POWER LOSS (W) LTC3411A 1.25A, 4MHz, Synchronous Step-Down DC/DC Converter FEATURES DESCRIPTION n Uses Tiny Capacitors and Inductor The LTC 3411A is a constant frequency, synchronous n High Frequency Operation: Up to 4MHz step-down DC/DC converter. Intended for medium power n Low R Internal Switches: 0.15 applications, it operates from a 2.5V to 5.5V input voltage DS(ON) n High Efficiency: Up to 96% range and has a user configurable operating frequency up n Selectable Low Ripple (25mV ) Burst Mode to 4MHz, allowing the use of tiny, low cost capacitors and P-P Operation: I = 40A inductors 1mm or less in height. The output voltage is Q n Stable with Ceramic Capacitors adjustable from 0.8V to 5.5V. Internal synchronous power n Current Mode Operation for Excellent Line and Load switches provide high efficiency. The LTC3411As current Transient Response mode architecture and external compensation allow the n Short-Circuit Protected transient response to be optimized over a wide range of n Low Dropout Operation: 100% Duty Cycle loads and output capacitors. n Low Shutdown Current: I 1A Q The LTC3411A can be configured for automatic power n Output Voltages from 0.8V to 5V saving Burst Mode operation (I = 40A) to reduce gate Q n Synchronizable to External Clock charge losses when the load current drops below the level n Supports Prebiased Outputs required for continuous operation. For reduced noise and n Small 10-Lead 3mm 3mm DFN or MSOP Package RF interference, the SYNC/MODE pin can be configured to skip pulses or provide forced continuous operation. APPLICATIONS To further maximize battery life, the P-channel MOSFET n Notebook Computers is turned on continuously in dropout (100% duty cycle). n Digital Cameras In shutdown, the device draws <1A. n Cellular Phones All registered trademarks and trademarks are the property of their respective owners. Protected n by U.S. patents, including 5481178, 6580258, 6498466, 6611131.. Handheld Instruments n Board Mounted Power Supplies TYPICAL APPLICATION Efficiency and Power Loss vs Output Current Step-Down 2.5V/1.25A Regulator 100 1 V IN 2.5V TO 5.5V 90 80 10F 0.1 70 SYNC SYNC/MODE PV IN 60 PGOOD SV IN 2.2H V OUT 50 0.01 SW 2.5V LTC3411A 1.25A 22pF 40 30 0.001 I 22F TH V = 2.7V 887k 20 IN V = 3.6V SHDN/R V T FB IN 12.1k 10 V = 4.2V IN SGND PGND 0 0.0001 549k 412k 680pF 0.1 1 10 100 1000 10000 OUTPUT CURRENT (mA) 3411a TA01a f = 1MHz O 3411A TA01b Burst Mode OPERATION Rev. E 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LTC3411A ABSOLUTE MAXIMUM RATINGS (Note 1) PV , SV Voltages .................................... 0.3V to 6V Operating Junction Temperature Range IN IN V , I , SHDN/R Voltages ......... 0.3V to (V + 0.3V) (Notes 2, 5, 8) ........................................ 40C to 125C FB TH T IN SYNC/MODE Voltage ................... 0.3V to (V + 0.3V) Storage Temperature Range .................. 65C to 125C IN SW Voltage ................................. 0.3V to (V + 0.3V) Lead Temperature IN PGOOD Voltage ............................ 0.3V to (V + 0.3V) (MS Package Soldering, 10 sec) ...........................300C IN PIN CONFIGURATION TOP VIEW TOP VIEW SHDN/R 1 10 I T TH SHDN/R 1 10 I T TH SYNC/MODE 2 9 V FB SYNC/MODE 2 9 V FB 11 SGND 3 8 PGOOD SGND 3 8 PGOOD SW 4 7 SV SW 4 7 SV IN IN PGND 5 6 PV IN PGND 5 6 PV IN MS PACKAGE 10-LEAD PLASTIC MSOP DD PACKAGE 10-LEAD (3mm 3mm) PLASTIC DFN T = 125C, = 120C/W JMAX JA T = 125C, = 43C/W JMAX JA EXPOSED PAD (PIN 11) IS PGND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3411AEDD PBF LTC3411AEDD TRPBF LAJM 10-Lead (3mm 3mm) Plastic DFN 40C to 125C LTC3411AIDD PBF LTC3411AIDD TRPBF LAJM 10-Lead (3mm 3mm) Plastic DFN 40C to 125C LTC3411AEMS PBF LTC3411AEMS TRPBF LTAJK 10-Lead Plastic MSOP 40C to 125C LTC3411AIMS PBF LTC3411AIMS TRPBF LTAJK 10-Lead Plastic MSOP 40C to 125C Contact the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with TRMPBF suffix. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at T = 25C, V = 3.6V, R = 125k unless otherwise specified. (Note 2) A IN T SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Operating Voltage Range l 2.5 5.5 V IN I Feedback Pin Input Current (Note 3) 0.1 A FB l V Feedback Voltage (Note 3) 0.784 0.8 0.816 V FB V Reference Voltage Line Regulation V = 2.5V to 5.5V 0.04 0.2 %/V LINEREG IN l V Output Voltage Load Regulation I = 0.55V to 0.9V 0.02 0.2 % LOADREG TH g Error Amplifier Transconductance I Pin Load = 5A (Note 3) 300 S m(EA) TH Rev. E 2 For more information www.analog.com