Features

• Synchronous Boost and Buck Controllers
• When Cascaded, Allows V_IN Above, Below, or Equal to Regulated V_OUT of Up to 60V
• Wide Bias Input Voltage Range: 4.5V to 60V
• Output Remains in Regulation Through Input Dips (e.g. Cold Crank) Down to 2.2V
• Adjustable Gate Drive Level 5V to 10V (OPTI-DRIVE)
• Low EMI with Low Input and Output Ripple
• Fast Output Transient Response
• No External Bootstrap Diodes Required
• High Light Load Efficiency
• Low Operating I_Q: 29μA (One Channel On)
• Low Operating I_Q: 34μA (Both Channels On)
• R_SENSE or Lossless DCR Current Sensing
• Buck Output Voltage Range: 0.8V ≤ V_OUT ≤ 60V
• Boost Output Voltage Up 60V
• Phase-Lockable Frequency (75kHz to 850kHz)
• Small 32-Pin 5mm × 5mm QFN Package

Typical Application

Description

The LTC®7813 is a high performance synchronous Boost+Buck DC/DC switching regulator controller that drives all N-channel power MOSFET stages. It contains independent step-up (boost) and step-down (buck) controllers that can regulate two separate outputs or be cascaded to regulate an output voltage from an input voltage that can be above, below, or equal to the output voltage. The LTC7813 operates from a wide 4.5V to 60V input supply range. When biased from the output of the boost regulator, the LTC7813 can operate from an input supply as low as 2.2V after start-up. The 34μA no-load quiescent current (both channels on) extends operating runtime in battery-powered systems.

Unlike conventional buck-boost regulators, the LTC7813’s cascaded Boost+Buck solution has continuous, nonpulsating, input and output currents, substantially reducing voltage ripple and EMI. The LTC7813 has independent feedback and compensation points for the boost and buck regulation loops, enabling a fast output transient response that can be externally optimized.