LTC3870 - PolyPhase Step-Down Slave Controller for Digital Power System Management
Features
- LTC3880 Family Phase Extender Supporting LTC3880/3880-1, LTC3883/3883-1, LTC3886, LTC3887 Master Controllers
- Cascade with Multiple Chips for Very Large Current Applications
- Accurate PolyPhase Current Sharing
- EXTVCC Capable of 5V to 14V Input
- Wide VIN Range: 4.5V to 60V
- Wide Output Voltage Range : 0.5V to 14V
- Wide SYNC Frequency Range: 100kHz to 1MHz
- Pin Programmable of CCM/DCM Operation
- Pin Programmable of Phase-Shift Control
- Integrated Powerful N-Channel MOSFET Gate Drivers
- Available in a 28-Pin (4mm × 5mm) QFN Package
Typical Application
Description
The LTC®3870 is a PolyPhase® step-down slave controller specially designed for multiphase operation with the LTC3880 family digital power system management DC/DC controllers. It provides a small and cost effective solution for supplying very large currents by cascading it with a master controller. A peak current mode architecture provides the LTC3870 with excellent current sharing from phase to phase and from chip to chip.
Coherently working with the LTC3880 family, the LTC3870 does not require additional I2C addresses, and it supports all programmable features as well as fault protection. The constant switching frequency can be synchronized to an external clock from the master controller from 100kHz to 1MHz.
| Onboard MOSFET Gate Drivers | Package | |
| LTC3870 | Yes | 4x5 QFN-28 |
| LTC3870-1 | No – Works with DrMOS and Power Blocks | 4x4 QFN-24 |
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 |
|---|---|---|---|---|---|
| LTC3870EUFD#PBF | 4x5 QFN-28 | UFD | E | 05-08-1712 | Yes |
| LTC3870EUFD#TRPBF | 4x5 QFN-28 | UFD | E | 05-08-1712 | Yes |
| LTC3870IUFD#PBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
| LTC3870IUFD#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 | |
|---|---|---|---|---|---|---|
| LTC3870EUFD#PBF | 4x5 QFN-28 | E | $3.36 | $2.35 | Yes | |
| LTC3870EUFD#TRPBF | 4x5 QFN-28 | E | $2.41 | Yes | ||
| LTC3870IUFD#PBF | 4x5 QFN-28 | I | $3.62 | $2.53 | Yes | |
| LTC3870IUFD#TRPBF | 4x5 QFN-28 | I | $2.59 | 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 |
|---|---|---|---|
| DC2089A-A | LTC3880EUJ/LTC3870EUFD RSENSE Demo Board | 7V ≤ VIN ≤ 14V; VOUT = 0.8V to 1.8V @ 80A | Contact Factory | |
| DC2089A-B | LTC3880EUJ/LTC3870EUFD DCR SENSE Demo Board | 7V ≤ VIN ≤ 14V; VOUT = 0.8V to 1.8V @ 80A | $275.00 | |
| DC2155A-B | LTC3886UKG/LTC3870UFD Demo Board (RSENSE) | 4 Phase Single Output PMBus Buck 18V≤VIN ≤54V, VOUT=12V at 48A, 150kHz | Contact Factory | |
| Buy Now | |||
Companion Boards
| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC1613A | USB-to-PMBus Controller for Use with LTpowerPlay | $50.00 | |
| Buy Now | |||
Applications
- High Power Distributed Power Systems
- Telecom Systems
- Industrial Applications
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Product Notifications
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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
Models for the following parts are available in LTspice:
LTC3870
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.
