ltc3490 Linear Technology Corporation, ltc3490 Datasheet
ltc3490
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ltc3490 Summary of contents
Page 1
... It contains a 100mΩ NFET switch and a 130mΩ PFET synchronous rectifier. The fixed switching frequency is internally set to 1.3MHz. The LTC3490 limits the output voltage to 4.7V if the output load is disconnected. It also features an analog dimming capability that reduces the drive current proportional to the CTRL/SHDN pin voltage ...
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... Operating Temperature Range (Note 2) .. – 40°C to 85°C Storage Temperature Range ................. – 65°C to 125°C Lead Temperature (Soldering, 10 sec, S8) .......... 300° CTRL/SHDN LOBAT CAP LED ORDER PART NUMBER LTC3490ES8 LBRQ The ● denotes specifications which apply over the full operating = 25° 2.5V unless otherwise specified CONDITIONS ...
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... Specifications over the –40°C to 85°C range are assured by design, characterization and correlation with statistical process controls. Note 3: The LTC3490 input voltage may drop below the minimum start-up voltage once the LED voltage has risen above 2.3V. W ...
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... LTC3490 W U TYPICAL PERFOR A CE CHARACTERISTICS LED LED 360 V = 2.4V IN 358 356 354 352 350 348 346 344 342 340 2.8 3 3.2 3.4 V (V) LED CTIO S CELLS (Pin 1): A logic input to set the low-battery and undervoltage shutdown thresholds. A logic low (tied to GND) will set the thresholds for 1 cell ...
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... CTRL/ SHDN + 8 CELLS – P BODY CONTROL + GATE CONTROL AND DRIVERS SENSE AMP LIMIT PWM OVERVOLTAGE LOGIC DETECT OSCILLATOR DIMMING AMP I REF BATTERY MONITOR GND 4 LTC3490 CAP 6 19.2Ω 0.1Ω + – LED 5 250k – 40k + V /2 REF LOBAT 7 SHUTDOWN 3490 FD 3490fa 5 ...
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... LEDs. These high intensity LEDs require a fixed current of 350mA with a voltage compliance of 2.8V to 4V. The LTC3490 operates with NiMH or alkaline cells. It functions as a boost converter with a current sense re- sistor providing the control feedback. If the battery voltage is greater than the required LED compliance, it will cycle off periodically to maintain the correct average current ...
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... Optional components include an input capacitor and dimming resistors. COMPONENT SELECTION Inductor Selection The high frequency operation of the LTC3490 allows the use of small surface mount inductors. The minimum inductance value is proportional to the operating fre- quency and is limited by the following constraints: 3 ≥ ...
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... LTC3490 U U APPLICATIO S I FOR ATIO The output ripple voltage has two primary components. The first is due to the value of the capacitor and is given by: I • V LPK CAP C V • • f OUT The second is due to the capacitor ESR • R ESR ...
Page 9
... The red, red-orange and amber Luxeon LEDs have a lower forward voltage than the white, blue and green LEDs. Since the LTC3490 internal circuitry is powered from the output, it requires a minimum LED voltage of 2.5V for reliable operation. The minimum forward voltage on the red LEDs ...
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... Luxeon Red LED Driver Without Dimming 3.3µH ON/OFF CAP LTC3490 + CTRL/SHDN LED CELLS LOBAT 1M GND Luxeon Red LED Driver with Dimming 3.3µH ON/OFF CAP LTC3490 + CTRL/SHDN LED 1M CELLS LOBAT GND Efficiency vs V with Red LED IN 90 RESISTOR 80 SCHOTTKY ...
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... TYP .016 – .050 .014 – .019 (0.406 – 1.270) (0.355 – 0.483) TYP INCHES (MILLIMETERS) LTC3490 R = 0.115 TYP 5 3.00 ±0.10 1.65 ± 0.10 (4 SIDES) (2 SIDES) 4 0.25 ± 0.05 0.75 ±0.05 2.38 ±0.10 (2 SIDES) 0.00 – ...
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... Inrush Current Protection ThinSOT is a trademark of Linear Technology Corporation. Linear Technology Corporation 12 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● 3.3µH ON/OFF CAP LTC3490 1M 350mA/70mA CTRL/SHDN LED CELLS LOBAT 1M 432k GND COMMENTS V : 1.6V to 18V Packages ...