Datasheet LTC3780 (Analog Devices)

LTC3780 High Efficiency, Synchronous, 4-Switch Buck-Boost Controller
FEATURES DESCRIPTION
n
Single Inductor Architecture Allows VIN Above,
The LTC®3780 is a high performance buck-boost switch-
Below or Equal to VOUT
ing regulator controller that operates from input voltages n
Wide VIN Range: 4V to 36V Operation
above, below or equal to the output voltage. The constant 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 < VOUT < 30V
30V (36V maximum) input and output range and seamless 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 VOUT Disconnected from VIN During Shutdown 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.
APPLICATIONS
Fault protection is provided by an output overvoltage 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 V OUT IN 12V
Efficiency and Power Loss
5V TO 32V 22µF + 100µF + 330µF 5A
V
50V 4.7µF 1µF 16V
OUT = 12V, ILOAD = 5A
CER 16V CER A V CER IN PGOOD INTVCC D 100 10 TG2 TG1 9 0.1µF 0.1µF BOOST2 BOOST1 95 8 SW2 SW1 POWER LOSS (W) B C 7 LTC3780 90 BG2 BG1 6 PLLIN I 85 5 TH 2200pF RUN 105k SS ON/OFF 1% 4 20k 0.1µF VOSENSE EFFICIENCY (%) 80 3 SGND FCB 7.5k SENSE+ SENSE– PGND 1% 75 2 1 70 0 0 5 10 15 20 25 30 35 0.010Ω VIN (V) 3780 TA01b 4.7µH 3780 TA01 Rev G Document Feedback For more information www.analog.com 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Block Diagram Operation Applications Information Typical Application Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Typical Application Related Parts