FAN5606

www.fairchildsemi.com FAN5606 Serial LED Driver with Current-Regulated, Step-Up DC/DC Converter Features Drives Up to Six LEDs in Series Pulse Skip PWM Mode of Operation of the Boost Circuit Up to 90% Peak Efficiency No External Schottky Diode Required Up to 25mA Output Built-in DAC for Digital Brightness Control LED’s Current Can be Duty-Cycle-Modulated Digital, Analog, and PWM Brightness Control 2.7V to 5.5V Input Voltage Range 0.5MHz Operating Frequency (8MHz internal clock) Soft Start Low Shutdown Current: ICC < 1µA LED Short Circuit Protection Minimal External Components Needed Available in an 8-lead MLP Package Applications Cell Phones Handheld Computers PDAs, DSCs, MP3 Players Keyboard Backlights LED Display Description The FAN5606 LED driver generates regulated output currents from a battery with input voltage varying between 2.7V to 5V. An internal NMOS switch drives an external inductor, and a Schottky diode delivers the inductor’s stored energy to the load. Soft start circuitry prevents excessive current drawn from the supply during power on. Any number of LEDs can be connected in series as long as the summed forward voltages do not lead to exceeding the specified operating output voltage range. In the FAN5606 device, the internal two-bit D/A converters provide programmability of the output channel current. Analog programming of the output current is also possible in the FAN5606. To do this, ground the “B” pin and connect a r...