3599

LT3599 LINER

Document overview

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Technical content

FEATURES

APPLICATIONS

DESCRIPTION

4-Channel 120mA LED Driver with ±1.5% Current Matching The L T®3599 is a fi xed frequency 2A step-up DC/DC converter designed to drive four strings of 120mA LEDs up to a 44V output voltage. The switching frequency is programmable from 200kHz to 2.1MHz through an external resistor . LED dimming can be achieved with analog dimming on the CTRL pin, and with pulse width modulation dimming on the PWM pin. The L T3599 accurately regulates LED current even when the input voltage is higher than the LED output voltage. Additional features include programmable LED current derating, switching frequency synchronization to an ex- ternal clock, LED string disable control, OPENLED alert pin, SHORTLED alert pins and programmable maximum output voltage when all LED strings are disconnected. The L T3599 is available in the thermally enhanced 32-pin (5mm × 5mm) QFN and 28-pin TSSOP packages. 90% Effi cient 12W LED Driver n T rue Color PWMTM Dimming Ratio Up to 3000:1 n Drives Four Strings of LEDs at Up to 120mA n ±1.5% Accurate LED Current Matching n Wide Input Voltage Range: 3.1V to 30V n Output Voltage Up to 44V n Regulates LED Current Even When V IN > VOUT n Disconnects LEDs in Shutdown n Programmable Maximum V OUT (Regulated) n Open/Short LED Protection and Fault Flags n Programmable LED Current Derating n Adjustable Frequency: 200kHz to 2.1MHz n Synchronizable to an External Clock n Analog Dimming Up to 20:1 n Programmable Input UVLO with Hysteresis n Thermally Enhanced 32-Pin (5mm × 5mm) QFN and 28-Pin TSSOP Packages n Automotive Navigation TFT LCD Displays n Desktop and Notebook TFT LCD Displays LED Current Matching L T, L TC and L TM are registered trademarks of Linear Technology Corporation. T rue Color PWM is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 7199560. 3.3μF 47nF 10μH 4.7μF 100pF 10nF

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VO_SW FBOPENLED SHORTLED PWM SHDN/UVLO RT SYNC PWM 80mA PER STRING CTRL VREF TSET LED1 LED2 LED3 LED4 VOUTSWVIN VCSS GNDISET 220pF 31.6k PVIN 8V TO 24V VIN VIN 16.5k 53.6k 100k DISABLE4 100k 31.6k 33.2k 52.3k 80.6k 200k 1μF VIN 3.1V TO 5.5V TEMPERATURE (°C) –50 –1.5 MATCHING (%) –1.0 0.5 1.0 1.5 0 50 75 –0.5 –25 25 100 125

3599 TA01b

V PWM, SYNC, CTRL, FB Voltage, T (Note 1) ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE L T3599EFE#PBF L T3599EFE#TRPBF L T3599FE 28-Lead (4mm × 4mm) Plastic FE –40°C to 125°C L T3599IFE#PBF L T3599IFE#TRPBF L T3599FE 28-Lead (4mm × 4mm) Plastic FE –40°C to 125°C L T3599EUH#PBF L T3599EUH#TRPBF 3599 32-Lead (5mm × 5mm) Plastic QFN –40°C to 125°C L T3599IUH#PBF L T3599IUH#TRPBF 3599 32-Lead (5mm × 5mm) Plastic QFN –40°C to 125°C Consult L TC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container . Consult L TC Marketing for information on non-standard lead based fi nish parts. For more information on lead free part marking, go to: http://www.linear .com/leadfree/ For more information on tape and reel specifi cations, go to: http://www.linear .com/tapeandreel/ Operating Junction Temperature Range ...–40°C to 125°C TOP VIEW FE PACKAGE 28-LEAD PLASTIC TSSOP SW V OUT VO_SW LED1 LED2 LED3 LED4 DISABLE4 SHORTLED NC OPENLED NC I SET CTRL VIN SHDN/UVLO NC GND V REF SS R T PWM NC SYNC NC T SET FB V C TJMAX = 125°C, θJA = 28°C/W EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB 31 30 29 28 27 26 25 9 10 11 12 TOP VIEW UH PACKAGE 32-LEAD (5mm s 5mm) PLASTIC QFN 13 14 15 16 1VOUT VO_SW LED1 LED2 LED3 LED4 DISABLE4 SHORTLED NC NC GND V REF SS R T PWM SYNC NC NC NC SW VIN SHDN/UVLO NC NC NC NC OPENLED I SET CTRL VC FB TSET TJMAX = 125°C, θJA = 34°C/W EXPOSED PAD (PIN 33) IS GND, MUST BE SOLDERED TO PCB

ELECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 5V , VSHDN = 5V , unless otherwise noted. (Note 2) PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Operating Voltage l 2.7 3.1 V Maximum Operating Voltage l 30 V Reference Voltage VREF I(VREF ) = 0μA l 1.21 1.20 1.227 1.24 1.25 V V Reference Voltage Line Regulation I(V REF ) = 0μA, 3.1V < VIN < 30V , VC = 0.7V 0.01 0.03 %/V Maximum VREF Pin Current (Note 3) 100 μA VREF Load Regulation 0 < I(V REF) ≤ 100μA (Max) 1 mV Feedback Voltage l 1.196 1.223 1.250 V FB Pin Bias Current (Note 3) 100 250 nA FB Error Amp T ransconductance ΔI = 5μA 200 μmhos FB Error Amp Voltage Gain 210 V/V Current Loop Amp T ransconductance 50 μmhos Current Loop Amp Voltage Gain 50 V/V V C Source Current (Out of Pin) LED1-4 = 0.4V , FB = 1V , V C = 1.5V 8 μA VC Sink Current (OVP Mode) LED1-4 = 0.4V , FB = 1.5V , V C = 1.5V 15 μA Quiescent Current V SHDN = 5V , PWM = 0V , Not Switching, VC = 0.7V 3 4.8 mA Quiescent Current in Shutdown V SHDN = 0V 0 1 μA LED Current R ISET = 13.3k 96 99 102 mA LED String Current Matching 100mA LED Current l ±0.25 ±1.5 % LED Open Detection Threshold (VLED–GND) FB > 1.25V 0.3 0.4 V LED Short Detection Threshold (VOUT –VLED) 0.8 1.5 2.2 V LED Regulation Voltage 0.77 V LED1-4 Leakage Current V LED1-4 = 45V 0.1 1 μA CTRL Pin Bias Current V CTRL = 0.8V (Note 3) 100 200 nA Switching Frequency R T = 324k RT = 53.6k RT = 20k 176 0.9 1.82 198 2.06 220 1.1 2.3 kHz MHz MHz T SET Voltage 575 mV Maximum Switch Duty Cycle R T = 324k RT = 53.6k RT = 20k l Switch Current Limit (Note 4) 2 2.5 3 A Switch V CESAT ISW = 0.5A 0.10 V Switch Leakage Current V SW = 45V , FB = 1.3V 0.2 5 μA SHDN/UVLO Pin Threshold (VSD_SHDN) Shutdown 0.3 0.7 0.95 V SHDN/UVLO Pin Threshold (VSD_ UVLO) Rising 1.28 1.36 1.44 V SHDN/UVLO Pin Hysteresis Current SHDN = VSD_UVLO – 50mV SHDN = VSD_UVLO + 50mV 2.5 4 5.5 μA μA Soft-Start Current SS = 1V (Note 3) 11 μA PWM Input High Threshold 1V PWM Input Low Threshold 0.4 V

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 L T3599 is guaranteed to meet performance specifi cations from 0°C to 125°C junction temperature. Specifi cations over the –40°C to 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The L T3599I is guaranteed over the full –40°C to 125°C operating junction temperature range. Note 3: Current fl ows out of pin. Note 4: Current limit guaranteed by design and/or correlation to static test. Current limit is independent of duty cycle and is guaranteed by design. Note 5: TSSOP package only. ELECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 5V , VSHDN = 5V , unless otherwise noted. (Note 2) PARAMETER CONDITIONS MIN TYP MAX UNITS PWM Pin Bias Current PWM = 3.3V 0.1 2 μA SYNC Input High Threshold 1.7 V SYNC Input Low Threshold 0.8 V SYNC Pin Bias Current SYNC = 0V (Note 3) SYNC = 3.3V 0.1 μA μA VO_SW Switch Resistance 1000 Ω OPENLED Pull-Down Current PWM = 5V; LEDx < 0.2V, OPENLED = 0.3V 1 mA SHORTLED Pull-Down Current PWM = 5V; LEDx > (V OUT – 1.5V), SHORTLED = 0.3V 1 mA DISABLE4 Input High Threshold 1.15 V DISABLE4 Input Low Threshold 0.4 V

