Description
The LTC®3859AL 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 LTC3859AL 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 LTC3859AL can operate from an input supply as low as 2.5V after start-up.

FEATUREs
Low Operating IQ: 28μA (One Channel On)
Dual Buck Plus Single Boost Synchronous Controllers
Outputs Remain in Regulation Through Cold Crank Down to 2.5V
Wide Bias Input Voltage Range: 4.5V to 38V
Buck Output Voltage Range: 0.8V ≤ VOUT ≤ 24V
Boost Output Voltage Up to 60V
RSENSE or DCR Current Sensing
100% Duty Cycle for Boost Synchronous MOSFET Even in Burst Mode® Operation
Phase-Lockable Frequency (75kHz to 850kHz)
Programmable Fixed Frequency (50kHz to 900kHz)
Selectable Continuous, Pulse-Skipping or Low Ripple Burst Mode Operation at Light Loads
Very Low Buck Dropout Operation: 99% Duty Cycle
Adjustable Output Voltage Soft-Start or Tracking
Low Shutdown IQ: 10μA
Small 38-Lead 5mm × 7mm QFN and TSSOP Packages

APPLICATIONs
Automotive Always-On and Start-Stop Systems
Battery Operated Digital Devices
Distributed DC Power Systems
Multioutput Buck-Boost Applications