3595

LT3595 LINER

Document overview

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Technical content

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. True Color PWM is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

16 Channel

The LT®3595 is a high performance LED Driver designed to drive sixteen independent channels of up to 10 LEDs at currents up to 50mA. Series connection of the LEDs provides identical LED currents resulting in uniform bright- ness. Power switches, Schottky diodes, and compensation components are all internal, providing a small converter footprint and lower component cost. The high 2MHz switching frequency permits the use of tiny, low profi le inductors and capacitors. A fi xed frequency, current mode architecture results in stable operation over a wide range of supply and output voltage. A single external resistor sets the LED current for all sixteen channels, and dimming is then controlled for each channel by pulse width modulating the individual PWM pins. Rela- tive current matching among the sixteen drivers is 8% and the PWM dimming range is 5000:1. The part is available in a 5mm × 9mm × 0.75mm 56-pin QFN package. 16-Channel LED Driver (Three LEDs per Channel), 20mA Current ■ 4.5V to 45V Input Supply Range ■ Up to 50mA LED Current per Channel ■ 100mA, 45V Internal Switches ■ 8% Relative LED Current Match at 20mA ■ 16 Independent LED Channels ■ 5000:1 True Color PWM TM Dimming Range ■ LEDs Disconnected in Shutdown ■ Internal Schottky Diodes ■ Low Quiescent Current ■ 2MHz Switching Frequency ■ R SET Pin Sets Master LED Current ■ Typical Effi ciency: 92% ■ Open LED Detection and Thermal Protection ■ 56-Pin 5mm × 9mm × 0.75mm QFN Package ■ LED Video Billboards ■ LCD Televisions ■ Stadium and Advertising Displays 5000:1 PWM Dimming at 100HzVIN 15V TO 45V LED BRIGHTNESS CONTROL VCC 3V TO 5.5V VCC 0.47μF 10μF 10μF 100k 75.0k

3595 TA01

V CC PWM9 PWM10 PWM11 PWM12 PWM13 PWM14 PWM15 PWM16 GND R SET L1 SW1 SW2 L4 SW3 SW7L3 SW4 L5 L6 SW5 SW6L2 L7 SW8 L8 L16 SW16 SW15 V IN L13SW14 V IN SW10L14 SW13 L12 L11 SW12 SW11L15 L10 SW9 L9 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH SHDN LT3595 LED BRIGHT- NESS CONTROL 400ns/DIV ILED 10mA/DIV ISW 20mA/DIV VPWM 5V/DIV

3595 TA01b

VIN = 15V

3 LEDS AT 20mA

T = 10ms TON = 2μs

PIN CONFIGURATIONABSOLUTE MAXIMUM RATINGS Operating Junction Temperature Range (Note 1) 19 20 21 22 TOP VIEW UHH PACKAGE 56-LEAD (5mm × 9mm) PLASTIC QFN 23 24 25 26 27 28 56 55 54 53 52 51 50 49 48 47

1 L16

V IN SW14 L14 SW13 L13 L12 SW12 L11 SW11 VIN SW10 L10 SW9 SW1 SW2 NC SW3 SW4 SW5 SW6 NC SW7 SW8 PWM16 PWM15 PWM14 PWM13 V CC RSET PWM4 PWM3 PWM2 PWM1 PWM9 PWM10 PWM11 PWM12 OPENLED SHDN PWM5 PWM6 PWM7 PWM8 TJMAX = 125°C, θJA = 31°C/W, θJC = 0.5°C/W EXPOSED PAD (PIN 57) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT3595EUHH#PBF LT3595EUHH#TRPBF 3595 56-Lead (5mm × 9mm) Plastic QFN –40°C to 85°C Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. Consult LTC 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/

