Power Management Switching Regulator Step-Down (Buck) Regulators Multiple Output Buck
Power Management Switching Regulator Step-Down (Buck) Regulators Micropower Buck
 Power Management Switching Regulator Step-Down (Buck) Regulators External Power Switch Buck Controllers
 Power Management Switching Regulator Step-Up (Boost) Regulators External Power Switch Boost

For New Designs

LTC3859AL - Triple Output, Buck/Buck/Boost Synchronous Controller with 28μA Burst Mode IQ

LTC2955 - Pushbutton On/Off Controller with Automatic Turn-On

LTC2960 - 36V Nano-Current Two Input Voltage Monitor

LTC3859 - Low IQ, Triple Output, Buck/Buck/Boost Synchronous Controller

Features

  • Dual Buck Plus Single Boost Synchronous Controllers
  • Outputs Remain in Regulation Through Cold Crank Down to 2.5V
  • Low Operating IQ: 55μA (One Channel On)
  • Wide Bias Input Voltage Range: 4.5V to 38V
  • Buck Output Voltage Range: 0.8V ≤ VOUT ≤ 24V
  • Boost Output Voltage Up to 60V
  • RSENSE or DCR Current Sensing
  • 100% Duty Cycle for Boost Synchronous MOSFET
  • Phase-Lockable Frequency (75kHz to 850kHz)
  • Programmable Fixed Frequency (50kHz to 900kHz)
  • Selectable Continuous, Pulse-Skipping or Low Ripple Burst Mode® Operation at Light Loads
  • Very Low Buck Dropout Operation: 99% Duty Cycle
  • Adjustable Output Voltage Soft-Start or Tracking
  • Low Shutdown IQ: 14μA
  • Small 38-Pin 5mm x 7mm QFN and TSSOP Packages

Typical Application

LTC3859 Typical Application
LTC3859 Typical Application

Description

The LTC®3859 is a high performance triple output (buck/ buck/boost) synchronous DC/DC switching regulator controller that drives all N-channel power MOSFET stages. Constant frequency current mode architecture allows a phase-lockable switching frequency of up to 850kHz. The LTC3859 operates from a wide 4.5V to 38V input supply range. When biased from the output of the boost converter or another auxiliary supply, the LTC3859 can operate from an input supply as low as 2.5V after start-up.

The 55μA no-load quiescent current extends operating runtime 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 LTC3859 features a precision 0.8V reference for the bucks, 1.2V reference for the boost and a power good output indicator.

Independent TRACK/SS pins for each controller ramp 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 inductor current mode at light loads.

Packaging

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

QFN-38, TSSOP-38

LTC3859 Package Drawing
LTC3859 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LTC3859AEFE#PBF TSSOP 38 E $7.31 $5.12 View
LTC3859AEFE#TRPBF TSSOP 38 E $5.18 View
LTC3859AEUHF#PBF QFN 38 E $7.07 $4.95 View
LTC3859AEUHF#TRPBF QFN 38 E $5.01 View
LTC3859AHFE#PBF TSSOP 38 H $8.50 $5.95 View
LTC3859AHFE#TRPBF TSSOP 38 H $6.01 View
LTC3859AHUHF#PBF QFN 38 H $8.23 $5.76 View
LTC3859AHUHF#TRPBF QFN 38 H $5.82 View
LTC3859AIFE#PBF TSSOP 38 I $8.07 $5.65 View
LTC3859AIFE#TRPBF TSSOP 38 I $5.71 View
LTC3859AIUHF#PBF QFN 38 I $7.82 $5.47 View
LTC3859AIUHF#TRPBF QFN 36 I $5.53 View
LTC3859ALEFE#PBF TSSOP 38 E $7.31 $5.12 View
LTC3859ALEFE#TRPBF TSSOP 38 E $5.18 View
LTC3859ALEUHF#PBF QFN 38 E $7.07 $4.95 View
LTC3859ALEUHF#TRPBF QFN 38 E $5.01 View
LTC3859ALHFE#PBF TSSOP 38 H $8.50 $5.95 View
LTC3859ALHFE#TRPBF TSSOP 38 H $6.01 View
LTC3859ALHUHF#PBF QFN 38 H $8.23 $5.76 View
LTC3859ALHUHF#TRPBF QFN 38 H $5.82 View
LTC3859ALIFE#PBF TSSOP 38 I $7.82 $5.47 View
LTC3859ALIFE#TRPBF TSSOP 38 I $5.53 View
LTC3859ALIUHF#PBF QFN 38 I $7.82 $5.47 View
LTC3859ALIUHF#TRPBF QFN 38 I $5.53 View
LTC3859ALMPFE#PBF TSSOP 38 MP $21.36 $14.95 View
LTC3859ALMPFE#TRPBF TSSOP 38 MP $15.01 View
LTC3859ALMPUHF#PBF QFN 38 MP $21.09 $14.76 View
LTC3859ALMPUHF#TRPBF QFN 38 MP $14.82 View
LTC3859AMPFE#PBF TSSOP 38 MP $21.79 $15.25 View
LTC3859AMPFE#TRPBF TSSOP 38 MP $15.31 View
LTC3859AMPUHF#PBF QFN 38 MP $21.09 $14.76 View
LTC3859AMPUHF#TRPBF QFN 38 MP $14.82 View
LTC3859EFE#PBF TSSOP 38 E $7.31 $5.12 View
LTC3859EFE#TRPBF TSSOP 38 E $5.18 View
LTC3859EUHF#PBF QFN 38 E $7.07 $4.95 View
LTC3859EUHF#TRPBF QFN 38 E $5.01 View
LTC3859IFE#PBF TSSOP 38 I $8.07 $5.65 View
LTC3859IFE#TRPBF TSSOP 38 I $5.71 View
LTC3859IUHF#PBF QFN 38 I $7.82 $5.47 View
LTC3859IUHF#TRPBF QFN 38 I $5.53 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.

Click here to view our complete list of demo boards

Applications

  • Automotive Always-On and Start-Stop Systems
  • Battery Operated Digital Devices
  • Distributed DC Power Systems

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LTC3859

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