Features: . Single Inductor Architecture Allows VIN Above,
Below or Equal to VOUT
. Wide VIN Range: 4V to 36V Operation
. Synchronous Rectification: Up to 98% Efficiency
. Current Mode Control
. ±1% Output Voltage Accuracy: 0.8V < VOUT < 30V
. Phase-Lockable Fixed Frequency: 200kHz to 400kHz
. Power Good Output Voltage Monitor
. Internal LDO for MOSFET Supply
. Quad N-Channel MOSFET Synchronous Drive
. VOUT Disconnected from VIN During Shutdown
. Adjustable Soft-Start Current Ramping
. Foldback Output Current Limiting
. Selectable Low Current Modes
. Output Overvoltage Protection
. Available in 24-Lead SSOP and Exposed Pad
(5mm × 5mm) 32-Lead QFN PackagesApplicationAutomotive Systems
Telecom Systems
DC Power Distribution Systems
High Power Battery-Operated Devices
Industrial ControlPinout
SpecificationsInput Supply Voltage (VIN)........................ 0.3V to 36V
Topside Driver Voltages
(BOOST1, BOOST2).................................... 0.3V to 42V
Switch Voltage (SW1, SW2).......................... 5V to 36V
INTVCC, EXTVCC, RUN, SS, (BOOST SW1),
(BOOST2 SW2), PGOOD............................ 0.3V to 7V
PLLIN Voltage........................................... 0.3V to 5.5V
PLLFLTR Voltage........................................0.3V to 2.7V
FCB, STBYMD Voltages......................... 0.3V to INTVCC
ITH, VOSENSE Voltages............................ 0.3V to 2.4V
Peak Output Current <10ms (TG1, TG2, BG1, BG2).....3A
INTVCC Peak Output Current................................ 40mA
Operating Temperature Range (Note 7)
LTC3780E................................................40°C to 85°C
LTC3780I.................................................40°C to 85°C
Junction Temperature (Note 2)............................. 125°C
Storage Temperature Range..................65°C to 125°C
Lead Temperature (Soldering, 10 sec)
SSOP Only..............................................................300°C
DescriptionThe LTC®3780 is a high performance buck-boost switch-ing regulator controller that operates from input voltagesabove, below or equal to the output voltage. The constantfrequency current mode architecture allows a phase-lockable frequency of up to 400kHz. With a wide 4V to 30V(36Vmaximum) input and output range and seamlesstransfers between operating modes, the LTC3780 is idealfor automotive, telecom and battery-powered systems.
The operating mode of the controller of LTC3780 is determined throughthe FCB pin. For boost operation, the FCB mode pin canselect among BurstMode® operation, Discontinuous modeand Forced Continuous mode. During buck operation, theFCB mode pin can select among Skip-Cycle mode, Discon-tinuous mode and Forced Continuous mode. Burst Modeoperation and Skip-Cycle mode provide high efficiencyoperation at light loads while Forced Continuous modeand Discontinuous mode operate at a constant frequency.
Fault protection of LTC3780 is provided by an output overvoltagecomparator and internal foldback current limiting. A PowerGood output pin indicates when the output is within 7.5%of its designed set point.
LTC3780 Data Sheet
