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LTC3891 - Low IQ, 60V Synchronous Step-Down Controller

Features

  • 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

Typical Application

LTC3891 Typical Application
LTC3891 Typical Application

Description

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.

Packaging

For complete and up to date package information and drawings, please refer to our packaging page

QFN-20, TSSOP-20

LTC3891 Package Drawing
LTC3891 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LTC3891EFE#PBF TSSOP 20 E $5.22 $3.65 View
LTC3891EFE#TRPBF TSSOP 20 E $3.71 View
LTC3891EUDC#PBF QFN 20 E $4.96 $3.47 View
LTC3891EUDC#TRPBF QFN 20 E $3.53 View
LTC3891HFE#PBF TSSOP 20 H $6.39 $4.47 View
LTC3891HFE#TRPBF TSSOP 20 H $4.53 View
LTC3891HUDC#PBF QFN 20 H $6.10 $4.27 View
LTC3891HUDC#TRPBF QFN 20 H $4.33 View
LTC3891IFE#PBF TSSOP 20 I $5.97 $4.18 View
LTC3891IFE#TRPBF TSSOP 20 I $4.24 View
LTC3891IUDC#PBF QFN 20 I $5.69 $3.98 View
LTC3891IUDC#TRPBF QFN 20 I $4.04 View
LTC3891MPFE#PBF TSSOP 20 MP $15.64 $10.95 View
LTC3891MPFE#TRPBF TSSOP 20 MP $11.01 View
LTC3891MPUDC#PBF QFN 20 MP $15.00 $10.50 View
LTC3891MPUDC#TRPBF QFN 20 MP $10.56 View
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC1695A OBSOLETE PLEASE USE DC1695B Contact Factory
DC1695B LTC3891EFE Demo Board | 4.5V < VIN < 60V; VOUT = 3 $150.00
DC1940A LTC3891EUDC Demo Board: 16V to 60V input to 12V ou $175.00
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Click here to view our complete list of demo boards

Applications

  • Automotive Always-On Systems
  • Battery Powered Digital Devices
  • Distributed DC Power Systems

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LTC3891

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