A8504EECTR-T Allegro Microsystems Inc, A8504EECTR-T Datasheet
A8504EECTR-T
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A8504EECTR-T Summary of contents
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WLED/RGB Backlight Driver for Medium Size LCDs Features and Benefits ▪ Active current sharing among 8 LED strings for ±1.3% typical current matching ▪ ±1.2% typical current accuracy ▪ Drive series × 8 parallel = 88 LEDs ...
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... A8504 WLED/RGB Backlight Driver for Medium Size LCDs Selection Guide Part Number A8504EECTR × QFN/MLP *Contact Allegro for additional packing options Device package is lead (Pb) free, with 100% matte tin leadframe plating. Absolute Maximum Ratings Characteristic SW and OVP Pins LED1 through LED8 Pins ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs ±10 VIN COMP C C Reference and Soft Start SKIP FSET 100 kΩ R FSET AGND GND PWM Generator SEL1 SEL2 SEL3 PWM 100 kΩ ISET ...
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A8504 ELECTRICAL CHARACTERISTICS, valid at T Characteristics Input Voltage Range Undervoltage Lockout Threshold UVLO Hysteresis Window Supply Current Error Amplifier Error Amplifier Open Loop Gain Error Amplifier Unity Gain Bandwidth Error Amplifier Transconductance Error Amplifier Output Sink Current Error Amplifier ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs ELECTRICAL CHARACTERISTICS (continued), valid at T otherwise noted Characteristics LED Current Sinks LEDx Regulation Voltage Current Gain SET LEDx Voltage on ISET Pin I Allowable Current Range SET LEDx ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs V 100 Duty Cycle (%) Duty Cycle (%) ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs 50% Duty Cycle PWM OUT OUT t Symbol Parameter Units/Division C1 V PWM OUT C4 I OUT t time ...
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A8504 The A8504 is a multioutput WLED driver for medium display backlighting. The A8504 works with 4.2 to 5.5 V input supply, and it has an integrated boost converter to boost battery voltage per ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs This current is multiplied internally with a gain of 480, and then mirrored on all enabled LEDx pins. This sets the maximum cur- rent through the LEDs, referred to as “100% current.” ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs The A8504 has protection against open Open LED Protection. LEDs. If any enabled LED string opens, voltage on the corre- sponding LEDx pin goes to zero. The boost loop operates in open ...
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A8504 Design Example This section provides a method for selecting component values when designing an application using the A8504. For the purposes of this example, the following are Assumptions given as the application requirements: • ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs 7. Select output capacitor COUT (connect between the A8504 and the LEDs), given × ∆V C OUT OUT on where I is the total output current, and ∆V ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs Typical Application Circuits A typical application circuit for dimming an LCD monitor back- light with multiple LED strings is shown in figure 1. Figure 8 shows two dimming methods: digital PWM control ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs C C RISET Figure 11. Typical application circuit for PWM dimming, using digital PWM (on the PWM pin). Showing configuration of 16 WLEDs at 160 mA, in two strings of 8 LEDs ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs PCB Layout Guidelines The A8504 evaluation board provides a useful model for design- ing application circuit layouts. The following guidelines should be observed: • Place the supply bypass capacitor, C8, close to ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs Figure 15. A8504 typical PCB layout top signal layer (left) and bottom ground plane layer (right) Recommended Components Table (for application shown in figure 1) Component Capacitor Capacitor Capacitor Diode IC Inductor ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs Terminal List Table Number Name 1 PGND Power ground pin. Reduces boost switching frequency in case of light load to improve frequency. Normally, this pin should be low; when 2 SKIP high, ...
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A8504 WLED/RGB Backlight Driver for Medium Size LCDs Top View D 27X 0.08 C 0.20 0.40 0. Bottom View Copyright ©2007-2009, Allegro MicroSystems, Inc. The products described here are manufactured under one or ...