TYPICAL PERFORMANCE CHARACTERISTICS SHDN/UVLO Pin Turn-On Threshold (VSD_UVLO) SHDN/UVLO Pin (Hysteresis) Current V IN Current (Shutdown) VREF Switching Frequency Switching Frequency vs R T LED Current vs CTRL Pin Soft-Start Pin Current JUNCTION TEMPERATURE (°C) –50 SHDN/ UVLO (V) 1.40 1.35 05 0–25 25 75 100 125 1.25 1.30 1.45

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VIN CURRENT (nA) 150 200 250 500 350 100 400 450 300

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VIN = 30V VIN = 3V JUNCTION TEMPERATURE (°C) –50 05 0–25 25 75 100 125 JUNCTION TEMPERATURE (°C) –50 VREF (mV) 1240 1230 05 0–25 25 75 100 125 1210 1220 1250

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VIN = 30V VIN = 3V CTRL PIN VOLTAGE (V) LED CURRENT (mA) 120 1.0 100

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ISET = 13.3k JUNCTION TEMPERATURE (°C) –50 ISS (μA) (OUT OF PIN) 05 0–25 25 75 100 125

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RT (k) SWITCHING FREQUENCY (kHz)

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JUNCTION TEMPERATURE (°C) –50 SHDN/UVLO PIN CURRENT (μA) 05 0–25 25 75 100 125

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JUNCTION TEMPERATURE (°C) –50 SWITCHING FREQUENCY (MHz) 2.0 2.5 3.0 25 75

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1.5 1.0 –25 0 50 100 125 0.5 2.1MHz 0.2MHz 1MHz TA = 25°C unless otherwise specifi ed

VC Pin Active and Clamp Voltages LED Current vs PWM Duty Cycle Switch Saturation Voltage Switch Current Limit Feedback Pin Voltage LED Current vs Temperature LED Current Waveforms (0.1% PWM) (10ms Period) LED Current Waveforms (90% PWM) (10ms Period) VC (V) 1500 2000 2500 1000 500

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JUNCTION TEMPERATURE (°C) –50 05 0–25 25 75 100 125 PWM DUTY CYCLE (%) 0.01 LED CURRENT (mA) 100 11 00.1 100

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0.1 0.01 JUNCTION TEMPERATURE (°C) –50 LED CURRENT (mA) 100 05 0–25 25 75 100 125 101

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ISW (A) VCESAT (V) 0.10 0.20 0.30 0.5 1 2 1.5 0.40 0.05 0.15 0.25 0.35 2.5

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2μs/DIV PWM 5V/DIV SW 20V/DIV ILED1 50mA/DIV

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100μs/DIV PWM 5V/DIV SW 20V/DIV ILED1 50mA/DIV

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SWITCH CURRENT (A) 1.6 2.0 2.8 1.2 0.8 0.4 2.4

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JUNCTION TEMPERATURE (°C) –50 05 0–25 25 75 100 125 JUNCTION TEMPERATURE (°C) –50

1200 FEEDBACK PIN VOLTAGE (mV)

–25 25 100 125

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TYPICAL PERFORMANCE CHARACTERISTICSTA = 25°C unless otherwise specifi ed

