LT3756 LINER [Linear Technology], LT3756 Datasheet
LT3756
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LT3756 Summary of contents
Page 1
... A frequency adjust pin allows the user to program the frequency from 100kHz to 1MHz to optimize effi ciency, 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 fl exible scheme for driving LEDs, allowing boost, buck mode or buck-boost mode confi ...
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... LT3756EMSE-1#TRPBF LT3756IMSE-1#PBF LT3756IMSE-1#TRPBF LT3756EUD#PBF LT3756EUD#TRPBF LT3756IUD#PBF LT3756IUD#TRPBF LT3756EUD-1#PBF LT3756EUD-1#TRPBF LT3756IUD-1#PBF LT3756IUD-1#TRPBF Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi label on the shipping container. For more information on lead free part marking, go to: This product is only offered in trays ...
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... ISP V – 100mV ISP ISN 1V < V < PWM = ISP ISN ISP ISN Current Out of Pin OPENLED Falling (LT3756 Only) PWMOUT Falling R = 100k 10k –10mA INTVCC IN SHDN/UVLO = 0V, INTV = 7V CC LT3756/LT3756-1 MIN TYP MAX UNITS ...
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... C = 3300pF L Note 2: The LT3756E and LT3756E-1 are 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 LT3756I and LT3756I-1 are guaranteed to meet performance specifi ...
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... Switching Frequency vs Temperature 1400 R = 10k T 1300 1200 1100 1000 900 800 700 600 100 –50 – TEMPERATURE (°C) LT3756/LT3756 25°C, unless otherwise noted – V Threshold ISP ISN vs Temperature 103 CTRL 102 101 100 – ...
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... LT3756/LT3756-1 TYPICAL PERFORMANCE CHARACTERISTICS Quiescent Current 2.0 1.5 1.0 0 (V) IN 37561 G10 INTV Voltage (V) IN 37561 G13 SENSE Current Limit Threshold vs Duty Cycle 110 105 100 DUTY CYCLE (%) ...
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... PWM input was high. When PWM input goes high again, the OPENLED pin will be updated. This pin may be used to report an open LED fault. SYNC (Pin 9/Pin 3, LT3756-1 Only): The SYNC pin is used to synchronize the internal oscillator to an external logic level signal. The R an internal switching frequency 20% slower than the SYNC pulse frequency. Gate turn-on occurs a fi ...
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... TO 1MHz OSCILLATOR FAULT 10μA LOGIC + 1.25V + – FREQ TSD PROG SS SENSE and GND. Driven to GND during CC PWM V IN LDO – 1.25V A8 + INTV 7V CC GATE R Q DRIVER S I SENSE SENSE + A4 – GND OPENLED – 1.2V (LT3756 ONLY SYNC (LT3756-1 ONLY the 37561f ...
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... LED current loop entirely, the ISP and ISN should be tied together and the CTRL input tied to V Two LED specifi c functions featured on the LT3756 are controlled by the voltage feedback pin. First, when the FB pin exceeds a voltage 50mV lower (–4%) than the FB regulation voltage, the pull-down driver on the OPENLED pin is activated ...
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... Place the capacitor close to the IC to minimize the trace length to the INTV pin and also to the IC ground internal current limit on the INTV the LT3756 from excessive on-chip power dissipation. The minimum value of this current should be considered when choosing the switching NMOS and the operating frequency. I ...
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... Dimming Control There are two methods to control the current source for dimming using the LT3756. One method uses the CTRL pin to adjust the current regulated in the LEDs. A second method uses the PWM pin to modulate the current source between zero and full current to achieve a precisely pro- grammed average current ...
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... LT3756/LT3756-1 APPLICATIONS INFORMATION signal goes high. To further improve the recovery time, a disconnect switch may be used in the LED current path to prevent the ISP node from discharging during the PWM signal low phase. The minimum PWM on or off time will depend on the choice of operating frequency through the RT input ...
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... APPLICATIONS INFORMATION Thermal Considerations The LT3756 and LT3756-1 are rated to a maximum input voltage of 100V. Careful attention must be paid to the internal power dissipation of the IC at higher input volt- ages to ensure that a junction temperature of 125°C is not exceeded. This junction limit is especially important when operating at high ambient temperatures ...
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... WEB of switch on-resistance, R www.tdk.com cause switching losses dominate power loss. The INTV www.kemet.com regulator on the LT3756 has a fi xed current limit to protect www.murata.com the IC from excessive power dissipation at high V www.t-yuden.com FET should be chosen so that the product of Q switching frequency does not exceed the INTV limit ...
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... I LED LED The placement of R should be close to the source of SENSE the NMOS FET and GND of the LT3756. The SENSE input to LT3756 should be a Kelvin connection to the positive terminal SENSE Inductor Selection The inductor used with the LT3756 should have a saturation ...
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... L1: COILTRONICS DR127-220 RT1: MURATA NCP18WM104J M2: VISHAY SILICONIX Si2328DS D2: IN4448HWT 16 the LT3756. Likewise, the ground terminal of the bypass capacitor for the INTV the GND of the switching path. Typically, this requirement will result in the external switch being closest to the IC, along with the INTV the compensation network and other DC control signals should be star connected to the underside of the IC ...
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... L1A 1μF 33μH D1 1:1 511k FB L1B 25k ISP 0.1Ω 1A ISN M1 GATE 20W LED 0.033Ω STRING CC C2 4.7μF 10V M2 3756 TA04a LT3756/LT3756-1 Effi ciency 100 OUT C3 4.7μ (V) IN Effi ciency vs V 100 C3 10μ 35V ...
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... LT3756/LT3756-1 PACKAGE DESCRIPTION 3.835 0.102 (.151 .004) 5.23 (.206) MIN 0.305 0.038 (.0120 .0015) TYP RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) GAUGE PLANE 0.18 (.007) 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" ...
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... Plastic QFN (3mm × 3mm) (Reference LTC DWG # 05-08-1691) 0.70 ±0.05 PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC 0.75 ± 0.05 3.00 ± 0.10 (4 SIDES) 1.45 ± 0.10 (4-SIDES) 0.200 REF 0.00 – 0.05 LT3756/LT3756-1 BOTTOM VIEW—EXPOSED PAD PIN 1 NOTCH R = 0.20 TYP R = 0.115 OR 0.25 × 45° CHAMFER TYP 15 16 0.40 ± 0. (UD16) QFN 0904 0.25 ± 0.05 0.50 BSC ...
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... Buck Mode 1A LED Driver with High Dimming Ratio and Open LED Reporting V IN 24V TO C1 80V 1M V ISP IN 1μF SHDN/UVLO 61.9k V ISN REF FB CTRL PWM PWMOUT LT3756 INTV CC 100k OPENLED SS GATE RT SENSE 0.1μF VC GND INTV CC 28.7k 10k 47k 400kHz 0.001μF 3756 TA05a ...