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The AL3158 is a low noise, constant frequency charge pumpDC/DC converter that uses a Dual mode load switch (1x), and (2x)conversion for white LED applicaTIons. The AL3158 is capable ofdriving three groups of three LED channels at 20mA from a 2.7V to5.5V input. The current sinks may be operated using three simplePWM dimming inputs individually or in parallel for driving highercurrentLEDs. Low external part counts (one 1μF flying capacitorand two 2.2μF capacitors at VIN and VOUT) make this part ideallysuited for small, battery-powered applicaTIons.AL3158 PWM dimming inputs are used to enable, disable deviceand dimming LED current with a fixed default current setTIngs at20mA or other factory programming opTIons available.Each output of the AL3158 is equipped with built-in protection forVOUT short circuit and auto-disable for LED short conditions. Built-insoft-start circuitry prevents excessive inrush current during start-upand mode switching. A low-current shutdown feature disconnectsthe load from VIN to reduce quiescent current less than 1μA.The AL3158 is available in a lead-free, space-saving, thermallyenhanced 20-pin 3 x 3mm QFN package.