LED1-4: LED String Output. Connect the bottom cathode of each LED string to these pins. DISABLE4: Allows Disabling Channel 4. Connect to VREF to disable channel 4. If channel 4 is disabled, the LED4 pin should be connected to the LED3 pin. Connect DISABLE4 to ground to allow operation of channel 4. SHORTLED: Indicates a high side short (LED pin shorted to V OUT). This is an open-collector output. OPENLED: Open LED Flag. An open-collector output when any LED string opens. ISET: Programs Led Current for Each String. A resistor to ground programs LED currents between 30mA and 120mA CTRL: LED Current Control. If the CTRL pin is not used, tie this pin to V REF. VC: Error Amplifi er Output Pin. Tie the external compensa- tion network to this pin. FB: Feedback Pin for Overvoltage Protection. Reference voltage is 1.223V . Connect the resistive divider tap here. Minimize trace area at FB. Set V OUT according to VOUT = 1.223(1 + R2/R1) when overvoltage protection occurs. TSET: An external resistor divider from V REF programs a decrease in LED current versus internal junction tempera- ture (setting temperature breakpoint). If the T SET pin is not used, tie this pin to VREF. SYNC: Frequency Synchronization Pin. This input allows for synchronizing the operating frequency to an external clock. The R T resistor should be chosen to program a switching frequency 20% slower than SYNC pulse frequency. This pin should be grounded if this feature is not used. PWM: Input Pin for PWM Dimming Control. Above 1V allows converter switching, and below 0.4V disables switching with V C pin level maintained. A PWM signal driving the PWM pin provides accurate dimming control. The PWM signal can be driven from 0V to 5V . If unused, the pin should be connected to V REF. RT: A Resistor to Ground Which Programs Switching Frequency Between 200kHz and 2.1MHz. For SYNC func- tion, choose the resistor to program a frequency 20% slower than the SYNC pulse frequency. Do not leave this pin open. SS: Soft-Start Pin. Place a soft-start capacitor here. Upon start-up, a 11μA current charges the capacitor . Use a larger capacitor for a slower start-up. V REF : Bandgap Voltage Reference. Internally set to 1.227V . This pin can supply up to 100μA. Can be used to program the CTRL pin voltage using resistor dividers to ground. GND: Analog Ground. Tie directly to local ground plane. Connect R T, ISET and T SET resistors between this local ground plane and their respective pins. SHDN/UVLO: The SHDN/UVLO pin has an accurate 1.4V threshold and can be used to program an undervoltage lockout (UVLO) threshold for system input supply using a resistor divider from supply to ground. A 4μA pin current hysteresis allows programming of undervoltage lockout (UVLO) hysteresis. 1.4V turns the part on and removes a 4μA sink current from the pin. SHDN/UVLO = 0V reduces V IN current < 0.1μA. SHDN/UVLO can be directly connected to VIN. Do not leave this pin open. VIN : Input Supply Pin. Must be locally bypassed with a capacitor to ground. SW: Switch Pin. This is the collector of the internal NPN power switch. Minimize the metal trace area connected to this pin to minimize EMI. V OUT: Output Pin. This pin provides power to all LEDs. VO_SW: Drain of an Internal PMOS. The internal PMOS disconnects the feedback resistors from the V OUT pin during shutdown and when the PWM pin is low. Exposed Pad: Ground. The ground for the IC should be soldered to a continuous copper ground plane under the L T3599 die.

