Power by Linear™ / Analog Devices' LTC3859 is a high-performance triple output (buck/buck/boost) synchronous DC/DC switching regulator controller. This controller drives all N-channel power MOSFET stages. Constant frequency current mode architecture allows a phase-lockable switching frequency of up to 850 kHz. The LTC3859 operates from a wide 4.5 V to 38 V input supply range. When biased from the output of the boost converter or another auxiliary supply, the LTC3859 can operate from an input supply as low as 2.5 V after start-up.The 55 μA no-load quiescent current extends operating run-time in battery powered systems. OPTI-LOOP® compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3859 features a precision 0.8 V reference for the bucks, 1.2 V reference for the boost, and a power good output indicator.Independent TRACK/SS pins for each controller ramp the output voltages during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The PLLIN/MODE pin selects among Burst Mode® operation, pulse-skipping mode, or continuous inductor current mode at light loads.This controller has an operating temperature range of -40°C to +125°C and +150°C and comes in QFN or TSSOP packages. The LTC3859 is perfect for distributed power supplies, battery powered, and automotive power systems.<strong>Features:</strong> Boost output voltage up to 60 V, Buck output voltage range: 0.8 V ≤ VOUT ≤ 24 V, Dual buck plus single boost synchronous controllers, Outputs remain in regulation through cold crank down to 2.5 V, Operating IQ: 55 μA (one channel on), Bias input voltage range: 4.5 V to 38 V, RSENSE or DCR current sensing, 100% duty cycle for boost synchronous MOSFET, Phase-lockable frequency (75 kHz to 850 kHz), Programmable fixed frequency (50 kHz to 900 kHz), Selectable continuous, pulse-skipping, or low ripple Burst Mode operation at light loads, Low buck dropout operation: 99% duty cycle, Adjustable output voltage soft-start or tracking, Shutdown IQ: 14 μA, Distributed power supplies, Battery powered, Automotive power systems
Feature
- 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
