AS3644

valid Datasheet AS3644 Ultra Small Low Cost 320mA Inductive White LED Flash Driver 1 General Description The AS3644 is an inductive high efficient DCDC step up converter driving a current source. The DCDC step up converter operates at a fixed frequency of 4MHz and includes soft startup to allow easy integration into noise sensitive RF systems. The current source operates in flash/torch/assist (video/autofocus) mode. The AS3644 includes flash timer, overvoltage, overtemperature, undervoltage and LED short circuit protection functions. The AS3644 is able to detect a broken coil. Together with the LED short and open detection the AS3644 can be used to verify the connection to its external components and allowing in-circuit test. This reduces test time and simplifies production test procedures. The AS3644 is controlled by an I2C interface to allow sophisticated control of all settings like currents and timings. The complete flash driver solution measures only 11mm2 PCB area. The AS3644 is available in a space-saving WL-CSP package measuring only 1.5x1.1x0.6mm and operates over the -30ºC to +85ºC temperature range. Figure 1. Typical Operating Circuit 2 Key Features Total flash driver solution only 11mm2 High efficiency 4MHz fixed frequency DCDC Boost converter with soft start allows small coils LED currents 260mA to 320mA flash current (20mA steps) 51.6mA or 72.3mA Assist light (=torch) current Flash LED(s) cathode connected to ground: Improved thermal performance (gro...