Features

• Single Inductor Architecture Allows V_IN Above, Below or Equal to V_OUT
• Wide V_IN Range: 4V to 36V Operation
• Synchronous Rectification: Up to 98% Efficiency
• Current Mode Control
• ±1% Output Voltage Accuracy: 0.8V < V_OUT < 30V
• Phase-Lockable Fixed Frequency: 200kHz to 400kHz
• Power Good Output Voltage Monitor
• Internal LDO for MOSFET Supply
• Quad N-Channel MOSFET Synchronous Drive
• V_OUT Disconnected from V_IN 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 Packages

Typical Application

Description

The LTC3780 is a high performance buck-boost switching regulator controller that operates from input voltages above, below or equal to the output voltage. The constant frequency current mode architecture allows a phase-lockable frequency of up to 400kHz. With a wide 4V to 30V (36V maximum) input and output range and seamless transfers between operating modes, the LTC3780 is ideal for automotive, telecom and battery-powered systems.

The operating mode of the controller is determined through the FCB pin. For boost operation, the FCB mode pin can select among Burst Mode® operation, Discontinuous mode and Forced Continuous mode. During buck operation, the FCB mode pin can select among Skip-Cycle mode, Discontinuous mode and Forced Continuous mode. Burst Mode operation and Skip-Cycle mode provide high efficiency operation at light loads while forced continuous mode and discontinuous mode operate at a constant frequency.

Fault protection is provided by an output overvoltage comparator and internal foldback current limiting. A Power Good output pin indicates when the output is within 7.5% of its designed set point.

Protected by U.S. Patents, including 5481178, 6304066, 5929620, 5408150, 6580258, patent pending on current mode architecture and protection