Analog Devices LTC3851A-1

Description

The LTC®3851A is a high performance synchronousstep-down switching regulator controller that drivesan all N-channel synchronous power MOSFET stage. Aconstant frequency current mode architecture allows aphase‑lockable frequency of up to 750kHz. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3851A features a precision 0.8Vreference that is compatible with a wide 4V to 38V inputsupply range. The TK/SS pin ramps the output voltage during start‑up.Current foldback limits MOSFET heat dissipation duringshort-circuit conditions. The MODE/PLLIN pin selectsamong Burst Mode operation, pulse-skipping mode orcontinuous inductor current mode at light loads and allowsthe IC to be synchronized to an external clock. TheLTC3851A contains an improved PLL compared to theLTC3851.The LTC3851A-1 is a version with a power good outputsignal instead of adjustable current limit.

Features

• Wide VIN Range: 4V to 38V Operation
• RSENSE or DCR Current Sensing
• ±1% Output Voltage Accuracy
• Phase-Lockable Fixed Frequency: 250kHz to 750kHz
• Dual N-Channel MOSFET Synchronous Drive
• Very Low Dropout Operation: 99% Duty Cycle
• Adjustable Output Voltage Soft-Start or Tracking
• Output Current Foldback Limiting
• Output Overvoltage Protection
• 5V Internal Regulator
• OPTI-LOOP® Compensation Minimizes COUT
• Selectable Continuous, Pulse-Skipping or Burst Mode® Operation at Light Loads
• Low Shutdown IQ: 20μA
• VOUT Range: 0.8V to 5.5V
• Thermally Enhanced 16-Lead MSOP, 16-Lead Narrow SSOP or 3mm × 3mm QFN Package

Typical applications

• Distributed DC Power Systems
• Automotive Systems
• Telecom Systems
• Industrial Equipment

More information

• IC product information