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  2. Power Management
  3. Switching Regulators
  4. Step-Down (Buck) Regulators
  5. High Input Voltage Buck Regulators
  6. LTC3891


Overview

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

Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Evaluation Kits (2)

Tools & Simulations

LTspice

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

To launch ready-to-run LTspice demonstration circuits for this part:

Step 1: Download and install LTspice on your computer.

Step 2: Click on the link in the section below to download a demonstration circuit.

Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.

LTspice

Models for the following parts are available in LTspice:

LTC3891

LTpowerCAD

LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.

To open the project file for this circuit:

Step 1: Download and install LTpowerCAD on your computer.

Step 2: Click on the link(s) in the section below to download part-specific project files.

Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.

LTPowerCAD

Design tools for the following parts are available in LTpowerCAD:

LTC3891

Product Recommendations

LTC3891 Companion Parts

Recommended Related Parts

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.

Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
LTC3891EFE#PBF Material Declaration Reliability Data 20-Lead TSSOP w/ EP
LTC3891EFE#TRPBF Material Declaration Reliability Data 20-Lead TSSOP w/ EP
LTC3891EUDC#PBF Material Declaration Reliability Data 20-Lead QFN (3mm x 4mm x 0.75mm w/ EP)
LTC3891EUDC#TRPBF Material Declaration Reliability Data 20-Lead QFN (3mm x 4mm x 0.75mm w/ EP)
LTC3891HFE#PBF Material Declaration Reliability Data 20-Lead TSSOP w/ EP
LTC3891HFE#TRPBF Material Declaration Reliability Data 20-Lead TSSOP w/ EP
LTC3891HUDC#PBF Material Declaration Reliability Data 20-Lead QFN (3mm x 4mm x 0.75mm w/ EP)
LTC3891HUDC#TRPBF Material Declaration Reliability Data 20-Lead QFN (3mm x 4mm x 0.75mm w/ EP)
LTC3891IFE#PBF Material Declaration Reliability Data 20-Lead TSSOP w/ EP
LTC3891IFE#TRPBF Material Declaration Reliability Data 20-Lead TSSOP w/ EP
LTC3891IUDC#PBF Material Declaration Reliability Data 20-Lead QFN (3mm x 4mm x 0.75mm w/ EP)
LTC3891IUDC#TRPBF Material Declaration Reliability Data 20-Lead QFN (3mm x 4mm x 0.75mm w/ EP)
LTC3891MPFE#PBF Material Declaration Reliability Data 20-Lead TSSOP w/ EP
LTC3891MPFE#TRPBF Material Declaration Reliability Data 20-Lead TSSOP w/ EP
LTC3891MPUDC#PBF Material Declaration Reliability Data 20-Lead QFN (3mm x 4mm x 0.75mm w/ EP)
LTC3891MPUDC#TRPBF Material Declaration Reliability Data 20-Lead QFN (3mm x 4mm x 0.75mm w/ EP)
Wafer Fabrication Data R526 Reliability Data

PCN-PDN Information

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Sample & Buy


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Buy Now Pricing


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List Pricing


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Lead Times


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Sampling


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Price Table Help

 

Evaluation Boards

Pricing displayed is based on 1-piece.

Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.