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Numéro de sérieLT3756
CategoriePower Management => Lighting Controllers
Description100VOUT LED Controller
The LT3756 and LT3756-1 are DC/DC controllers designed to operate as a constant-current source for driving high current LEDs. They drive a low side external N-channel power MOSFET from an internal regulated 7V supply. The fixed frequency, current-mode architecture results in stable operation over a wide range of supply and output voltages. A ground referenced voltage FB pin serves as the input for several LED protection features, and also makes it possible for the converter to operate as a constant-voltage source. A frequency adjust pin allows the user to program the frequency from 100kHz to 1MHz to optimize efficiency, performance or external component size.
SociétéLinear Technology Corporation
DatasheetTélécharger LT3756 datasheet
 
 
  • Description courte

  • DESCRIPTION

    The LT®3756 and LT3756-1 are DC/DC controllers designed to operate as a constant-current source for driving high current LEDs. They drive a low side external N-channel power MOSFET from an internal regulated 7V supply. The fixed frequency, current-mode architecture results in stable operation over a wide range of supply and output voltages. A ground referenced voltage FB pin serves as the input for several LED protection features, and also makes it possible for the converter to operate as a constant-voltage source. A frequency adjust pin allows the user to program the frequency from 1MHz to optimize efficiency, performance or external component size. The LT3756/LT3756-1 sense output current at the high side of the LED string. High side current sensing is the most flexible scheme for driving LEDs, allowing boost, buck mode or buck-boost mode configuration. The PWM input provides LED dimming ratios to 3000:1, and the CTRL input provides additional analog dimming capability. Both parts are available in the 16-lead QFN × 3mm) and MSOP packages.

    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. Protected by U.S. Patents, including 7199560 and 7321203.

    3000:1 True Color PWMTM Dimming Wide Input Voltage Range: to 100V Output Voltage to 100V Constant-Current and Constant-Voltage Regulation 100mV High Side Current Sense Drives LEDs in Boost, Buck Mode, Buck-Boost Mode, SEPIC or Flyback Topology Adjustable Frequency: to 1MHz Open LED Protection Programmable Undervoltage Lockout with Hysteresis Open LED Status Pin (LT3756) Frequency Synchronization (LT3756-1) PWM Disconnect Switch Driver CTRL Pin Provides Analog Dimming Low Shutdown Current: <1A Programmable Soft-Start Thermally Enhanced 16-Lead QFN × 3mm) and MSOP Packages

    APPLICATIONS

    VIN 60V (100V TRANSIENT) 4.7F 1M VREF 332k CTRL INTVCC 100k ISN 40.2k GATE OPENLED PWM SS RT PWMOUT VC GND INTVCC 10k 0.001F

    VIN..........................................................................100V SHDN/UVLO.......................................... 100V, VIN + 0.3V ISP , ISN...................................................................100V INTVCC...................................................... 8V, VIN + 0.3V GATE, PWMOUT........................................INTVCC + 0.3V CTRL, PWM, OPENLED.............................................12V VC, VREF , SS, FB.........................................................3V

    RT............................................................................1.5V SENSE......................................................................0.5V Operating Junction Temperature Range (Note to 125°C Maximum Junction Temperature........................... 125°C Storage Temperature Range................... to 125°C

    TOP VIEW CTRL ISN 17 11 PWMOUT 10 GATE 9 SENSE RT 6 SHDN/UVLO 7 INTVCC 8 VIN ISP VC GATE SENSE VIN INTVCC SHDN /UVLO RT SS SYNC OR OPENLED VREF 1 PWM 2 SYNC OR OPENLED SS 4

    MSE PACKAGE 16-LEAD PLASTIC MSOP TJMAX = 4°C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
    UD PACKAGE s 3mm) PLASTIC QFN TJMAX = 4.2°C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB

    LEAD FREE FINISH LT3756EUD-1#PBF LT3756IUD-1#PBF TAPE AND REEL LT3756EUD-1#TRPBF LT3756IUD-1#TRPBF PART MARKING* LDMQ LDMR PACKAGE DESCRIPTION 16-Lead Plastic MSOP 16-Lead Plastic MSOP 16-Lead Plastic MSOP 16-Lead Plastic MSOP × 3mm) Plastic QFN × 3mm) Plastic QFN × 3mm) Plastic QFN × 3mm) Plastic QFN TEMPERATURE RANGE to 125°C

    Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ This product is only offered in trays. For more information go to: http://www.linear.com/packaging/

    PARAMETER VIN Minimum Operating Voltage VIN Shutdown IQ VIN Operating IQ (Not Switching) VREF Voltage VREF Line Regulation SENSE Current Limit Threshold SENSE Input Bias Current SS Pull-Up Current Error Amplifier LED Current Sense Threshold (VISP ­ VISN) CTRL Threshold Linear Programming Range CTRL Input Bias Current LED Current Sense Amplifier Input Common Mode Range (VISP) ISP/ISN Short-Circuit Threshold (VISP ­ VISN) ISP/ISN Short-Circuit Fault Sensing Common Mode Range (VISN) ISP/ISN Input Bias Current LED Current Sense Amplifier gm VC Output Impedance VC Standby Input Bias Current FB Regulation Voltage (VFB) VISP = VISN FB Amplifier gm FB Pin Input Bias Current FB Open LED Threshold FB Overvoltage Threshold VC Current Mode Gain ­ VVC/VSENSE Oscillator Switching Frequency Minimum Off-Time Linear Regulator INTVCC Regulation Voltage Dropout (VIN ­ INTVCC) INTVCC Undervoltage Lockout INTVCC Current Limit INTVCC Current in Shutdown SHDN/UVLO = 0V, INTVCC = 7V IINTVCC = ­10mA, VIN mA A

    The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are = 25°C. VIN = 24V, SHDN/UVLO = 24V, CTRL = 2V, PWM = 5V, unless otherwise noted.

    CONDITIONS VIN Tied to INTVCC SHDN/UVLO = 0V, PWM = 0V SHDN/UVLO = 1.15V, PWM 100k to GND 100A IVREF 0A 6V VIN 100V 98 Current Out of Pin Current Out of Pin = 0V, VISP = 48V

    LED Current Sense Threshold at CTRL = 0V (VISP ­ VISN) CTRL = 0V, VISP = 48V Current Out of Pin

    2.9 VISN 115 0 PWM = 5V (Active), VISP = 48V PWM = 0V (Standby), VISP = 48V VISP ­ VISN 1V < VVC < 2V PWM = 0V

    FB = VFB, VISP = VISN Current Out of Pin OPENLED Falling (LT3756 Only) PWMOUT Falling