% 12 2 R3 6.81k ILED 110mA PER STRING 6 to 8 LEDs PER STRING SS 4 C3 0.033µF C2 22nF 6 C1, C3: TAIYO YUDEN TMK212BJ105MG-BR C4: MURATA GRM32ER71H475KA88L D1: DIODES INC. DFLS140 L1: SUMIDA CDRH5D16-4R7 7 8 3 2 1 LED1 LED2 LED3 VMAX PWM 4 VOUT VIN 4V LT3003 OT1 VIN SHDN OT2 5 C3 1µF 25V 9 VEE GND 11 10 3003 TA03a PWM Dimming Efficiency 100 1000 ILED = 110mA PER STRING 95 NUMBER OF LEDS = 8 × 3 = 24 ILED = 110mA PER STRING NUMBER OF LEDS = 8 × 3 = 24 90 EFFICIENCY (%) TOTAL ILED (mA) 100 10 85 80 75 70 65 1 60 55 0.1 50 1 100 1000 10 PWM DIMMING RATIO 10000 3003 TA03b 8 9 10 11 12 13 VIN (V) 14 15 16 3003 TA03b 3003fa 11 LT3003 TYPICAL APPLICATIONS 300mA Buck-Boost Mode LT3003 with the LT3477 D3 1µF 6 4 5 VMAX VIN LED1 VEE 1 LED9 LED10 LED11 LED12 7 LT3003 GND LED2 2 LED5 LED6 LED7 LED8 LED3 SHDN PWM OT2 9 VIN 8V TO 16V 6 3 OT1 8 LED1 LED2 LED3 LED4 7 ILED = 100mA 33µF CER ISP1 ISN1 VIN IADJ2 33nF CER SHDN ISP2 SS ISN2 VC 10k RT GND 6.81k NMOS 5V 0V FBP VREF LT3477 D2 PWM 3.3µF 50V CER 280k SW FBN IADJ1 RSENSE 0.33Ω D1 10µH 3003 TA04a D1: ZETEX ZLLS1000 D2: DIODES INC 1N4148 D3: PHILIPS PDZ9.1B NMOS: ZETEX 2N7002 10nF 100Hz Efficiency 80 NUMBER OF LEDS = 4 × 3 = 12 EFFICIENCY (%) 78 76 ILED = 200mA 74 72 ILED = 100mA 70 68 6 8 10 12 VIN (V) 14 16 18 3003 TA04b 3003fa 12 LT3003 TYPICAL APPLICATIONS 1A Buck Mode LT3003 with the LT1618 VIN 32V RSENSE 0.05Ω 1%, 1A C1 4.7µF 50V CER ILED = 333mA PER STRING LED1 LED2 LED3 OT1 VMAX D1 14V LT3003 VIN OT2 R1 1M PWM SHDN GND C3 1µF 50V ZLLS1000 SW ISP VIN 5V L1 10µH 1.5A NC ISN VEE COUT 1µF 50V CER VIN LT1618 1N4148W 1µF 10V CER SHDN IADJ VC GND FB Q4 2N7002 PWM 100Hz, 5V 500:1 MAX PWM DIMMING RATIO 1k 10nF 220pF 3003 TA05a Efficiency 83 NUMBER OF LEDS = 6 × 3 = 18 EFFICIENCY (%) 82 81 80 79 78 77 0 0.2 0.4 0.6 0.8 TOTAL LED CURRENT (A) 1.0 3003 TA05b 3003fa 13 LT3003 TYPICAL APPLICATIONS 1A Buck LT3003 with the LT3475 R1 20k VIN 24V CIN1 4.7µF 50V 5 20 3 D1 1N4448W COUT1 2.2µF 16V LED7 LED4 LED8 LED5 L1 10µH SUMIDA D2 B240A LED9 1 C1 0.22µF X5R 4 2 LED6 17 LED1 LED2 R8 2.0k LED3 R4 1.0k 19 18 330mA PER STRING 3S 3P LUXEON I WHITE LED1 VEE LED2 SHDN LED3 LT3003 VMAX R10 10k C3 3300pF C5 0.1µF 6 16 VIN VIN SHDN PWM1 PWM2 BOOST1 BOOST2 OUT1 SW1 OUT2 SW2 LT3475 LED1 LED2 11 8 10 7 9 SECOND CHANNEL REF VADJ2 VADJ1 VC2 VC1 GND 15 12 13 GND RT 14 21 R13 1.0M OT2 OT1 C7 220pF PWM VIN ONE OF TWO CHANNELS SHOWN GND C3 1µF 50V fSW = 1MHz 3003 TA06a PWM1 100Hz 2000:1 MAX PWM DIMMING RATIO 20V R12 11.8k 1% Q3 2N7002 Efficiency 100 95 EFFICIENCY (%) 90 85 80 75 70 65 65 55 50 0 0.2 0.6 0.8 1.0 0.4 TOTAL LED CURRENT (A) 1.2 3003 TA06b 3003fa 14 LT3003 PACKAGE DESCRIPTION MSE Package 10-Lead Plastic