LTC3874 - PolyPhase Step-Down Synchronous Slave Controller with Sub-Milliohm DCR Sensing

Features

  • Phase Extender for High Phase Count Voltage Rails
  • Accurate Phase-to-Phase Current Sharing
  • Sub-Milliohm DCR Current Sensing
  • Phase-Lockable Fixed Frequency 250kHz to 1MHz
  • Immediate Response to Master IC's Fault
  • Up to 12 Phase Operation
  • Wide VIN Range: 4.5V to 38V
  • VOUT Range: Up to 3.5V (LOWDCR Pin = INTVCC)
    Up to 5.5V (LOWDCR Pin = OV)
  • Proprietary Current Mode Control Loop
  • Programmable CCM/DCM Operation
  • Programmable Phase Shift Control
  • Dual N-Channel MOSFET Gate Drivers
  • 28-Lead (4mm × 5mm) QFN Package
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LTC3874 Typical Application
LTC3874 Typical Application

Description

The LTC®3874 is a dual PolyPhase® current mode synchronous step-down slave controller. It enables high current, multi-phase applications when paired with a companion master controller by extending the phase count. Compatible master controllers include the LTC3884, LTC3866, LTC3877 and LTC3774. The LTC3874 employs a unique architecture that enhances the signal-to-noise ratio of the current sense signal, allowing the use of sub-milliohm DC resistance power inductors to maximize efficiency while reducing switching jitter. Its peak current mode architecture allows for accurate phase to phase current sharing even for dynamic loads.

Effectively working with a master controller, the LTC3874 supports all the programmable features as well as fault protection.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

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

Part Number Package Code Temp Package
Drawing
RoHS
LTC3874EUFD#PBF 4x5 QFN-28 UFD E 05-08-1712 Yes
LTC3874EUFD#TRPBF 4x5 QFN-28 UFD E 05-08-1712 Yes
LTC3874IUFD#PBF 4x5 QFN-28 UFD I 05-08-1712 Yes
LTC3874IUFD#TRPBF 4x5 QFN-28 UFD I 05-08-1712 Yes


LTC3874 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC3874EUFD#PBF 4x5 QFN-28 E $3.53 $2.47 Yes
LTC3874EUFD#TRPBF 4x5 QFN-28 E $2.53 Yes
LTC3874IUFD#PBF 4x5 QFN-28 I $3.79 $2.65 Yes
LTC3874IUFD#TRPBF 4x5 QFN-28 I $2.71 Yes
Buy NowRequest Samples
* 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
DC2084A LTC3884EUK/LTC3874EUFD Demo Board | PolyPhase Digital PSM Buck with Sub-mΩ DCR Sensing Plus Two Slave Controllers, 10V ≤ VIN ≤ 14V, Vout = 0.5V to 1.5V @ 240A Contact Factory
DC2142A LTC3875EUJ/LTC3874IUFD Demo Board | 4.5V ≤ VIN ≤ 14V; VOUT: 1V @ 120A $225.00
DC2229A-B LTC3877/LTC3874 Demo Board | 4-Phase Buck Controller with VID Inputs, Sub-mΩ DCR sensing, 6V ≤ VIN ≤ 14V, Vout = 0.6V to 1.23V at 120A Contact Factory
Buy Now
Click here to view our complete list of demo boards

Designed for Automotive and Transportation Applications

AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC3874IUFD#PBF 4x5 QFN-28 I $3.79 $2.65 Yes
LTC3874IUFD#TRPBF 4x5 QFN-28 I $2.71 Yes
Buy NowRequest Samples
* 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.

Applications

  • High Current Distributed Power Systems
  • Telecom, Datacom, and Storage Systems
  • Intelligent Energy Efficient Power Regulation

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

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LTC3874

LTpowerCAD

The LTpowerCAD design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD

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Technical Support