Analog Devices LTC2311

Description

The LTC®7813 is a high performance synchronousBoost+Buck DC/DC switching regulator controller thatdrives all N-channel power MOSFET stages. It containsindependent step-up (boost) and step-down (buck)controllers that can regulate two separate outputs or becascaded to regulate an output voltage from an inputvoltage that can be above, below, or equal to the outputvoltage. The LTC7813 operates from a wide 4.5V to 60Vinput supply range. When biased from the output of theboost regulator, the LTC7813 can operate from an inputsupply as low as 2.2V after start-up. The 34μA no-loadquiescent current (both channels on) extends operatingruntime in battery-powered systems.Unlike conventional buck-boost regulators, the LTC7813’scascaded Boost+Buck solution has continuous, nonpulsating,input and output currents, substantially reducingvoltage ripple and EMI. The LTC7813 has independentfeedback and compensation points for the boost and buckregulation loops, enabling a fast output transient response that can be externally optimized.

Features

nn Synchronous Boost and Buck Controllersnn When Cascaded, Allows VIN Above, Below, or Equalto Regulated VOUT of Up to 60Vnn Wide Bias Input Voltage Range: 4.5V to 60Vnn Output Remains in Regulation Through Input Dips(e.g. Cold Crank) Down to 2.2Vnn Adjustable Gate Drive Level 5V to 10V (OPTI-DRIVE)nn Low EMI with Low Input and Output Ripplenn Fast Output Transient Responsenn No External Bootstrap Diodes Requirednn High Light Load Efficiencynn Low Operating IQ: 29μA (One Channel On)nn Low Operating IQ: 34μA (Both Channels On)nn RSENSE or Lossless DCR Current Sensingnn Buck Output Voltage Range: 0.8V ≤ VOUT ≤ 60Vnn Boost Output Voltage Up 60Vnn Phase-Lockable Frequency (75kHz to 850kHz)nn Small 32-Pin 5mm × 5mm QFN Package

Typical applications

• High Power Battery Operated Systems
• Automotive and Industrial Power Systems