Features and Benefits
- 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
The LTC3874 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.
- High Current Distributed Power Systems
- Telecom, Datacom, and Storage Systems
- Intelligent Energy Efficient Power Regulation
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (3)
Demonstration circuit 2084A is a high efficiency, high density, single-output step-down solution featuring the LTC3884 and two LTC3874's. The LTC3884 is a dual output PolyPhase® step-down controller with ultralow DCR sensing and digital power system management. The LTC3874 is a PolyPhase step-down synchronous slave controller also with sub-milliohm DCR Sensing. The combination provides a circuit with a 10V to 14V input voltage range that can supply up to 240A of output current. The default output voltage is 1V, but can be set from 0.5V to 1.5V.
The DC2084A powers up to default settings and produces power based on configuration resistors or with its non-volatile memory without the need for any serial bus communication. This allows easy evaluation of the DC/DC converter. To fully explore the extensive power system management features of the part, download the GUI software LTpowerPlay® and use LTC’s I2C/SMBus/PMBus dongle DC1613A to connect to the board.
Demonstration circuits 2229A-A and 2229A-B feature the LTC3877 in two high output current, high efficiency, VID programmed step-down converters with sub-mΩ DCR sensing. For both converters, the input voltage range is 6V to 14V and the switching frequency is 400kHz.
Demonstration circuit 2142A is a high efficiency, high density, 4-phase synchronous buck converter with a 4.5V to 14V input range. It can supply 120A maximum load current at a 1.0V output. This demo board incorporates the LTC3875EUJ and LTC3874IUFD master/slave controllers.
Tools & Simulations
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.
Models for the following parts are available in LTspice:
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.
LTC3874 Companion Parts
Recommended Related Parts
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.
Sample & Buy
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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.