a8434 Allegro MicroSystems, Inc., a8434 Datasheet
a8434
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a8434 Summary of contents
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... Figure 1.6 × WLED display 8434-DS, Rev. 2 Description The A8434 high efficiency charge pump ICs offer a simple, low-cost WLED (white LED) driver solution for driving up to six WLEDs in various application configurations, either all six backlighting a single display, or for multiple displays, such as ...
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... A Junction Temperature, T .............................................................. 150°C J(max) Storage Temperature, T ................................................... –55°C to 150°C S Use the following complete part number when ordering: Part Number A8434EESTR-T *Contact Allegro for additional packing options. 6-Channel High Efficiency Charge Pump Functional Block Diagram C1 1 μF C1 − C1+ C2+ Fractional Charge Pump (1× ...
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... A8434 Terminal List Table Name Number C1– 13 Negative terminal of capacitor C1. Connect capacitor C1 between C1+ and C1–. C1+ 16 Positive terminal of capacitor C1. C2– 15 Negative terminal of capacitor C2 C2+ 1 Positive terminal of capacitor C2. Connect capacitor C2 between C2+ and C2–. ENS 4 Enable and dimming control input for sub display WLED group. ...
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... A8434 a ELECTRICAL CHARACTERISTICS T = –40°C to +85°C; typical values are 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 for LED1 through LED6 ...
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... A8434 Efficiency versus Supply Voltage V falling 3 100.0 95.0 Sub 90.0 85.0 Main 80.0 75.0 70.0 Main + Sub 65.0 60.0 55.0 2.7 3.1 3.5 3.9 V (V) IN Logic Level 1.2 1 1.0 0.9 0.8 0.7 0.6 0.5 2.7 3.1 3.5 3 (V) 6-Channel High Efficiency Charge Pump Performance Characteristics Tests performed using application circuit shown in figure 25° 3.6 V (unless otherwise noted 100.0 95 ...
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... A8434 6-Channel High Efficiency Charge Pump Performance Characteristics Tests performed using application circuit shown in figure 25° 3.6 V (unless otherwise noted Turn ON LED1 through LED6 to 1X Mode 120 mA OUT t Symbol Parameter Units/Division C2 V and V ENM ...
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... A8434 C3 C4 LED1 through LED6 ON, 1.5X Mode 120 mA OUT Symbol Parameter C3 V OUT(RIPPLE IN(RIPPLE) t time 6-Channel High Efficiency Charge Pump Performance Characteristics Tests performed using application circuit shown in figure 25° 3.6 V (unless otherwise noted LED1 through LED6 ON, 2X Mode ...
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... IN the 150 mV threshold. When V falls below 150 mV, the IC LEDx enters 1.5× mode. When the A8434 switches from 1× to 2× mode, it first switches to 1.5× mode for a typical duration before entering 2× mode. When operating in 1.5× mode OUT switches back to 1× mode every 130 ms, and then reenters 1.5× ...
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... When the ENM or ENS pin is pulled low for 0 longer, the corresponding display channels are shut off and dimming is reset to 100% upon the next ENM or ENS going high edge. When both ENM and ENS are pulled low for 0 longer, the A8434 enters the shutdown mode. Short Circuit Protection The A8434 is protected against short circuits on the output ...
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... Normal operation will be resumed when the fault is removed. LED Disconnection Every LEDx pin has a disable subcircuit, as shown in figure 7. The A8434 compares the voltage on each LED pin, and if the voltage on the pin is greater than either V V – 0.4 V, then the corresponding LED pin is disabled. ...
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... A8434 17X 0.08 C +0.05 0.25 –0.07 +0.15 0.40 –0. Copyright ©2006-2008, 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 ...