LTC3859A

LTC3859A Low IQ, Triple Output, Buck/Buck/Boost Synchronous Controller with Improved Burst Mode Operation FEATURES DESCRIPTION n Dual Buck Plus Single Boost Synchronous Controllers n Outputs Remain in Regulation Through Cold Crank Down to 2.5V n Low Operating IQ: 55μA (One Channel On) n Wide Bias Input Voltage Range: 4.5V to 38V n Buck Output Voltage Range: 0.8V ≤ VOUT ≤ 24V n Boost Output Voltage Up to 60V n RSENSE or DCR Current Sensing n 100% Duty Cycle for Boost Synchronous MOSFET Even in Burst Mode® Operation n Phase-Lockable Frequency (75kHz to 850kHz) n Programmable Fixed Frequency (50kHz to 900kHz) n Selectable Continuous, Pulse-Skipping or Low Ripple Burst Mode Operation at Light Loads n Very Low Buck Dropout Operation: 99% Duty Cycle n Adjustable Output Voltage Soft-Start or Tracking n Low Shutdown IQ: 14μA n Small 38-Pin 5mm × 7mm QFN and TSSOP Packages APPLICATIONS n Automotive Always-On and Start-Stop Systems n Battery Operated Digital Devices n Distributed DC Power Systems n Multioutput Buck-Boost Applications The LTC®3859A is a high performance triple output (buck/ buck/boost) synchronous DC/DC switching regulator controller that drives all N-channel power MOSFET stages. Constant frequency current mode architecture allows a phase-lockable switching frequency of up to 850kHz. The LTC3859A operates from a wide 4.5V to 38V input supply range. When biased from the output of the boost converter or another auxiliary supply, the LTC3859A can operate from an inpu...