LTC3441 High Current Micropower Synchronous Buck-Boost DC/DC Converter Fea T Descrip T n Regulated Output with Input Above, Below or Equal The LTC 3441 is a high efficiency, fixed frequency, buck- to the Output boost DC/DC converter that operates efficiently from input n Single Inductor, No Schottky Diodes voltages above, below or equal to the output voltage. The n High Efficiency: Up to 95% topology incorporated in the IC provides a continuous n 25A Quiescent Current in Burst Mode Operation transfer function through all operating modes, making n Up to 1.2A Continuous Output Current from a Single the product ideal for single lithium ion or multicell ap- Lithium-Ion plications where the output voltage is within the battery n True Output Disconnect in Shutdown voltage range. n 2.4V to 5.5V Input Range The device includes two 0.10 N-channel MOSFET n 2.4V to 5.25V Output Range switches and two 0.11 P-channel switches. External n 1MHz Fixed Frequency Operation Schottky diodes are optional, and can be used for a mod- n Synchronizable Oscillator erate efficiency improvement. The operating frequency n Selectable Burst Mode or Fixed Frequency Operation is internally set to 1MHz and can be synchronized up to n <1A Quiescent Current in Shutdown 1.7MHz. Quiescent current is only 25A in Burst Mode n Small, Thermally Enhanced 12-Lead (4mm 3mm) operation, maximizing battery life in portable applica- DFN package tions. Burst Mode operation is user controlled and can be enabled by driving the MODE/SYNC pin high. If the MODE/SYNC pin is driven low or with a clock, then fixed a T frequency switching is enabled. n Handheld Computers Other features include a 1A shutdown, soft-start control, n Handheld Instruments thermal shutdown and current limit. The LTC3441 is n MP3 Players available in a thermally enhanced 12-lead (4mm 3mm) n Digital Cameras DFN package. L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical a T Li-Ion to 3.3V at 1A Buck-Boost Converter Efficiency vs V IN 100 L1 V = 3.3V OUT I = 200mA OUT 4.7H 95 V OUT 3.3V 90 1A 4 5 SW1 SW2 85 340k I = 1A 9 8 OUT PV V 80 IN OUT 2.5V TO 4.2V 10 LTC3441 12 V FB 75 IN C OUT 15k 1 11 22F SHDN/SS V 70 C 7 2 * MODE/SYNC GND 1.5nF 65 Li-Ion C IN 3 6 200k 10F PGND PGND 60 55 50 *1 = Burst Mode OPERATION C : TAIYO YUDEN JMK212BJ106MG IN 3441 TA01 2.5 3 3.5 4 4.5 5 5.5 0 = FIXED FREQUENCY C : TAIYO YUDEN JMK325BJ226MM OUT L1: TOKO A916CY-4R7M V (V) IN 3441 TA02 3441fc 1 For more information www.linear.com/LTC3441 EFFICIENCY (%) ion pplica ions pplica ion uresLTC3441 a Te Maxi Mu M r a T p in c F T (Note 1) TOP VIEW V , V Voltage ....................................... 0.3V to 6V IN OUT SHDN/SS 1 12 FB SW1, SW2 Voltage GND 2 11 V DC ............................................................ 0.3V to 6V C PGND 3 10 V IN Pulsed < 100ns ....................................... 0.3V to 7V 13 SW1 4 9 PV IN SHDN/SS, MODE/SYNC Voltage ................ 0.3V to 6V SW2 5 8 V OUT Operating Temperature Range (Note 2) .. 40C to 85C PGND 6 7 MODE/SYNC Maximum Junction Temperature (Note 4)............. 125C Storage Temperature Range .................. 65C to 125C DE12 PACKAGE 12-LEAD (4mm 3mm) PLASTIC DFN T = 125C JMAX = 53C/W 1-LAYER BOARD, = 43C/W 4-LAYER BOARD JA JA = 4.3C/W, EXPOSED PAD IS PGND (PIN 13) JC MUST BE SOLDERED TO PCB o r Der i n F Ma T