Figure 1. Block Diagram

3599 F01

1.227 VREF

The L T3599 uses a constant-frequency, peak current mode control scheme to provide excellent line and load regula- tion. Operation can be best understood by referring to the Block Diagram in Figure 1. To turn on the L T3599, the V IN pin must exceed 3.1V and the SHDN/UVLO pin must exceed 1.4V . The SHDN/UVLO pin threshold allows programming of an undervoltage lockout (UVLO) threshold for the system input supply us- ing a simple resistor divider . A 4μA current fl ows into the SHDN/UVLO pin before the part turns on and is removed after the part turns on. This current hysteresis allows the programming of hysteresis for the UVLO threshold. See “Shutdown Pin and Programming Undervoltage Lockout” in the Applications Information section. For part switching, the PWM pin must exceed 1V (typical). For micropower shutdown, the SHDN/UVLO pin at 0V reduces V IN supply current to approximately ~0μA. L T3599 has a built-in boost converter which converts the input voltage to a higher output voltage for driving LEDs. The LED strings are connected to current sources where the current level is set with an external resistor on the I SET pin. The LED1 to LED4 voltages are monitored for output voltage regulation. During normal operation, when all LEDs are used, the lowest LED pin voltage (LED1 to LED4) is used to regulate the output voltage to ensure all LED strings have enough voltage to run the programmed current. If the user prefers only three strings, then LED string 4 can be disabled through the DISABLE4 pin and by connecting LED4 to any other LED pin. If the user prefers only two strings, then two pins are connected in parallel (i.e., LED1,2 and LED3,4 can be connected together in operation). The basic loop uses a pulse from an internal oscillator to set the SR latch and turn on the internal power NPN switch Q1. The signal at the noninverting input of the PWM comparator (A2) is proportional to the sum of the switch current and oscillator ramp. When this signal exceeds the V C voltage, the PWM comparator resets the latch. The switch is then turned off, causing the inductor current to lift the SW pin and turn on an external Schottky diode connected to the output. Inductor current fl ows via the Schottky diode charging the output capacitor . The switch is turned on again at the next reset cycle of the internal oscillator . During normal operation, the V C voltage controls the peak switch current limit and, hence, the inductor current available to the output LEDs. Dimming of the LEDs is accomplished by either PWM dim- ming or analog dimming. PWM dimming is achieved by pulsing the LED current using the PWM pin. For constant color LED dimming, the L T3599 provides up to a 3000:1 wide PWM dimming range by allowing the duty cycle of the PWM pin to be reduced from 100% to as low as 0.033%. When the PWM pin is low, switching is disabled and the error amplifi er is turned off so that it does not drive the V C pin. Also, all internal loads on the VC pin are disabled so that the state of the VC pin is maintained on the external compensation capacitor . This feature reduces transient recovery time. When the PWM input again transitions high, the peak switch current returns to the correct value. In applications where the user can sacrifi ce OPENLED, SHORTLED fault fl ag diagnostics, the dimming ratios can be as high as 3000:1. Analog dimming of LED currents is accomplished by varying the level of CTRL pin voltage. This method, however , changes LED color since dimming is achieved by changing LED current. For CTRL pin voltage less than 1V, LED current is defi ned as: IV R AmpsLED CTRL ISET = ⎛ ⎠⎟ ()• 1330 The L T3599 uses the FB pin to provide overvoltage protec- tion when all LED strings are open. There is an internal PMOS switch between V OUT and VO_SW that is controlled by the PWM signal. During the PWM off-period, this PMOS is turned off, allowing for higher dimming range and lower current during shutdown. A resistor divider is connected between the V O_SW pin and ground, which sets the overvoltage protection voltage. If the LED1-4 pin voltage is below 0.3V , the string is treated as an open LED string. As a result, an OPENLED fl ag is set. If a LED string is opened during regular operation, the output voltage will regulate to the optimum voltage for the remaining connected strings. If a short occurs between V OUT and any LED pin during operation, the L T3599 immediately turns off the shorted channel and sets a SHORTLED fl ag. Disabling the channel protects the L T3599 from high power thermal dissipation and ensures reliable operation.

core inductors should be used to obtain the best effi ciency. current greater than its rated value without damaging it. the inductor can reliably conduct. Table 1. Recommended Inductors designs. Table 2 lists some suggested manufacturers. their entire selection of ceramic parts. Table 2. Recommended Ceramic Capacitor Manufacturers output capacitor less, allowing for higher dimming range.

junction diodes) should not be used. Table 3. Suggested Diodes this resistance into account. voltage regulation given the programmed LED current. pin resistor can be selected from 11k to 44.2k. sponding programmed LED current. Table 4. RISET Value Selection for LED Current Figure 2. Overvoltage Protection Voltage Feedback Connections Figure 3. RISET Value Selection for LED Current

to be maintained over the entire dimming range. or PWM dimming (PWM pin duty cycle adjustment). Figure 4. LED Current vs CTRL Voltage Figure 5. LED Current vs CTRL Figure 6. LED Current Using PWM Dimming

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3599 F04

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resistance in the divider for the CTRL pin. is connected as closely as possible to the LED strings. Table 5. NTC Resistor Manufacturers/Distributors the effects of the NTC resistor overtemperature. with complete data over a wide range of temperatures. resistor by clicking on a link to the Murata catalog.

3599 F07

and the LED strings under worst-case conditions. to approximately 5% of the full LED current. Table 6. Resistor Values to Program Maximum IC Junction cycles to drive a large number of LEDs from a low supply. cycle and, hence, a greater number of LEDs to be driven. Table 7. Switching Frequency Figure 8. LED Current Derating

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at a fi xed delay after the rising edge of SYNC. control the turn off of the L T3599. switch current ramp up timing using a capacitor to ground. Figure 10. Programming Undervoltage Figure 9. Switching Frequency

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ramp up controls the ramp up of switch current limit. provide a 1V/ms ramp rate on the SS pin. duced to protect the inductor from high currents. Figure 11. Soft-Start Pin Timing Diagram thereby protecting the L T3599.

