a8435 Allegro MicroSystems, Inc., a8435 Datasheet
a8435
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a8435 Summary of contents
Page 1
... A8435 can output well-matched currents for LEDs, while maintaining the highest efficiency over most of the Li-ion battery lifetime. The A8435 accepts an input range of 2.7 to 5.5 V and delivers for each of the four regulated current sources. The A8435 can deliver a total continuous output current of 120 mA, meeting the requirements of most Li-ion battery-powered white LED backlight applications ...
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... A8435 Selection Guide Part Number A8435EESTR-T 7-in. reel, 1500 pieces/reel *Contact Allegro for additional packing options. VIN CIN 1 µF EN1 EN2 CTRL ISET RSET Ab so lute Max i mum Rat ings Input or Output Voltage VIN, VOUT, C1+, C1–, C2+, and C2– pins ..................... –0 All other pins ..................................................... – ...
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... A8435 Terminal List Table Name Pin Number C1– 13 Negative terminal of capacitor C1. C1+ 16 Positive terminal of capacitor C1. C2– 15 Negative terminal of capacitor C2. C2+ 1 Positive terminal of capacitor C2. Brightness control scheme toggle. For 2-bit parallel or PWM dimming, leave open or tie to VIN CTRL 4 (see table 1). For single-wire serial input dimming, connect to GND (see figure 2). ...
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... A8435 1 ELECTRICAL CHARACTERISTICS 3 μ EN1 EN2 1 2 Characteristics Input Voltage Range Undervoltage Lockout Threshold UVLO Hysteresis Window Quiescent Current Soft-Start Completion Time ISET Bias Voltage ISET Leakage in Shutdown ISET Current Range ISET to LEDx Current Ratio I Accuracy LED ...
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... A8435 Tests performed using application circuit shown in figure 1: dual wire control; and V = 3.6 V, EN1 = EN2 = VIN 120 100 High Efficiency Charge Pump White LED Driver Performance Characteristics = μ OUT SET Efficiency versus Supply Voltage Over Range of Dimming Levels, V ...
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... A8435 Startup Response Symbol Parameter Units/Division BATT OUT t time 500 μs 2-Bit (EN1-EN2) Dimming Response Symbol Parameter Units/Division EN1 OUT t time 5 μs Conditions EN2 = VIN 11-Level Single-Wire Serial Dimming Response Symbol ...
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... High Efficiency Charge Pump White LED Driver Application Information Dimming The A8435 offers serial, 2-bit parallel, and PWM dimming control. When the CTRL pin is pulled LOW, the EN1 pin accepts one-wire serial pulse input both to enable the part, and to select one of the 11 dimming levels, from 100% down to 5% (see can be calculated using table 1) ...
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... A8435 When changing from one specific brightness level to another, the user may not want to keep the existing brightness level stored in memory. A simpler method is to program a shutdown and re-enable, followed by an appropriate number of pulses (from 100%) to reach the target brightness level. The total “LED off” ...
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... A8435 17X 0.08 C +0.05 0.25 –0.07 +0.15 0.40 –0. Copyright ©2005-2008, Allegro MicroSystems, Inc. The products described here are manufactured under one or more U.S. patents or U.S. patents pending. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec tions as may be required to per- mit improvements in the per for mance, reliability, or manufacturability of its products ...