Small Footprint, Wide V Range Synchronous Step-Down DC/DC Controller

The LTC3854 is a high performance synchronous stepdown switching DC/DC controller that drives an all N-channel synchronous power MOSFET stage.

The LTC3854 features a 400kHz constant frequency current mode architecture. The LTC3854 operates from a 4.5V to 38V (40V absolute maximum) input voltage range and regulates the output voltage from 0.8V to 5.5V.

The RUN/SS pin provides both soft-start and enable features. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. Current foldback limits MOSFET dissipation during short circuit conditions. Current foldback functions are disabled during soft-start.

The LTC3854 has a minimum on-time at 75ns, making it well suited for high step-down ratios. The strong onboard MOSFET drivers allow the use of high power external MOSFETs to produce output currents up to 20A.

Applications

* Automotive Systems

* Telecom Systems

* Industrial Equipment

* Distributed DC Power Systems

* Wide Operating VIN Range: 4.5V to 38V

* RSENSE or DCR Current Sensing

* ±1% 0.8V Reference Accuracy Over Temperature

* 400kHz Switching Frequency

* Dual N-channel MOSFET Synchronous Drive

* Very Low Dropout Operation: 97% Duty Cycle

* Starts Up Into Pre-Biased Output

* Adjustable Output Voltage Soft-Start

* Output Current Foldback Limiting (Disabled During Soft-Start)

* Output Overvoltage Protection

* 5V LDO for External Gate Drive

* OPTI-LOOP® Compensation Minimizes COUT

* Low Shutdown IQ: 15μA

* Tiny Thermally Enhanced 12-Pin 2mm × 3mm DFN and MSOP Packages