ELECTRICAL CHARACTERISTICS

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. PARAMETER CONDITIONS MIN TYP MAX UNITS VIN Operating Voltage 4.5 V VCC Operating Voltage 3 5.5 V VCC Input Under Voltage Lockout 2.6 2.9 V IVIN Quiescent Current ON, No Switching V IN = 45V 0.25 mA IVIN Quiescent Current in Shutdown V IN = 45V, ⎯S⎯H⎯D⎯N = 0V 15 40 μA IVCC Quiescent Current ON, No Switching V CC = 3.3V 17 mA IVCC Quiescent Current in Shutdown V CC = 3.3V, ⎯S⎯H⎯D⎯N = 0V 3 10 μA IL1-16 Output Current Accuracy R SET = 75.0kΩ 18.4 20 21.6 mA Switching Frequency 1 . 622 . 4M H z Maximum Duty Cycle ● 78 83 % Switch Current Limit ● 90 120 150 mA Switch VCESAT ISW1-16 = 50mA 450 mV Switch Leakage Current VSW1-16 = 45V 0.1 6 μA Schottky Forward Drop I SCHOTTKY = 50mA 0.8 V Schottky Leakage Current V IN = 45V, VSW1-16 = 0.7V, ⎯S⎯H⎯D⎯N = 0V 0.1 4 μA ⎯S⎯H⎯D⎯N, PWM1-16 Input Low Voltage 0.4 V ⎯S⎯H⎯D⎯N, PWM1-16 Input High Voltage 1.6 V ⎯S⎯H⎯D⎯N Pin Bias Current ⎯S⎯H⎯D⎯N = 3.3V 35 μA PWM1-16 Pin Bias Current PWM1-16 = 3.3V 0.1 1 μA ⎯O⎯P⎯E⎯N⎯L⎯E⎯D Pin Voltage V CC = 3.3V, I⎯O⎯P⎯E⎯N⎯L⎯E⎯D = 200μA 0.12 V ⎯O⎯P⎯E⎯N⎯L⎯E⎯D Pin Input Leakage Current ⎯O⎯P⎯E⎯N⎯L⎯E⎯D = 3.3V 0.1 1 μA The ● denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C, VIN = 45V, VCC = 3.3V, PWM = ⎯S⎯H⎯D⎯N = ⎯O⎯P⎯E⎯N⎯L⎯E⎯D = 3.3V, RSET = 75kΩ, GND = 0V, unless otherwise noted. Note 2: The LT3595 is guaranteed to meet performance specifi cations from 0°C to 85°C junction temperature. Specifi cations over the –40°C to 85°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls.

RSET RESISTANCE (kΩ) LED CURRENT (mA) 50 150 75 100 125

3595 G05

DUTY CYCLE (%) 0.01 LED CURRENT (mA) 100 0.1 0.01 0.001 0.1 1 10 100

3595 G04

VIN = 45V

10 LEDS AT 20mA

PWM FREQUENCY = 100Hz TYPICAL PERFORMANCE CHARACTERISTICS Switching Waveforms PWM Dimming Waveforms (1000:1) LED Current vs PWM Duty Cycle Wide Dimming Range (5000:1) LED Current vs RSET Resistance VIN Quiescent Current VCC Quiescent Current ⎯S⎯H⎯D⎯N Pin Bias Current PWM Dimming Waveforms (10:1) VIN (V) VIN CURRENT (mA) 1.2 1.6 2.0 0.8 0.4 10 20 30

3595 G06

T = 25°C T = 125°C T = – 40°C 400ns/DIV

10 LEDS

5 LEDS

VIN = 45V ILED = 20mA 2μs/DIV ILED 20mA/DIV IL 20mA/DIV PWM 5V/DIV

3595 G02

VIN = 40V PWM FREQUENCY = 100Hz TON = 10μs 2ms/DIV ILED 20mA/DIV IL 20mA/DIV PWM 5V/DIV

3595 G03

VIN = 40V PWM FREQUENCY = 100Hz TON = 1ms VCC (V) VCC CURRENT (mA) 2 4 5 1 3 6 7

3595 F07

T = 125°C T = –40 °C T = 25°C VCC = 3.3V 100 1 234 56

3595 F08

T = 125°C T = –40 °C ISHDN (μA) T = 25°C VSHDN (V)

Current Limit vs Temperature TYPICAL PERFORMANCE CHARACTERISTICS Switching Frequency vs Temperature Schottky Leakage Current vs Temperature Switch Saturation Voltage (VCESAT) Schottky Forward Voltage Drop Transient Response ⎯O⎯P⎯E⎯N⎯L⎯E⎯D Waveforms TEMPERATURE (°C) –50 130 140 150 25 75 120 110 –25 0 50 100 125 100 CURRENT LIMIT (mA)

3595 G09

TEMPERATURE (°C) –50 2.0 2.2 2.1 2.3 2.4 25 75 1.9 1.8 –25 0 50 100 125 1.7 1.6 SWITCHING FREQUENCY (MHz)

3595 G10

TEMPERATURE (°C) –50 0.8 1.0 1.4 25 75 0.6 0.4 –25 0 50 100 125 0.2 1.2 SCHOTTKY LEAKAGE CURRENT (μA)

3595 G11

VIN = 45V VIN = 24V VIN = 4.5V SWITCH CURRENT (mA) 500 600 700 400 300 20 40 60 100 200 100 SWITCH SATURATION VOLTAGE (mV) T = 125°C T = –40 °C T = 25°C SCHOTTKY FORWARD DROP (V) SCHOTTKY FORWARD CURRENT (mA) 100 0.8 0.2 0.4 0.6 1

3595 G13

T = 125°C T = – 40°C T = 25°C 100μs/DIV VSW 50V/DIV ISW 50mA/DIV ILED 20mA/DIV

3595 G14

VIN = 45V 20μs/DIV VSW CH 1 50V/DIV ILED CH 2 20mA/DIV ILED CH 1 20mA/DIV

3595 G15

VIN = 45V

38, 40, 44, 46): LED Pins. Connection point for the anode of the highest LED in each string. SW1-16 (Pins 2, 4, 6, 8, 11, 13, 15, 17, 30, 32, 34, 36, 39, 41, 43, 45): Switch Pins. Minimize trace area at these pins to minimize EMI. Connect the inductors to these pins. V IN (Pins 5, 14): 4.5V to 45V Input Supply Pin. Must be locally bypassed. Both V IN pins must be tied together. PWM1-16 (Pins 19-22, 25-28, 47-50, 53-56): Input Pin for LED Dimming Function. The rising edge of each channel must be synchronized. ⎯O⎯P⎯E⎯N⎯L⎯E⎯D (Pin 23): Open Collector Output for Reporting Faults. If any channel experiences an open LED connec- tion, the ⎯O⎯P⎯E⎯N⎯L⎯E⎯D pin is pulled low. ⎯S⎯H⎯D⎯N (Pin 24): Shutdown. Tie to 1.6V or greater to enable the device. Tie below 0.4V to turn off the device. NC (Pins 33, 42): No Connect. Connect these pins to ground. RSET (Pin 51): External Resistor to Set the Master LED Current. The LED current is equal to: I V RLED SET = 12 1 1240.  where RSET is the value of the external resistor. Use a kelvin for ground metal. VCC (Pin 52): 3.3V Input Supply. Must be locally by- passed. Exposed Pad (Pin 57): Ground. The Exposed Pad must be soldered to PCB. Use wide metal from backtab to the grounds of the input capacitors on V CC and VIN.

R S V/I Q 2MHz OSCILLATOR Σ CONTROL ISNS

1 CHANNEL

3.3V L1-16 SW1-16 OPENLED GND VIN 10μF RSET VCC SHDN RSET L1-16 100μH COUT1-16 0.47μF CIN 10μF VINPWM1-16 REF PWM

The LT3595 uses a constant-frequency, current mode control scheme to provide excellent line and load regula- tion. Operation is best understood by referring to the Block Diagram. The oscillator, V-I converter and internal regulator are shared by the sixteen converters. The control circuitry, power switches, PWM comparators and dimming control (DFC) are identical for all converters. The LT3595 enters shutdown mode when the ⎯S⎯H⎯D⎯N pin is lower than 400mV. If the ⎯S⎯H⎯D⎯N pin is above 1.6V, then the LT3595 turns on. At the start of each oscillator cycle, the power switch is turned on. Current ramps up through the output capacitor, the inductor, and the switch to ground. When the voltage across the output capacitor is larger than the LEDs’ forward voltage, current fl ows through the LEDs. When the switch is on, 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 compara- tor. When this voltage exceeds the level at the negative input of the PWM comparator, the PWM logic turns off the power switch. The level at the negative input of the PWM comparator is set by the error amplifi er output. This voltage is set by the LED current and the bandgap refer- ence. In this manner, the error amplifi er sets the correct peak current level in the inductor to keep the LED output current in regulation. The external R SET resistor is used to program the LED current from 10mA to 50mA. Input Voltage Range The minimum input voltage required to generate a specifi c output voltage in an LT3595 application is limited by its 4.5V input voltage or by its maximum duty cycle. The duty cycle is the fraction of time that the internal switch is on divided by the total period. It is determined by the input voltage and the voltage across the LEDs: DC VV VV V LED D VIN CESAT D = + where VLED is the voltage drop across the LEDs, V D is the Schottky forward drop, and V CESAT is the saturation voltage of the internal switch. This leads to a minimum input voltage of: V VV DC VVIN MIN LED D MAX CESAT D() = + +− where DCMAX is the minimum rating of maximum duty cycle. The maximum input voltage is limited by the absolute maximum rating of 45V. Pulse-Skipping At low duty cycles, the LT3595 may enter pulse-skipping mode. Low duty cycle occurs at higher input voltages and lower LED count. The LT3595 can drive currents without pulse-skipping provided the voltage across the LED string is greater than 15% of the input supply voltage. If the current decreases to the point that the LED voltage is less than 15% of the input supply, the device may begin skipping pulses. This will result in some low frequency ripple, although the LED current remains regulated on an average basis down to 10mA.

