LTC3865/LTC3865-1 - Dual, 2-Phase Synchronous DC/DC Controller with Pin Selectable Outputs

Features

  • Dual, 180° Phased Controllers
  • 2-Pin VID Output Voltage Programming from 0.6V to 5V
  • High Efficiency: Up to 95%
  • RSENSE or DCR Current Sensing
  • Phase-Lockable Fixed Frequency 250kHz to 770kHz
  • Adjustable Current Limit
  • Dual N-Channel MOSFET Synchronous Drive
  • Wide VIN Range: 4.5V to 38V Operation
  • Adjustable Soft-Start Current Ramping or Tracking
  • Output OV Protection With Reverse Current Limit
  • Power Good Output Voltage Monitor
  • 32-Pin 5mm × 5mm QFN and 38-Lead TSSOP Packages
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LTC3865 Typical Application
LTC3865 Typical Application

Description

The LTC3865/LTC3865-1 are high performance dual synchronous step-down DC/DC switching regulator controllers that drive all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows a phase-lockable frequency of up to 770kHz. Power loss and noise are minimized by operating the two controller output stages out of phase.

OPTI-LOOP® compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. Independent track/soft-start pins for each controller ramp the output voltage during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The MODE/PLLIN pin selects among Burst Mode® operation, pulse-skipping mode, and continuous inductor current mode. The output voltages can be precisely programmed by pin strapping or external resistors.

The LTC3865/LTC3865-1 are available in low profile (5mm × 5mm) 32-pin QFN and 38-Lead thermally enhanced TSSOP packages.

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
LTC3865EFE#PBF TSSOP-38 FE E 05-08-1772 Yes
LTC3865EFE#TRPBF TSSOP-38 FE E 05-08-1772 Yes
LTC3865EUH-1#PBF 5x5 QFN-32 UH E 05-08-1693 Yes
LTC3865EUH-1#TRPBF 5x5 QFN-32 UH E 05-08-1693 Yes
LTC3865EUH#PBF 5x5 QFN-32 UH E 05-08-1693 Yes
LTC3865EUH#TRPBF 5x5 QFN-32 UH E 05-08-1693 Yes
LTC3865IFE#PBF TSSOP-38 FE I 05-08-1772 Yes
LTC3865IFE#TRPBF TSSOP-38 FE I 05-08-1772 Yes
LTC3865IUH-1#PBF 5x5 QFN-32 UH I 05-08-1693 Yes
LTC3865IUH-1#TRPBF 5x5 QFN-32 UH I 05-08-1693 Yes
LTC3865IUH#PBF 5x5 QFN-32 UH I 05-08-1693 Yes
LTC3865IUH#TRPBF 5x5 QFN-32 UH I 05-08-1693 Yes


LTC3865 Package Drawing
LTC3865 Package Drawing
LTC3865 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
LTC3865EFE#PBF TSSOP-38 E $4.08 $2.87 Yes
LTC3865EFE#TRPBF TSSOP-38 E $2.93 Yes
LTC3865EUH-1#PBF 5x5 QFN-32 E $3.79 $2.65 Yes
LTC3865EUH-1#TRPBF 5x5 QFN-32 E $2.71 Yes
LTC3865EUH#PBF 5x5 QFN-32 E $3.79 $2.65 Yes
LTC3865EUH#TRPBF 5x5 QFN-32 E $2.71 Yes
LTC3865IFE#PBF TSSOP-38 I $4.47 $3.14 Yes
LTC3865IFE#TRPBF TSSOP-38 I $3.20 Yes
LTC3865IUH-1#PBF 5x5 QFN-32 I $4.20 $2.94 Yes
LTC3865IUH-1#TRPBF 5x5 QFN-32 I $3.00 Yes
LTC3865IUH#PBF 5x5 QFN-32 I $4.20 $2.94 Yes
LTC3865IUH#TRPBF 5x5 QFN-32 I $3.00 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
DC1479A LTC3865EUH Demo Board | 4.5V ≤ VIN ≤ 14V, VOUT1 = 1.5V @ 15A, VOUT2 =1.2V @ 15A Contact Factory
DC1480A LTC3865EUH-1 Demo Board | 4.5V ≤ VIN ≤ 14V, VOUT1 = 3.3V @ 5A, VOUT2 =1.8V @ 5A 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
LTC3865IFE#PBF TSSOP-38 I $4.47 $3.14 Yes
LTC3865IFE#TRPBF TSSOP-38 I $3.20 Yes
LTC3865IUH-1#PBF 5x5 QFN-32 I $4.20 $2.94 Yes
LTC3865IUH-1#TRPBF 5x5 QFN-32 I $3.00 Yes
LTC3865IUH#PBF 5x5 QFN-32 I $4.20 $2.94 Yes
LTC3865IUH#TRPBF 5x5 QFN-32 I $3.00 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

  • DC Power Distribution Systems

Product Notifications

Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.

Forgot your password? Click here.
Need help? Email mylinear@linear.com with questions and comments.

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:
LTC3865
LTC3865-1

Technical Support