LTC3606B 800mA Synchronous Step-Down DC/DC with Average Input Current Limit FEATURESDESCRIPTION n Programmable Average Input Current Limit: The LTC®3606B is an 800mA monolithic synchronous ±5% Accuracy buck regulator using a constant frequency current mode n Step-Down Output: Up to 96% Effi ciency architecture. n Low Noise Pulse-Skipping Operation at Light Loads The input supply voltage range is 2.5V to 5.5V, making it n Input Voltage Range: 2.5V to 5.5V ideal for Li-Ion and USB powered applications. 100% duty n Output Voltage Range: 0.6V to 5V cycle capability provides low dropout operation, extending n 2.25MHz Constant-Frequency Operation the run time in battery-operated systems. Low output n Power Good Output Voltage Monitor voltages are supported with the 0.6V feedback reference n Low Dropout Operation: 100% Duty Cycle voltage. The LTC3606B can supply 800mA output current. n Internal Soft-Start n Current Mode Operation for Excellent Line and Load The LTC3606B’s programmable average input current limit Transient Response is ideal for USB applications and for point-of-load power n ±2% Output Voltage Accuracy supplies because the LTC3606B’s limited input current n Short-Circuit Protected will still allow its output to deliver high peak load cur- n Shutdown Current ≤ 1μA rents without collapsing the input supply. The operating n Available in Small Thermally Enhanced 8-Lead frequency is internally set at 2.25MHz allowing the use of 3mm × 3mm DFN Package small surface mount inductors. Internal soft-start reduces in-rush current during start-up. The LTC3606B is available APPLICATIONS in an 8-Lead 3mm × 3mm DFN package. n High Peak Load Current Applications L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks and Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the n USB Powered Devices property of their respective owners. Protected by U.S.Patents, including 5481178, 6127815, n 6304066, 6498466, 6580258, 6611131. Supercapacitor Charging n Radio Transmitters and Other Handheld Devices TYPICAL APPLICATIONMonolithic Buck Regulator with Input Current LimitGSM Pulse Load 1.5μH V VOUT IN 3.4V V V SW OUT TO 5.5V IN 3.4V AT 200mV/DIV LTC3606B 800mA 499k CIN RUN VIN 10μF + 2.2mF AC-COUPLED PGOOD s2 1210k 1V/DIV V SuperCap RLIM FB PGOOD I GND OUT 255k 500mA/DIV 116k 1000pF 3606B TA01 IIN 500mA/DIV ILIM = 475mA 1ms/DIV 3606B TA01b VIN = 5V, 500mA COMPLIANT ILOAD = 0A to 2.2A 3606bfb 1