0
LTC3851A-1
  • LTC3851A-1
  • LTC3851A-1
  • LTC3851A-1
  • LTC3851A-1

LTC3851A-1

PRODUCTION

Synchronous Step-Down Switching Regulator Controller

Analog Devices LTC3851A-1 Product Info

10 February 2026 4

Features

  • Wide VIN Range: 4V to 38V Operation
  • RSENSE or DCR Current Sensing
  • ±1% Output Voltage Accuracy
  • Power Good Output Voltage Monitor
  • 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
  • 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 or 3mm × 3mm QFN Package

Part details & applications

The LTC3851A-1 is a high performance synchronous step-down switching regulator controller that drives an all N-channel synchronous power MOSFET stage. A constant frequency current mode architecture allows a phase-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-1 features a precision 0.8V reference and a power good indicator. A wide 4V to 38V (40V absolute maximum) input supply range encompasses most battery configurations and intermediate bus voltages.

The TK/SS pin ramps the output voltage during start-up and shutdown with coincident or ratiometric tracking. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The MODE/PLLIN pin selects among Burst Mode operation, pulse-skipping mode or continuous inductor current mode at light loads and allows the IC to be synchronized to an external clock. The LTC3851A-1 contains an improved PLL compared to the LTC3851-1.

The LTC3851A-1 is identical to the LTC3851A except that the ILIM pin is replaced by PGOOD.