LTC3619 400mA/800mA Synchronous Step-Down DC/DC with Average Input Current Limit Fea T Descrip T n Programmable Average Input Current Limit: The LTC 3619 is a dual monolithic synchronous buck 5% Accuracy regulator using a constant frequency, current mode n architecture. Dual Step-Down Outputs: Up to 96% Efficiency n Low Ripple (<25mV ) Burst Mode Operation: P-P The input supply voltage range is 2.5V to 5.5V, making it I = 50A Q ideal for Li-Ion and USB powered applications. 100% duty n Input Voltage Range: 2.5V to 5.5V cycle capability provides low dropout operation, extend- n Output Voltage Range: 0.6V to 5V ing the run time in battery-operated systems. Low output n 2.25MHz Constant-Frequency Operation voltages are supported with the 0.6V feedback reference n Power Good Output Voltage Monitor for Each Channel voltage. Channel 1 and channel 2 can supply 400mA and n Low Dropout Operation: 100% Duty Cycle 800mA output current, respectively. n Independent Internal Soft-Start for Each Channel The LTC3619s programmable average input current limit n Current Mode Operation for Excellent Line and Load is ideal for USB applications and for point-of-load power Transient Response supplies because the LTC3619s limited input current will n 2% Output Voltage Accuracy still allow its output to deliver high peak load currents n Short-Circuit Protected without collapsing the input supply. When the sum of both n Shutdown Current 1A channels currents exceeds the input current limit, channel 2 n Available in Small Thermally Enhanced 10-Lead MSE is current limited while channel 1 remains regulated. The and 3mm 3mm DFN Packages operating frequency is internally set at 2.25MHz allowing the use of small surface mount inductors. Internal soft-start a T reduces in-rush current during start-up. The LTC3619 is available in small MSOP and 3mm 3mm DFN packages n High Peak Load Current Applications and is also available in a low noise, high efficiency pulse- n USB Powered Devices skipping version, LTC3619B. n Supercapacitor Charging n L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks Radio Transmitters and Other Handheld Devices and Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the 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 V 3.4V TO 5.5V OUT2 200mV/DIV 10F RUN2 V RUN1 IN V IN PGOOD2 PGOOD1 1V/DIV AC-COUPLED LTC3619 1.5H 3.3H V V OUT2 OUT1 1.8V AT 3.4V AT SW2 SW1 22pF 400mA 800mA I OUT 500mA/DIV 1190k V V FB2 FB1 + I IN 2.2mF 511k 255k RLIM GND 10F 255k 500mA/DIV 2 3619 TA01b SuperCap 3619 TA01a 1ms/DIV 1000pF 116k V = 5V, 500mA COMPLIANT, IN I = 0A TO 2.2A, CHANNEL 1 UNLOADED LOAD I = 475mA LIM 3619fa 1 ion pplica ions pplica ion uresLTC3619 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 ................................................................2A 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) .................................... 40C 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 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 LTC3619EDD PBF LTC3619EDD TRPBF LFKM 10-Lead (3mm 3mm) Plastic DFN 40C to 85C LTC3619IDD PBF LTC3619IDD TRPBF LFKM 10-Lead (3mm 3mm) Plastic DFN 40C to 125C LTC3619EMSE PBF LTC3619EMSE TRPBF LTFKN 10-Lead Plastic MSOP 40C to 85C LTC3619IMSE PBF LTC3619IMSE TRPBF LTFKN 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. 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