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FEATURES
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LT3595A 16 Channel Buck Mode LED Driver DESCRIPTION
The LT®3595A 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 brightness. 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 profile inductors and capacitors. A fixed 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. LED current accuracy is 7%, channel-to-channel current matching is ±4% and the PWM dimming range is 5000:1. The part is available in a 5mm × 9mm × 0.75mm 56-pin QFN package.
L, 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.
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4.5V to 45V Input Supply Range Up to 50mA LED Current per Channel 100mA, 45V Internal Switches Improvements vs LT3595 Pinout Allows 1-Sided PCB Layout Higher Maximum Switch Duty Cycle LED Current Accuracy (7% vs 8%) ±4% LED Current Matching 16 Independent LED Channels 5000:1 True Color PWMTM Dimming Range LEDs Disconnected in Shutdown Internal Schottky Diodes 2MHz Switching Frequency RSET Pin Sets Master LED Current Typical Efficiency: 92% Open LED Detection and Thermal Protection 56-Pin 5mm × 9mm × 0.75mm QFN Package
APPLICATIONS
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LED Video Billboards LCD Televisions Stadium and Advertising Displays
TYPICAL APPLICATION
16-Channel LED Driver (Three LEDs per Channel), 20mA Current
VIN 15V TO 45V 0.47μF 0.47μF 0.47μF 0.47μF 0.47μF 0.47μF 0.47μF 0.47μF VPWM 5V/DIV
5000:1 PWM Dimming at 100Hz
10μF
100μH
100μH
100μH
100μH
100μH
100μH
100μH
VCC 100k
100μH
LED BRIGHTNESS CONTROL
100μH
100μH
100μH
100μH
100μH
100μH
100μH
0.47μF
0.47μF
0.47μF
0.47μF
0.47μF
0.47μF
0.47μF
100μH
10μF
0.47μF
3595A TA01
75.0k
VCC 3V TO 5.5V
L1 SW1 OPENLED PWM1 PWM2 PWM3 PWM4 PWM5 PWM6 PWM7 PWM8 SHDN VCC L16 SW16
L2
SW2
SW3
L3
SW4
L4
L5
SW5
L6
SW6
SW7
L7
SW8
L8
ISW 20mA/DIV
LT3595A
L15 SW15 VIN SW14 L14
SW13
L13
L12
SW12 L11 SW11 VIN SW10 L10
PWM9 PWM10 PWM11 PWM12 PWM13 PWM14 PWM15 PWM16 GND RSET SW9 L9
LED BRIGHTNESS CONTROL
ILED 10mA/DIV 400ns/DIV VIN = 15V 3 LEDS AT 20mA T = 10ms tON = 2μs
3595A TA01b
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LT3595A PIN CONFIGURATION
TOP VIEW PWM16 PWM15 PWM14 PWM13 PWM4 PWM3 PWM2 PWM7 PWM1 46 L1 45 SW1 44 L2 43 SW2 42 GND 41 SW3 40 L3 39 SW4 57 38 L4 37 L5 36 SW5 35 L6 34 SW6 33 VIN 32 SW7 31 L7 30 SW8 29 L8 19 20 21 22 23 24 25 26 27 28 PWM9 PWM10 PWM11 PWM12 PWM5 PWM6 OPENLED PWM8 SHDN RSET VCC
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Input Voltage (VIN) ....................................................45V L1-16 Voltage ...........................................................45V Supply Voltage (VCC) ..................................................6V RSET, OPENLED, PWM1-16, SHDN Voltage.................6V Operating Junction Temperature Range (Note 2) .............................................–40°C to 125°C Storage Temperature Range...................–65°C to 125°C
56 55 54 53 52 51 50 49 48 47 L16 1 SW16 2 L15 3 SW15 4 VIN 5 SW14 6 L14 7 SW13 8 L13 9 L12 10 SW12 11 L11 12 SW11 13 GND 14 SW10 15 L10 16 SW9 17 L9 18
UHH PACKAGE 56-LEAD (5mm s 9mm) PLASTIC QFN 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 LT3595AEUHH#PBF TAPE AND REEL LT3595AEUHH#TRPBF PART MARKING 3595A PACKAGE DESCRIPTION 56-Lead (5mm × 9mm) Plastic QFN TEMPERATURE RANGE –40°C to 125°C Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
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LT3595A
ELECTRICAL CHARACTERISTICS
PARAMETER VIN Operating Voltage VCC Operating Voltage VCC Input Under Voltage Lockout IVIN Quiescent Current ON, No Switching IVIN Quiescent Current in Shutdown IVCC Quiescent Current ON, No Switching IVCC Quiescent Current in Shutdown IL1-16 Output Current Accuracy IL1-16 Channel-to-Channel Matching Switching Frequency Maximum Duty Cycle Switch Current Limit Switch VCESAT Switch Leakage Current Schottky Forward Drop Schottky Leakage Current SHDN, PWM1-16 Input Low Voltage SHDN, PWM1-16 Input High Voltage SHDN Pin Bias Current PWM1-16 Pin Bias Current OPENLED Pin Voltage O.