3599 F12

Figure 12. OPENLED and SHORTLED Connection

3599 F13

internal NPN devices serving as constant-current sources. switch DC loss, switch AC loss and input quiescent loss. similar voltage drop across the LEDs. paid to the PCB board layout and component placement. Figure 13. Recommended Component Placement PLANE UNDERNEATH THE DEVICE.

TOTAL LED CURRENT (mA) EFFICIENCY (%) 100 120 200 240 80 160 280 320

3599 TA02b

PVIN = 24V PVIN = 12V TYPICAL APPLICATIONS 12W LED Driver 1MHz Boost, 80mA per String, 10 LEDs per String Effi ciency PWM Dimming Range 1000:1 (10ms Period) 10μs/DIV PWM 5V/DIV ILED TOTAL 200mA/DIV

3599 TA02c

3.3μF 25V 47nF C1: MURATA GRM21BR71E335K C2: MURATA GRM31CR71H475K D1: DIODES INC. DFLS240 L1: VISHAY IHLP2020BZER100M01 10μH 4.7μF 50V 100pF C C 10nF 3599 TA02a L T3599 VO_SW FBOPENLED SHORTLED PWM SHDN/UVLO RT SYNC PWM 80mA PER STRING CTRL VREF TSET LED1 LED2 LED3 LED4 VOUTSW VIN VCSS GNDISET R10 R11 31.6k VIN VIN 3.1V TO 5.5V VIN 16.5k 53.6k 100k DISABLE4 100k 31.6k 33.2k 52.3k 80.6k 200k PVIN 8V TO 24V 1μF 6.3V 220pF

400kHz Boost, T wo LED Strings, 200mA per String, 8 LEDs per String 3.3μF 25V 47nF 22μH D1

3599 TA03a

VO_SW FBOPENLED SHORTLED PWM SHDN/UVLO RT SYNC PWM 200mA PER STRING CTRL VREF TSET LED1 LED2 LED3 LED4 VOUTSWVIN VCSS GNDISET VIN VIN 3.1V TO 5.5V VIN 13.3k 143k 100kR4 100k DISABLE4 32.4k 32.4k 52.3k 80.6k 200k RC 1k 100pF CC 22nF R10 R11 39.2k 220pF 4.7μF 50V

8 LEDs/

1μF 6.3V C1: MURATA GRM21BR71E335K C2: MURATA GRM31CR71H475K D1: DIODES INC. DFLS240 L1: VISHAY IHLP2525CZER220M11

SEPIC (Survives Output Short to Ground) 300kHz, Three Strings, 100mA per String, 6 LEDs per String RC 4.99k 3.3μF 25V 47nF 22μH 22μH 4.7μF 50V 4.7μF 25V 1μF 25V 100pF C C 4.7nF 3599 TA04a L T3599 VO_SW FBOPENLED SHORTLED PWM SHDN/UVLO RT SYNC PWM 100mA PER STRING

6 LEDs/

10Ω R11 49.9k VIN VIN 13.3k 200k 100kR4 100k DISABLE4R7 52.3k 80.6k 200k 31.6k 33.2k 220pF VIN 3.1V TO 5.5V PVIN 8V TO 16V 1μF 6.3V C1: MURATA GRM21BR71E335K C2: MURATA GRM31CR71H475K D1: DIODES INC. B360A L1, L2: VISHAY IHLP2525CZER220M11

2MHz Boost, Three Strings, 100mA per String, 7 LEDs per String 3.3μF 25V 47nF 4.7μH D1

3599 TA05a

VO_SW FBOPENLED SHORTLED PWM SHDN/UVLO RT SYNC PWM 100mA PER STRING CTRL VREF TSET LED1 LED2 LED3 LED4 VOUTSWVIN VCSS GNDISET VIN VIN 13.3k 21.5k 100kR4 100k DISABLE4R7 52.3k 80.6k 200k 31.6k 33.2k RC 4.02k 100pF CC 10nF R10 R11 43.2k 220pF 4.7μF 50V