MSOP (Reference LTC DWG # 05-08-1664) BOTTOM VIEW OF EXPOSED PAD OPTION 2.794 ± 0.102 (.110 ± .004) 5.23 (.206) MIN 0.889 ± 0.127 (.035 ± .005) 1 2.06 ± 0.102 (.081 ± .004) 1.83 ± 0.102 (.072 ± .004) 2.083 ± 0.102 3.20 – 3.45 (.082 ± .004) (.126 – .136) 10 0.50 0.305 ± 0.038 (.0197) (.0120 ± .0015) BSC TYP RECOMMENDED SOLDER PAD LAYOUT 3.00 ± 0.102 (.118 ± .004) (NOTE 3) 10 9 8 7 6 3.00 ± 0.102 (.118 ± .004) (NOTE 4) 4.90 ± 0.152 (.193 ± .006) 0.254 (.010) DETAIL “A” 0° – 6° TYP 1 2 3 4 5 GAUGE PLANE 0.53 ± 0.152 (.021 ± .006) DETAIL “A” 0.18 (.007) 0.497 ± 0.076 (.0196 ± .003) REF SEATING PLANE 0.86 (.034) REF 1.10 (.043) MAX 0.17 – 0.27 (.007 – .011) TYP 0.50 (.0197) BSC 0.127 ± 0.076 (.005 ± .003) MSOP (MSE) 0603 NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 3003fa 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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 15 LT3003 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1618 Constant-Current/Constant-Voltage DC/DC Converter Drives 20 White LEDs from Li-Ion, 10-Lead MS Package LT1932 Constant Current,1.2MHz, High Efficiency White LED Boost Regulator VIN: 1V to 10V, VOUT(MAX) = 34V, IQ = 1.2mA, ISD < 1µA, ThinSOTTM Package LT1942 Quad DC/DC Converter for Triple Output TFT Supply Plus Boost LED Driver, with a 2-Channel Ballaster TFT Supply: Three Switching Regulators (Two Boost, One Inverting) LED Supply: Up to Two Strings of 10 LEDs. VIN: 2.6V to 16V, VOUT(MAX) = 45V, IQ = 7mA, ISD < 1µA, Low Profile QFN package. LT3475 36V, 2MHz, Dual 1.5A Step-Down LED Driver VIN: 4V to 36V, 200kHz to 2MHz, TSSOP20E Package, 3000:1 Dimming LT3477 3A, 3.5mHz, Constant-Current DC/DC Converter with Dual Rail Sense. Can Drive LEDs in Boost, Buck and Buck-Boost Configurations VIN: 2.5V to 25V, VOUT(MAX) = 42V, ISD < 1µA, QFN/TSSOP Packages LT3478 4.5A Constant Current BOOST LED Driver with PWM VIN: 2.7V to 36V, VOUT(MAX) = 40V, ILED(MAX) = 1.05A, ISD < 5µA, FE16 Package LT3479 3A, 3.5MHz, 42V Full Featured Boost/Inverter Converter with Soft-Start VIN: 2.5V to 24V, VOUT(MAX) = 40V, IQ = 5mA, ISD < 1µA, DFN/TSSOP Packages LT3474 36V, 2MHz, Step-Down 1A LED Driver VIN: 4V to 36V, 200kHz to 2MHz, TSSOP16E Package, 400:1 Dimming LTC3205 Multi-Display LED Controller, Step-Up/Step-Down Fractional Charge Pump, Independent Current and Dimming Control VIN: 2.8V to 4.5V, 800MHz, QFN Package LTC3783 PWM LED Power and Boost, Flyback and SEPIC Controller VIN: 3.6V to 36V, 300kHz, DFN, TSSOP16E Package, 3000:1 Dimming ThinSOT is a trademark of Linear Technology Corporation. 3003fa 16 Linear Technology Corporation LT 0107 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 2006