a8481 Allegro MicroSystems, Inc., a8481 Datasheet
a8481
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a8481 Summary of contents
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... IC ideally suited for battery operated, dual display portable applications. The IC disconnects input from the output path during shutdown, allowing shutdown currents less than 1 μA. The A8481 is available in a 10-pin 3 mm × MLP package that has a nominal height of only 0.75 mm. Applications include: ▪ ...
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... J Storage Temperature, T .............................................. –55°C to 150°C S Ordering Information Use the following complete part numbers when ordering: Part Number A8481EEJTR-T b 7-in. reel, 1500 pieces/reel a Contact Allegro for additional packing options. b Lead (Pb) free, with leadframe plating 100% matte tin. Functional Block Diagram ...
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... A8481 Dual Output Boost Regulator Using Single Inductor Number Name 1 GND Power ground and signal ground reference; connect directly to the ground plane. This is the feedback pin for controlling voltage on the OUT1 pin. The nominal reference 2 FB1 voltage on this pin is 600 mV. In order to minimize noise, connect the feedback resistor network close to this pin ...
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... A8481 Dual Output Boost Regulator Using Single Inductor ELECTRICAL CHARACTERISTICS at T Characteristics Input Voltage Range Undervoltage Lockout Threshold Feedback Reference Voltage Feedback Voltage Line Regulation Feedback Input Current Switch Current Limit Switch Frequency Switch Maximum Duty Cycle * Switch S1 On Resistance Switch Leakage Current ...
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... A8481 Dual Output Boost Regulator Using Single Inductor Tests performed using application circuit shown in figure 1( 4.7 μH, C Over range of dimming levels, LED voltage drop 16.3 V Over range of dimming levels, LED voltage drop Performance Characteristics = μ 25° (unless otherwise noted) ...
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... A8481 Dual Output Boost Regulator Using Single Inductor Tests performed using application circuit shown in figure 1( 4.7 μH, C OLED Line Regulation OUT1 16.25 16.20 16. 16. 16. 16. 15.95 15.90 15. (V) IN WLED Startup, 5 LEDs Symbol Parameter Units/Division C1 V ON2 C2 I LED ...
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... A8481 Dual Output Boost Regulator Using Single Inductor Tests performed using application circuit shown in figure 1( 4.7 μH, C Symbol Parameter Units/Division OUT1 CAP OUT2 C4 I 200 time ON2 C1 I OUT2 C2 t Symbol Parameter Units/Division ...
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... WLED Dimming Control In the A8481, WLED brightness can be controlled by the foll- wing variety of methods: • External resistance on the ISET pin Dimming level can be set by controlling the resistance between the ISET pin and ground. The resistance between the ISET pin ...
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... A8481 Dual Output Boost Regulator Using Single Inductor Dimming with serial programming is disabled during startup, for the initialization period When ON2 is pulled low for time HII longer than t , the counter resets. SHDN When changing from one specific dimming level to another, the user may not want to have to store the latest dimming level. ...
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... A8481 Dual Output Boost Regulator Using Single Inductor Component Selection The component values shown in the application circuits (figures 1 and 4) will be sufficient for most applications. To reduce the output ripple, the output inductor may be increased in value, but in most cases this will result in excessive board area and cost. ...
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... Backlight D3 COUT D4 V SUPPLY D5 D6 Flash D7 RSET R2 Figure 4e. WLED Main and WLED sub driver GND SW CIN 2 9 FB1 CAP A8481 3 8 VIN OUT1 4 7 OUT2 ISET 5 6 ON2 ON1 RSET Efficiency versus Input Voltage ...
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... A8481 Dual Output Boost Regulator Using Single Inductor 11X 0.08 C 0.25 0. 0.40 10 Copyright ©2006, 2007, 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 ...