cat4240 Catalyst Semiconductor, cat4240 Datasheet
cat4240
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cat4240 Summary of contents
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... Top View © Catalyst Semiconductor, Inc. Characteristics subject to change without notice DESCRIPTION The CAT4240 is a DC/DC step-up converter that delivers an accurate constant current ideal for driving LEDs. Operation at a fixed switching frequency of 1MHz allows the device to be used with small value external ceramic capacitors and inductor ...
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... CAT4240 ABSOLUTE MAXIMUM RATINGS Parameters voltage IN ¯¯¯¯¯ voltage SHDN SW voltage Storage Temperature Range Junction Temperature Range Lead Temperature RECOMMENDED OPERATING CONDITIONS Typical application circuit with external components are shown on page 1. Parameters pin voltage (1) Ambient Temperature Range ...
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... Catalyst Semiconductor, Inc. Characteristics subject to change without notice Quiescent Current vs. VIN (Switching) 2.0 1.5 1.0 0.5 0.0 3.0 5.0 5.5 FB Pin Voltage vs. Output Current 310 305 300 295 290 100 150 Switch ON Resistance vs. Input Voltage 2.0 1.5 1.0 0.5 0.0 5.0 5.5 3 CAT4240 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE [V] 4 LEDs 0 50 100 150 200 OUTPUT CURRENT [mA] 3.0 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE [V] Doc. No. MD-5026 Rev. C ...
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... CAT4240 TYPICAL CHARACTERISTICS VIN = 5V 13V 25ºC, typical application circuit unless otherwise specified. L AMB LED Current vs. Input Voltage 350 RSET = 1Ω VOUT = 19.5V 300 250 200 RSET = 2Ω VOUT = 18.8V 150 100 INDUCTOR VOLTAGE [V] Efficiency vs. Load Current (6 LEDs) ...
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... INDUCTOR VOLTAGE [V] Switch Current Limit 1200 1100 1000 900 800 VOUT = 20V 700 2.5 3.0 3.5 4.0 4.5 INPUT VOLTAGE [V] © Catalyst Semiconductor, Inc. Characteristics subject to change without notice VOUT = 30V 5.0 5.5 5 CAT4240 Shutdown Voltage 1.0 -40°C -25°C 0.8 0.6 125°C 0.4 85°C 0.2 3.0 3.5 4.0 4.5 INPUT VOLTAGE [V] Doc. No. MD-5026 Rev. C 5.0 ...
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... CAT4240 PIN DESCRIPTION VIN is the supply input for the internal logic. The device is compatible with supply voltages down to 2.8V and up to 5.5V recommended that a small bypass ceramic capacitor (4.7μF) be placed between the VIN and GND pins near the device. If the supply voltage drops below 1.9V, the device stops switching. ...
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... Catalyst Semiconductor, Inc. Characteristics subject to change without notice When the inductor is connected supply or higher, the CAT4240 can drive 6 LEDs in series at 300mA delivering a total power of 6 Watts into the load. A separate 5V supply voltage is connected to the VIN pin. In the event of an “Open LED” fault condition, where the feedback control loop becomes open, the output voltage will continue to increase ...
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... X5R and X7R capacitor types are ideal due to their stability across temperature range. Inductor A 47µH inductor is recommended for most of the CAT4240 applications. In cases where the efficiency is critical, inductances with lower series resistance are preferred. Inductors with current rating of 800mA or higher are recommended for most applications. ...
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... OPEN LED PROTECTION In the event of an “Open LED” fault condition, the CAT4240 will continue to boost the output voltage with maximum power until the output voltage reaches approximately 40V. Once the output exceeds this level, the internal circuitry immediately places the device into a very low power mode where the total input power is limited to about 6mW (about 1 ...
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... Filtered PWM Signal A filtered PWM signal used as a variable DC voltage can control the LED current. Figure 2 shows the PWM control circuitry connected to the CAT4240 FB pin. The PWM signal has a voltage swing 2.5V. The LED current can be dimmed within a range from 0mA to 20mA. The PWM signal frequency can vary from very low frequency up to 100kHz. ¯ ...
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... VIN pin and GND. The capacitor C2 has to be connected separately to the top LED anode. A ground plane under the CAT4240 allows for direct connection of the capacitors to ground. The resistor R1 must be connected directly to the GND pin of the CAT4240 and not shared with the switching current loops and any other components. D ...
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... CAT4240 PACKAGE OUTLINE DRAWING (1)(2) TSOT-23 5-Lead (TD TOP VIEW b SIDE VIEW For current Tape and Reel information, download the PDF file from: http://www.catsemi.com/documents/tapeandreel.pdf. Notes: (1) All dimensions are in millimeters, angles in degrees. (2) Complies with JEDEC standard MO-193. Doc. No. MD-5026 Rev. C SYMBOL MIN ...
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... All packages are RoHS-compliant (Lead-free, Halogen-free). (2) The standard lead finish is NiPdAu. (3) The device used in the above example is a CAT4240–GT3 (TSOT-23, NiPdAu, Tape & Reel). (4) For additional package and temperature options, please contact your nearest Catalyst Semiconductor Sales office. -free, Halogen-free). ...
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... Catalyst Semiconductor products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Catalyst Semiconductor product could create a situation where personal injury or death may occur ...