LTC3619B 400mA/800mA Synchronous Step-Down DC/DC with Average Input Current Limit Fea T Descrip T n Programmable Average Input Current Limit: The LTC 3619B is a dual monolithic synchronous buck 5% Accuracy regulator using a constant frequency current mode ar- n Dual Step-Down Outputs: Up to 96% Efficiency chitecture. 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, extend- n 2.25MHz Constant-Frequency Operation ing the run time in battery-operated systems. Low output n Power Good Output Voltage Monitor for Each Channel voltages are supported with the 0.6V feedback reference n Low Dropout Operation: 100% Duty Cycle voltage. Channel 1 and channel 2 can supply 400mA and n Independent Internal Soft-Start for Each Channel 800mA output current, respectively. n Current Mode Operation for Excellent Line and Load The LTC3619Bs programmable average input current limit Transient Response n is ideal for USB applications and for point-of-load power 2% Output Voltage Accuracy n supplies because the LTC3619Bs limited input current Short-Circuit Protected n will still allow its output to deliver high peak load currents Shutdown Current 1A n without collapsing the input supply. When the sum of Available in Small Thermally Enhanced 10-Lead MS both channels currents exceeds the input current limit, and 3mm 3mm DFN Packages channel 2 is current limited while channel 1 remains regu- lated. The operating frequency is internally set at 2.25MHz a T allowing the use of small surface mount inductors. Internal n High Peak Load Current Applications soft-start reduces in-rush current during start-up. The n USB Powered Devices LTC3619B is available in small MSOP and 3mm 3mm n Supercapacitor Charging DFN packages. The LTC3619B is also available in a low n Radio Transmitters and Other Handheld Devices quiescent current, high efficiency Burst Mode version, 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 LTC3619. property of their respective owners. Protected by U.S. Patents, including 5481178, 6127815, 6304066, 6498466, 6580258, 6611131. Typical a T Dual Monolithic Buck Regulator in 10-Lead 3mm 3mm DFN GSM Pulse Load V IN 3.4V TO 5.5V V OUT 10F 200mV/DIV RUN2 V RUN1 IN PGOOD2 PGOOD1 V IN AC-COUPLED LTC3619B 1.5H 3.3H V V 1V/DIV OUT2 OUT1 1.8V AT 3.4V AT SW2 SW1 400mA 800mA 22pF I OUT 500mA/DIV 1190k V V FB2 FB1 + I IN 2.2mF 511k 255k RLIM GND 10F 255k 500mA/DIV 2 3619B TA01b 1ms/DIV SuperCap 3619B TA01 V = 5V, 500mA COMPLIANT IN I = 0A to 2.2A, CHANNEL 1 UNLOADED 1000pF 116k LOAD I = 475mA LIM 3619bfb 1 ion pplica ions pplica ion uresLTC3619B a T e Maxi Mu M r a T (Note 1) Input Supply Voltage (V ) ............................. 0.3 to 6V Peak SW Source and Sink Current (Note 2) IN V , V ........................................ 0.3V to V + 0.3V Channel 1 ........................................................ 900mA FB1 FB2 IN RUN1, RUN2, RLIM .......................... 0.3V to V + 0.3V Channel 2 ............................................................. 2.7A IN SW1, SW2 ........................................ 0.3V to V + 0.3V Operating Junction Temperature Range IN PGOOD1, PGOOD2 ........................... 0.3V to V + 0.3V (Notes 3, 6, 8) ........................................40 to 125C IN P-channel SW Source Current (DC) (Note 2) Storage Temperature Range .................. 65C to 125C Channel 1 ........................................................ 600mA Lead Temperature (Soldering, 10 sec) Channel 2 ................................................................1A MSOP Package .................................................300C N-channel SW Source Current (DC) (Note 2) Reflow Peak Body Temperature ............................260C Channel 1 ........................................................ 600mA Channel 2 ................................................................1A p c F T TOP VIEW TOP VIEW V 10 V 1 FB1 FB2 10 V V 1 FB1 FB2 RUN1 9 RUN2 2 9 RUN2 RUN1 2 11 11 8 PGOOD2 RLIM 3 RLIM 3 8 PGOOD2 GND GND 7 SW2 PGOOD1 4 PGOOD1 4 7 SW2 6 V SW1 5 IN SW1 5 6 V IN MSE PACKAGE 10-LEAD PLASTIC MSOP DD PACKAGE T = 125C, = 45C/W JMAX JA 10-LEAD (3mm 3mm) PLASTIC DFN EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB T = 125C, = 40C/W JMAX JA EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB o r D i n F Ma T LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3619BEDD PBF LTC3619BEDD TRPBF LFFH 10-Lead (3mm 3mm) Plastic DFN 40C to 125C LTC3619BIDD PBF LTC3619BIDD TRPBF LFFH 10-Lead (3mm 3mm) Plastic DFN 40C to 125C LTC3619BEMSE PBF LTC3619BEMSE TRPBF LTFFJ 10-Lead Plastic MSOP 40C to 125C LTC3619BIMSE PBF LTC3619BIMSE TRPBF LTFFJ 10-Lead Plastic MSOP 40C to 125C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: