Features and Benefits

• Wide VIN Range: 4V to 60V (65V Abs Max)

• Low Operating IQ: 50μA

• Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 24V

• RSENSE or DCR Current Sensing

• Phase-Lockable Frequency (75kHz to 750kHz)

• Programmable Fixed Frequency (50kHz to 900kHz)

• Selectable Continuous, Pulse-Skipping or Low Ripple Burst Mode® Operation at Light Load

• Selectable Current Limit

• Very Low Dropout Operation: 99% Duty Cycle

• Adjustable Output Voltage Soft-Start or Tracking

• Power Good Output Voltage Monitor

• Output Overvoltage Protection

• Low Shutdown IQ: < 14μA

• Internal LDO Powers Gate Drive from VIN or EXTVCC

• No Current Foldback During Start-Up

• Small 20-Pin 3mm × 4mm QFN and TSSOP Packages

Product details

The LTC3891 is a high performance step-down switching regulator DC/DC 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.

The 50μA 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 LTC3891 features a precision 0.8V reference and power good output indicator. A wide 4V to 60V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries. The output voltage of the LTC3891 can be programmed between 0.8V to 24V.

The TRACK/SS pin ramps 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 conduction mode at light loads.

Applications

• Automotive Always-On Systems

• Battery Powered Digital Devices

• Distributed DC Power Systems