POWER LOSS (W) LTC3780 High Efficiency, Synchronous, 4-Switch Buck-Boost Controller FEATURES DESCRIPTION n Single Inductor Architecture Allows V Above, The LTC 3780 is a high performance buck-boost switch- IN Below or Equal to V ing regulator controller that operates from input voltages OUT n Wide V Range: 4V to 36V Operation above, below or equal to the output voltage. The constant IN n Synchronous Rectification: Up to 98% Efficiency frequency current mode architecture allows a phase- n Current Mode Control lockable frequency of up to 400kHz. With a wide 4V to n 1% Output Voltage Accuracy: 0.8V < V < 30V 30V (36V maximum) input and output range and seamless OUT n Phase-Lockable Fixed Frequency: 200kHz to 400kHz transfers between operating modes, the LTC3780 is ideal n Power Good Output Voltage Monitor for automotive, telecom and battery-powered systems. n Internal LDO for MOSFET Supply The operating mode of the controller is determined through n Quad N-Channel MOSFET Synchronous Drive the FCB pin. For boost operation, the FCB mode pin can n V Disconnected from V During Shutdown OUT IN select among Burst Mode operation, discontinuous mode n Adjustable Soft-Start Current Ramping and forced continuous mode. During buck operation, the n Foldback Output Current Limiting FCB mode pin can select among skip-cycle mode, discon- n Selectable Low Current Modes tinuous mode and forced continuous mode. Burst Mode n Output Overvoltage Protection operation and skip-cycle mode provide high efficiency n Available in 24-Lead SSOP and Exposed Pad operation at light loads while forced continuous mode (5mm 5mm) 32-Lead QFN Packages and discontinuous mode operate at a constant frequency. Fault protection is provided by an output overvoltage APPLICATIONS comparator and internal foldback current limiting. A power n Automotive Systems good output pin indicates when the output is within 7.5% n Telecom Systems of its designed set point. n DC Power Distribution Systems All registered trademarks and trademarks are the property of their respective owners. Protected n High Power Battery-Operated Devices by U.S. Patents, including 5481178, 6304066, 5929620, 5408150, 6580258, patent pending on current mode architecture and protection. n Industrial Control TYPICAL APPLICATION High Efficiency Buck-Boost Converter V OUT V IN Efficiency and Power Loss 12V 5V TO 32V 22F 100F + + 5A 330F 1F V = 12V, I = 5A 16V 50V 4.7F OUT LOAD 16V CER CER CER V A PGOOD INTV D IN CC 100 10 TG2 TG1 9 0.1F 0.1F 95 BOOST2 BOOST1 8 SW2 SW1 7 B C 90 LTC3780 6 BG2 BG1 PLLIN 5 85 I TH 105k 2200pF ON/OFF RUN SS 4 1% V 20k 0.1F OSENSE 80 3 SGND FCB 7.5k + 2 1% SENSE SENSE PGND 75 1 70 0 0 5 10 15 20 25 30 35 0.010 V (V) IN 3780 TA01b 4.7H 3780 TA01 Rev G 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LTC3780 ABSOLUTE MAXIMUM RATINGS (Note 1) Input Supply Voltage (V ) ........................ 0.3V to 36V I , V Voltages .............................. 0.3V to 2.4V IN TH OSENSE Topside Driver Voltages Peak Output Current <10s (TG1, TG2, BG1, BG2) ......3A (BOOST1, BOOST2)................................... 0.3V to 42V INTV Peak Output Current ................................. 40mA CC Switch Voltage (SW1, SW2) ......................... 5V to 36V Operating Junction Temperature Range (Notes 2, 7) INTV , EXTV , (BOOST SW1), LTC3780E ............................................40C to 85C CC CC (BOOST2 SW2), PGOOD .......................... 0.3V to 7V LTC3780I ........................................... 40C to 125C RUN, SS ....................................................... 0.3V to 6V LTC3780MP ....................................... 55C to 125C PLLIN Voltage .......................................... 0.3V to 5.5V Storage Temperature Range .................. 65C to 125C PLLFLTR Voltage ...................................... 0.3V to 2.7V Lead Temperature (Soldering, 10 sec) FCB, STBYMD Voltages ....................... 0.3V to INTV SSOP Only ........................................................300C CC PIN CONFIGURATION TOP VIEW TOP VIEW PGOOD 1 24 BOOST1 32 31 30 29 28 27 26 25 SS 2 23 TG1 + + SENSE 1 24 SW1 SENSE 3 22 SW1 SENSE 2 23 V IN 4 21 V SENSE IN I 3 22 EXTV TH CC 5 20 EXTV I CC TH V INTV 4 21 OSENSE CC 6 19 INTV V CC OSENSE 33 SGND 5 20 BG1 7 18 BG1 SGND RUN 6 19 PGND 8 17 PGND RUN FCB 7 18 BG2 9 16 BG2 FCB PLLFTR 8 17 SW2 10 15 SW2 PLLFLTR 9 10 11 12 13 14 15 16 11 14 TG2 PLLIN 12 13 BOOST2 STBYMD G PACKAGE UH PACKAGE 24-LEAD PLASTIC SSOP 32-LEAD (5mm 5mm) PLASTIC QFN T = 125C, = 130C/W JMAX JA T C, = 34C/W JMAX = 125 JA EXPOSED PAD (PIN 33) IS SGND, MUST BE SOLDERED TO PCB Rev G 2 For more information www.analog.com NC NC PLLIN SS STBYMD PGOOD NC NC NC NC BOOST2 BOOST1 TG2 TG1 NC NC