SC446 High Efficiency Integrated Driver for 3-Strings of 100mA LEDs POWER MANAGEMENT Features Description Wide input voltage range from 4.5V to 27V The SC446 is a high-efficiency multiple string WLED driver with an integrated boost converter. It operates over a 36V maximum output voltage wide input range from 4.5V to 27V with a maximum out- Drives up to 30 WLEDs in 3 strings put voltage of 36V and a 2.5A internal power switch. It Programmable LED current for up to 100mA per can drive up to thirty WLEDs in 3 strings with current up string to 100mA per string. The string-to-string current match- +/- 2% string-to-string current matching ing is 2% typical, 3% maximum. The overall efficiency is Up to 90% efficiency greater than 90% due to the low current sense voltage Wide 0.2% to 100% PWM dimming range and a low-impedance internal power switch. The wide Possible analog dimming PWM dimming range boasts a ratio of 500: 1. Integrated 2.5A power switch 700kHz switching frequency for small size The 700kHz switching frequency enables the user to op- Adjustable OVP for cost-eeff ctive output cap selection timize the external component sizes for efficiency. When Open/short LED protection there are fewer than 10 LEDs in each string, users can ad- Thermal protection with auto-recovery just the output voltage protection yielding an allowable reduction in associated costs, size and voltage ratings of Thermally enhanced TSSOP-16 EDP package the output capacitor. Pb Free, Halogen Free, andWEEE/RoHS Compliant The SC446 also features comprehensive open and short- Applications circuit LED protection functions. It disables the corre- sponding strings with LED open or LED short conditions Medium-sized LCD panel while maintaining normal operation of other, unaffected Notebook Display LED strings. This feature allows LCD panels to remain Automotive Car Navigation Display viewable even under LED failure, wire disconnect, or Sub-Notebook and Tablet Computer Displays short-circuit conditions. The internal thermal shutdown Portable Media Players protects the IC from overheating at abnormal conditions. The SC446 is available in a thermally-enhanced TSSOP-16 EDP package. Typical Application Circuit Vin (4.5V -27V) 1 2 SW VIN VIN VOUT VOUT 3 Strings EN OVOVPPIINN OVPRTN PWM 10 SC446 3 IO1-4 IO1- 3 CCOOMMPP IOSET IOSET AGND AGND SS SS EDP PPGGNNDD www.semtech.com January 28, 2010 1 1SC446 5 4 3 2 1 Pin Configuration Ordering Information Device Package D D (1,2) SC446TETRT TSSOP-16 EDP 1 16 IO2 IO1 SC446EVB Evaluation Board IO3 AGND Notes: PGND SS C C (1) Available in tape and reel only. A reel contains 2,500 devices. (2) Available in lead-free package only. This product is fully WEEE/RoHS COMP SW compliant, Pb free and Halogen free. PGND EN IOSET OVPIN B B OVPRTN PWM VIN VOUT 8 9 A A = 39 C/W JA (TSSOP-16 EDP) 5 4 3 2 1 Marking Information Top Mark Marking for the TSSOP-EP 16 Lead package: nnnnn = Part Number (Example: SC446) yyww = Date (Example: 0952) xxxx = Semtech Lot (Example: E901) 2010 Semtech Corporation www.semtech.com 2