7 LEDs/

3.1V TO 5.5V PVIN 8V TO 16V 1μF 6.3V C1: MURATA GRM21BR71E335K C2: MURATA GRM31CR71H475K D1: DIODES INC. DFLS240 L1: SUMIDA CDRH4D22HPNP-4R7N

2.1 MHz Boost, Four Strings, 80mA per String, 7 LEDs per String

3.3μF 25V 47nF 4.7μH D1 4.7μF 50V C C 10nF 16.5k

3599 TA06a

VO_SW FBOPENLED SHORTLED PWM SHDN/UVLO RT SYNC PWM 80mA PER STRING CTRL VREF TSET LED1 LED2 LED3 LED4 VOUTSWVIN VC SS GNDISET R10 R11 43.2k PVIN 9V TO 16V VIN VIN 3.1V TO 5.5V VIN 20k 100k DISABLE4 100k 52.3k 80.6k 200k 32.4k 32.4k 1μF 6.3V 220pF C1: MURATA GRM21BR71E335K C2: MURATA GRM31CR71H475K D1: DIODES INC. DFLS240 L1: SUMIDA CDRH4D22HPNP-4R7N PWM 5V/DIV ILED TOTAL 200mA/DIV 10μs/DIV

3599 TA07

PWM Dimming 3000:1 (10ms Period)

28-Lead Plastic TSSOP (4.4mm) (Reference L TC DWG # 05-08-1663) Exposed Pad Variation EB FE28 (EB) TSSOP 0204 0.09 – 0.20 (.0035 – .0079) 0° – 8° 0.25 REF 0.50 – 0.75 (.020 – .030) 4.30 – 4.50* (.169 – .177) 13 4 5 6 7 8 91 0 11 12 13 14 192022 21 15 1618 17 9.60 – 9.80* (.378 – .386) 4.75 (.187) 2.74 (.108) 28 2726 25 24 23 1.20 (.047) MAX 0.05 – 0.15 (.002 – .006) 0.65 (.0256) BSC 0.195 – 0.30 (.0077 – .0118) TYP 2RECOMMENDED SOLDER PAD LAYOUT EXPOSED PAD HEAT SINK ON BOTTOM OF PACKAGE0.45 ±0.05

0.65 BSC

4.50 ±0.10 6.60 ±0.10 1.05 ±0.10 4.75 (.187) 2.74 (.108) MILLIMETERS (INCHES) *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.150mm (.006") PER SIDE NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS 2. DIMENSIONS ARE IN 3. DRAWING NOT TO SCALE SEE NOTE 4 4. RECOMMENDED MINIMUM PCB METAL SIZE FOR EXPOSED PAD ATTACHMENT 6.40 (.252) 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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. PACKAGE DESCRIPTION 5.00 ± 0.10 (4 SIDES) NOTE: 1. DRAWING PROPOSED TO BE A JEDEC PACKAGE OUTLINE M0-220 VARIATION WHHD-(X) (TO BE APPROVED) 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 0.20mm 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 PIN 1 TOP MARK (NOTE 6) 0.40 ± 0.10 BOTTOM VIEW—EXPOSED PAD

3.50 REF

(4-SIDES) 3.45 ± 0.10 3.45 ± 0.10 0.75 ± 0.05 R = 0.115 TYP 0.25 ± 0.05 (UH32) QFN

0406 REV D

0.50 BSC

0.200 REF

0.00 – 0.05 0.70 ±0.05 (4 SIDES) 4.10 ±0.05 5.50 ±0.05 0.25 ± 0.05 PACKAGE OUTLINE RECOMMENDED SOLDER PAD LAYOUT APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED PIN 1 NOTCH R = 0.30 TYP OR 0.35 × 45° CHAMFER R = 0.05 TYP 3.45 ± 0.05 3.45 ± 0.05 32-Lead Plastic QFN (5mm × 5mm) (Reference L TC DWG # 05-08-1693 Rev D)

Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear .com © LINEAR TECHNOLOGY CORPORATION 2009 LT 0109 • PRINTED IN USA RELATED PARTS PART NUMBER DESCRIPTION COMMENTS L T3463/ L T3463A Dual Output, Boost/Inverter , 250mA ISW, Constant Off-Time, High Effi ciency Step-Up DC/DC Converter with Integrated Schottkys V IN: 2.3V to 15V , VOUT(MAX) = ±40V , IQ = 40μA, ISD < 1μA, 3mm × 3mm L T3466/ L T3466-1 Dual Constant Current, 2MHz, High Effi ciency White LED Boost Regulator with Integrated Schottky Diode VIN: 2.7V to 24V , VOUT(MAX) = 40V , IQ = 5μA, ISD < 16μA, 3mm × 3mm L T3474 36V , 1A (I LED), 2MHz, Step-Down LED Driver V IN: 4V to 36V , VOUT(MAX) = 13.5V , T rue Color PWM Dimming = 400:1, ISD < 1μA, TSSOP-16E Package L T3475 Dual 1.5A (I LED), 36V , 2MHz, Step-Down LED Driver V IN: 4V to 36V , VOUT(MAX) = 13.5V , T rue Color PWM Dimming = 3000:1, ISD < 1μA, TSSOP-20E Package L T3476 Quad Output 1.5A, 2MHz High Current LED Driver with 1000:1 Dimming VIN: 2.8V to 16V , VOUT(MAX) = 36V , T rue Color PWM Dimming = 1000:1, ISD < 3μA, 5mm × 7mm QFN-10 Package L T3477 3A, 42V , 3MHz Boost, Buck-Boost, Buck LED Driver V IN: 2.5V to 25V , VOUT(MAX) = 40V , Dimming = Analog/PWM, ISD < 1μA, QFN and TSSOP-20E Packages L T3478/ L T3478-1 High Current LED Driver V IN: 2.8V to 36V , VOUT(MAX) = 42V , T rue Color PWM Dimming = 3000:1, ISD < 10μA, TSSOP-16E Package L T3486 Dual 1.3A, 2MHz High Current LED Driver V IN: 2.5V to 24V , VOUT(MAX) = 36V , T rue Color PWM Dimming = 1000:1, ISD < 1μA, 5mm × 3mm DFN and TSSOP-16E Packages L T3496 45V , 2.1MHz 3-Channel (I LED = 1A) Full Featured LED Driver VIN: 3V to 30V (40VMAX), VOUT(MAX) = 45V , T rue Color PWM Dimming = 3000:1, ISD < 1μA, 4mm × 5mm QFN-28 Package L T3497 Dual 2.3MHz, Full Function LED Driver with Integrated Schottkys and 250:1 T rue Color PWM Dimming VIN: 2.5V to 10V , VOUT(MAX) = 32V , IQ = 6mA, ISD < 12μA, 2mm × 3mm L T3498 2.3MHz, 20mA LED Driver and OLED Driver with Integrated Schottkys a ??? VIN: 2.5V to 12V , VOUT(MAX) = 32V , IQ = 1.65mA, ISD < 9μA, 2mm × 3mm L T3518/ L T3517 2.3A/1.3A 45V , 2.5MHz Full Featured LED Driver with T rue Color PWM Dimming VIN: 3V to 30V (40VMAX), VOUT(MAX) = 42V , T rue Color PWM Dimming = 3000:1, ISD < 5μA, 4mm × 4mm QFN-16 Package L T3590 48V Buck Mode LED Driver V IN: 4.5V to 55V , VOUT(MAX) = 5V , IQ = 700μA, ISD < 15μA, 2mm × 2mm DFN-6 and SC70 Packages L T3591 Constant Current, 1MHz, High Effi ciency White LED Boost Regulator with Integrated Schottky Diode and 80:1 T rue Color PWM Dimming V IN: 2.5V to 12V , VOUT(MAX) = 40V , IQ = 4mA, ISD < 9μA, 2mm × 3mm L T3595 45V , 2.5MHz 16-Channel Full Featured LED Driver V IN: 4.5V to 45V , VOUT(MAX) = 45V , T rue Color PWM Dimming = 5000:1, ISD < 1μA, 5mm × 9mm QFN-56 Package L T3598 44V , 1.5A, 2.5MHz Boost 6-Channel LED Driver V IN: 3V to 30V , VOUT(MAX) = 44V , T rue Color PWM Dimming = 3000:1, ISD < 1μA, 4mm × 4mm QFN-24 Package