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
AEC-Q100 data available for specific packages
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 |
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 Now • Request Samples | ||||||
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 | |||
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 Now • Request Samples | ||||||
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
To launch a ready to run LTspice demonstration circuit for this part:
- Step 1: If you have not installed LTspice on this computer, download and install LTspice
- Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
- Step 3: If LTspice does not automatically open after clicking the link above, 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
To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.
Models for the following parts are available in LTspice:
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
To open the project file for this circuit:
- Step 1: If you have not installed LTpowerCAD on this computer, download and install LTpowerCAD
- Step 2: Once LTpowerCAD is installed, click on the link(s) below to open the project file
- Step 3: If LTpowerCAD does not automatically open after clicking the link above, you can open the project file by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTpowerCAD and open the project file by selecting 'Open Project' from the 'File' menu
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
