LTC3606B 800mA Synchronous Step-Down DC/DC with Average Input Current Limit FEATURES DESCRIPTION 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% Ef 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 The LTC3606Bs programmable average input current limit Current Mode Operation for Excellent Line and Load is ideal for USB applications and for point-of-load power Transient Response n supplies because the LTC3606Bs limited input current 2% Output Voltage Accuracy n will still allow its output to deliver high peak load cur- Short-Circuit Protected n rents without collapsing the input supply. The operating Shutdown Current 1A n frequency is internally set at 2.25MHz allowing the use of Available in Small Thermally Enhanced 8-Lead small surface mount inductors. Internal soft-start reduces 3mm 3mm DFN Package in-rush current during start-up. The LTC3606B is available in an 8-Lead 3mm 3mm DFN package. APPLICATIONS L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks n High Peak Load Current Applications and Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the n property of their respective owners. Protected by U.S.Patents, including 5481178, 6127815, USB Powered Devices 6304066, 6498466, 6580258, 6611131. n Supercapacitor Charging n Radio Transmitters and Other Handheld Devices TYPICAL APPLICATION Monolithic Buck Regulator with Input Current Limit GSM Pulse Load 1.5H V OUT V 3.4V V IN OUT V SW IN 3.4V AT TO 5.5V 200mV/DIV 800mA LTC3606B 499k C RUN V IN IN 10F + 2.2mF AC-COUPLED PGOOD 2s 1V/DIV 1210k SuperCap V RLIM FB PGOOD I OUT GND 255k 500mA/DIV 116k 1000pF 3606B TA01 I IN 500mA/DIV I = 475mA LIM 3606B TA01b 1ms/DIV V = 5V, 500mA COMPLIANT IN I = 0A to 2.2A LOAD 3606bfb 1LTC3606B ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW Input Supply Voltage (V ) ........................... 0.3V to 6V IN GND 1 8 V FB V ................................................... 0.3V to V + 0.3V FB IN RLIM 2 7 RUN 9 RUN, RLIM ....................................... 0.3V to V + 0.3V IN GND GND PGOOD 3 6 SW ................................................... 0.3V to V + 0.3V IN SW V 4 5 IN PGOOD ............................................. 0.3V to V + 0.3V IN P-Channel SW Source Current (DC) (Note 2) ..............1A DD PACKAGE 8-LEAD (3mm s 3mm) PLASTIC DFN N-Channel SW Source Current (DC) (Note 2) ..............1A T = 125C, = 40C/W JMAX JA Peak SW Source and Sink Current (Note 2) ............. 2.7A EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB Operating Junction Temperature Range (Notes 3, 6, 8) ........................................ 40C to 125C Storage Temperature Range .................. 65C to 125C Re ow Peak Body Temperature ............................260C ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3606BEDD PBF LTC3606BEDD TRPBF LFMB 8-Lead (3mm 3mm) Plastic DFN 40C to 85C LTC3606BIDD PBF LTC3606BIDD TRPBF LFMB 8-Lead (3mm 3mm) Plastic DFN 40C to 125C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: