PIC8518 High Efficiency, Fixed Frequency WLED Driver FEATURES On Board Power MOSFET Drives up to 8 Series White LEDs Up to 87% Efficiency 1.2 MHz Fixed Switching Frequency Open Load Shutdown Low 104mV Feedback Voltage Soft Start/PWM Dimming UVLO, Thermal Shutdown Internal Current Limit Available in 6L-SOT26 APPLICATIONS Cellular and cordless phones Wireless LAN cards Palmtop computers Personal Communication equipment Pen drives Bluetooth devices DESCRIPTION The PIC8518 is a step up converter designed for driving up to 8 series white LEDs from 5V input. The PIC8518 uses current mode, fixed frequency architecture to regulate the LED current, which is measured through an external current sense resistor. Its low 104mV feedback voltage reduces power loss and improves efficiency. The OV pin monitors the output voltage and turns off the converter if an over-voltage condition is present due to an open circuit condition. The PIC8518 includes under-voltage lockout, current limiting and thermal overload protection preventing damage in the event of an output overload. The PIC8518 is available in small 6-pin TSOT26. TYPICAL APPLICATION CIRCUIT www.picsemi.com Road-8, House-2/A, Baridhara Diplomatic Area, Dhaka-1212, Phone: +880-2- 8861966, Fax: +880-2-8835244 1 PIC8518 High Efficiency, Fixed Frequency WLED Driver ELECTRICAL CHARACTERISTICS (All specifications are at TA = +25°C. VIN = 5.0V, unless otherwise specified.) Symbol VIN UVLO Iq ISH FOSC DMAX VFB RDS(ON) ILIM VOV VEN IEN Parameter Operating Input Voltage Under Voltage Lock-out UVLO Hysteresis Supply Current(quiescent) Supply Current(shut-down) Operation Frequency Maximum Duty Cycle Feedback Voltage Feedback Input Bias Current MOSFET ON resistance Current Limit Over Voltage Threshold Enable Threshold Enable Input Bias Current EN Hysteresis Thermal Shut-down Conditions Min 2.5 Typ VIN going Low 2.2 No Switching (VIN=5V,VFB=150mV) VEN = 0 235 VFB=125mV VOV rising VEN Rising VEN Rising, VIN=2.5V VEN = 5V 1.04 85 94 600 1 0.8 0.4 1.2 95 104 1040 0.53 850 30 1.35 Max 5.5 2.4 80 260 Unit V V mV µA 1 1.4 µA MHz % mV nA Ω mA V 114 1.6 6.5 4 165 V µA mV °C www.picsemi.com Road-8, House-2/A, Baridhara Diplomatic Area, Dhaka-1212, Phone: +880-2- 8861966, Fax: +880-2-8835244 2