Figure 1. Switching Waveforms Table 1. Inductor Manufacturers Figure 2. Effi ciency Comparison of Different Inductors

3595 F01

10 LEDS AT 10mA

3595 F02

Table 2. Recommended Output Capacitor Values (VLED = 3.5V) Table 3. Recommended Ceramic Capacitor Manufacturers on their entire selection of ceramic parts. rent and their required resistor values are listed in Table 4. precision resistors are preferred (1% is recommended). The maximum allowed resistor value is 150k. Table 4. LED Current vs RSET Resistance

Figure 3. Timing Diagram for Multi-Channel Modulation 100Hz). Therefore, the maximum dimming ratio is 5000:1. modulated LED current is 2μA.

3595 F03

30W LED Driver for 160 LEDs (16 Strings, 10 LEDs per String) at 50mA Conversion Effi ciency TYPICAL APPLICATIONS VIN 45V 0.47μF 10μF

3595 TA02

L1 SW1 SW2 L4 SW3 SW7L3 SW4 L5 L6 SW5 SW6L2 L7 SW8 L8 L16 SW16 SW15 V IN L13SW14 V IN SW10L14 SW13 L12 L11 SW12 SW11L15 L10 SW9 L9 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH LT3595 LED BRIGHTNESS CONTROL 3V TO 5.5V VCC 10μF 100k 30.1k OPENLED PWM1 PWM2 PWM3 PWM4 PWM5 PWM6 PWM7 PWM8 V CC PWM9 PWM10 PWM11 PWM12 PWM13 PWM14 PWM15 PWM16 GND R SET LED BRIGHTNESS CONTROL SHDN 5000:1 PWM Dimming at 100Hz ILED (mA) EFFICIENCY (mA) 100 20 30 40 50

3595 TA02b

3595 TA02c

10 LEDS AT 40mA

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 56-Lead Plastic QFN (5mm × 9mm) (Reference LTC DWG # 05-08-1727 Rev A) 5.00 ± 0.10 (2 SIDES) NOTE: 1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS PIN 1 TOP MARK (SEE NOTE 6) BOTTOM VIEW—EXPOSED PAD 3.45 ±0.10 7.13 ±0.10 6.80 REF9.00 ± 0.10 (2 SIDES) 0.75 ± 0.05 R = 0.115 TYP 0.20 ± 0.05 (UH) QFN 0406 REV A 0.40 BSC0.200 REF

0.200 REF

0.00 – 0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED

3.60 REF

0.40 ±0.10 0.70 ± 0.05

0.40 BSC

6.80 REF (2 SIDES)

(2 SIDES) 4.10 ± 0.05 (2 SIDES) 5.50 ± 0.05 (2 SIDES) 7.13 ±0.05 3.45 ±0.05 8.10 ± 0.05 (2 SIDES) 9.50 ± 0.05 (2 SIDES) 0.20 ± 0.05 PACKAGE OUTLINE 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 NOTCH R = 0.30 TYP OR 0.35 × 45° CHAMFER

Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2007 LT 0807 • PRINTED IN USA RELATED PARTS TYPICAL APPLICATIONS PART NUMBER DESCRIPTION COMMENTS LT3463/ LT3463A Dual Output, Boost/Inverter, 250mA ISW, Constant Off-Time, High Effi ciency Step-Up DC/DC Converter with Integrated Schottky Diodes VIN: 2.3V to 15V, VOUT(MAX) = ±40V, IQ = 40μA, ISD < 1μA, 3mm × 3mm DFN-10 Package LT3465/ LT3465A Constant-Current, 1.2MHz/2.7MHz, High Effi ciency White LED Boost Regulator with Integrated Schottky Diode VIN: 2.7V to 16V, VOUT(MAX) = 34V, IQ = 1.9mA, ISD < 1μA, ThinSOTTM Package LT3466/ LT3466-1 Dual Constant-Current, 2MHz, High Effi ciency White LED Boost Regulator with Integrated Schottky Diode VIN: 2.7V to 24V, VOUT(MAX) = 40V, IQ = 5mA, ISD < 16μA, 3mm × 3mm DFN-10 Package LT3474 36V, 1A (I LED), 2MHz, Step-Down LED Driver V IN: 4V to 36V, VOUT(MAX) = 13.5V, 400:1 True Color PWMTM, ISD < 1μA, TSSOP-16E Package LT3475 Dual 1.5A (I LED), 36V, 2MHz, Step-Down LED Driver V IN: 4V to 36V, VOUT(MAX) = 13.5V, 3000:1 True Color PWM, ISD < 1μA, TSSOP-20E Package LT3476 Quad Output 1.5A, 2MHz High Current LED Driver with 1000:1 Dimming VIN: 2.8V to 16V, VOUT(MAX) = 36V, 1000:1 True Color PWM, ISD < 10μA, 5mm × 7mm QFN-10 Package LT3486 Dual 1.3A , 2MHz High Current LED Driver V IN: 2.5V to 24V, VOUT(MAX) = 36V, 1000:1 True Color PWM, ISD < 1μA, 5mm × 3mm DFN and TSSOP-16E Packages LT3491 Constant-Current, 2.3MHz, High Effi ciency White LED Boost Regulator with Integrated Schottky Diode VIN: 2.5V to 12V, VOUT(MAX) = 27V, IQ = 2.6mA, ISD < 8μA, 2mm × 2mm DFN-6 and SC70 Packages LT3497 Dual 2.3MHz, Full Function LED Driver with Integrated Schottky Diodes and 250:1 True Color PWM Dimming VIN: 2.5V to 10V, VOUT(MAX) = 32V, IQ = 6μA, ISD < 12μA, 3mm × 2mm DFN-10 Package LT3498 2.3MHz, 20mA LED Driver and OLED Driver with Integrated Schottky Diodes VIN: 2.5V to 12V, VOUT(MAX) = 32V, IQ = 1.65mA, ISD < 9μA, 3mm × 2mm DFN-12 Package LT3517/LT3518 2.3A/1.3A 45V, 2.5MHz Full Featured LED Driver with True Color PWM Dimming VIN: 3V to 30V/40V, VOUT(MAX) = 42V, 3000:1 True Color PWM, ISD < 5μA, 4mm × 4mm QFN-16 Package LT3590 48V Buck Mode LED Driver V IN: 4.5V to 55V, VOUT(MAX) = 5V, IQ = 700μA, ISD < 15μA, 2mm × 2mm DFN-16 and SC70 Packages LT3591 Constant-Current, 1MHz, High Effi ciency White LED Boost Regulator with Integrated Schottky Diode and 80:1 True Color PWM Dimming VIN: 2.5V to 12V, VOUT(MAX) = 40V, IQ = 4mA, ISD < 9μA, 3mm × 2mm DFN-8 Package True Color PWM and ThinSOT are trademarks of Linear Technology Corporation. 5000:1 PWM Dimming at 100Hz16-Channel LED Driver (Three LEDs per Channel), 20mA Current VIN 15V TO 45V 0.47μF 10μF

3595 TA03

L1 SW1 SW2 L4 SW3 SW7L3 SW4 L5 L6 SW5 SW6L2 L7 SW8 L8 L16 SW16 SW15 V IN L13SW14 V IN SW10L14 SW13 L12 L11 SW12 SW11L15 L10 SW9 L9 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH 100μH LT3595 LED BRIGHTNESS CONTROL 3V TO 5.5V VCC 10μF 100k 75.0k OPENLED PWM1 PWM2 PWM3 PWM4 PWM5 PWM6 PWM7 PWM8 V CC PWM9 PWM10 PWM11 PWM12 PWM13 PWM14 PWM15 PWM16 GND R SET LED BRIGHT- NESS CONTROL SHDN 400ns/DIV ILED 10mA/DIV ISW 20mA/DIV VPWM 5V/DIV

3595 TA03b

VIN = 15V T = 10ms TON = 2μs