LT3503 1A, 2.2MHz Step-Down Switching Regulator in 2mm × 3mm DFN UFEATURESDESCRIPTIO ■ Wide Input Range: 3.6V to 20V The LT®3503 is a current mode PWM step-down DC/DC ■ 5V at 1.2A from 11V to 18V Input converter with an internal 1.45A power switch. The wide ■ 5V at 1A from 7.2V to 18V Input operating input range of 3.6V to 20V makes the LT3503 ■ 3.3V at 1.2A from 8.5V to 12V Input ideal for regulating power from a wide variety of sources. ■ 3.3V at 1A from 5.5V to 12V Input Its high operating frequency allows the use of tiny, low ■ Fixed Frequency Operation: 2.2MHz cost inductors and ceramic capacitors, resulting in low, ■ Output Adjustable Down to 780mV predictable output ripple. ■ Short-Circuit Robust Cycle-by-cycle current limit provides protection against ■ Uses Tiny Capacitors and Inductors shorted outputs and soft-start eliminates input current ■ Soft-Start surge during start-up. The low current (<2µA) shutdown ■ Internally Compensated mode provides output disconnect, enabling easy power ■ Low Shutdown Current: <2µA management in battery-powered systems. ■ Low VCESAT Switch: 400mV at 1A ■ Thermally Enhanced, 2mm × 3mm 6-Pin DFN , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Low Profile Package UAPPLICATIO S ■ Automotive Battery Regulation ■ Industrial Control Supplies ■ Wall Transformer Regulation ■ Distributed Supply Regulation ■ Battery-Powered Equipment UTYPICAL APPLICATIO3.3V Step-Down ConverterEfficiency 85 V V IN = 12V V OUT IN 3.3V 80 4.5V TO 12V VIN BOOST 1A, V 20V MAX IN > 5.5V LT3503 0.1µF 2.5µH 1.2A, VIN > 8.5V 75 ON OFF SHDN SW 37.4k 120pF 70 GND FB 10µF 65 1µF 11.5k EFFICIENCY (%) 60 3503 TA01a 55 50 0 0.2 0.4 0.6 0.8 1.0 1.2 LOAD CURRENT (A) 3503 TA01b 3503f 1