LTC3646/LTC3646-1 - 40V, 1A Synchronous Step-Down Converter

Features

  • Wide Input Voltage Range: 4.0V to 40V
  • 1A Guaranteed Output Current
  • High Efficiency: Up to 95%
  • Wide Output Voltage Range
    LTC3646: 2.0V to 30V
    LTC3646-1: 0.6V to 15V
  • ±1% Accurate Reference Voltage
  • Internal or External Compensation
  • Switching Frequency Adjustable and Synchronizable: 200kHz to 3MHz
  • Selectable High Efficiency Burst Mode® Operation or Forced Continuous Mode
  • 14 Lead 3mm × 4mm DFN or Thermally Enhanced
  • 16-Lead MSOP Packages
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LTC3646 Typical Application
LTC3646 Typical Application

Description

The LTC®3646 is a high efficiency, step-down DC/DC converter with internal high side and synchronous power FETs. It draws only 140μA typical DC supply current in Burst Mode operation at no load while maintaining output voltage regulation.

The LTC3646 can supply up to a 1A load, and its combination of Burst Mode operation, integrated power switches and low quiescent current provides high efficiency over a broad range of load currents. Alternatively, it can be used in forced continuous mode for ripple sensitive applications.

The LTC3646 has a wide 4.0V to 40V input range and its patented controlled on-time architecture and 0.6V reference voltage allow for large step-down ratios without the risk of output overvoltage. The frequency may be set between 200kHz and 3.0MHz with a program resistor or synchronized to an external clock.

The internal soft-start, short-circuit protection and voltage rating make the LTC3646 a robust part ideal for high voltage applications.

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
LTC3646EDE-1#PBF 4x3 DFN-14 DE E 05-08-1708 Yes
LTC3646EDE-1#TRPBF 4x3 DFN-14 DE E 05-08-1708 Yes
LTC3646EDE#PBF 4x3 DFN-14 DE E 05-08-1708 Yes
LTC3646EDE#TRPBF 4x3 DFN-14 DE E 05-08-1708 Yes
LTC3646EMSE-1#PBF MS-16E MSE E 05-08-1667 Yes
LTC3646EMSE-1#TRPBF MS-16E MSE E 05-08-1667 Yes
LTC3646EMSE#PBF MS-16E MSE E 05-08-1667 Yes
LTC3646EMSE#TRPBF MS-16E MSE E 05-08-1667 Yes
LTC3646HDE-1#PBF 4x3 DFN-14 DE H 05-08-1708 Yes
LTC3646HDE-1#TRPBF 4x3 DFN-14 DE H 05-08-1708 Yes
LTC3646HDE#PBF 4x3 DFN-14 DE H 05-08-1708 Yes
LTC3646HDE#TRPBF 4x3 DFN-14 DE H 05-08-1708 Yes
LTC3646HMSE-1#PBF MS-16E MSE H 05-08-1667 Yes
LTC3646HMSE-1#TRPBF MS-16E MSE H 05-08-1667 Yes
LTC3646HMSE#PBF MS-16E MSE H 05-08-1667 Yes
LTC3646HMSE#TRPBF MS-16E MSE H 05-08-1667 Yes
LTC3646IDE-1#PBF 4x3 DFN-14 DE I 05-08-1708 Yes
LTC3646IDE-1#TRPBF 4x3 DFN-14 DE I 05-08-1708 Yes
LTC3646IDE#PBF 4x3 DFN-14 DE I 05-08-1708 Yes
LTC3646IDE#TRPBF 4x3 DFN-14 DE I 05-08-1708 Yes
LTC3646IMSE-1#PBF MS-16E MSE I 05-08-1667 Yes
LTC3646IMSE-1#TRPBF MS-16E MSE I 05-08-1667 Yes
LTC3646IMSE#PBF MS-16E MSE I 05-08-1667 Yes
LTC3646IMSE#TRPBF MS-16E MSE I 05-08-1667 Yes


LTC3646 Package Drawing
LTC3646 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
LTC3646EDE-1#PBF 4x3 DFN-14 E $4.07 $2.85 Yes
LTC3646EDE-1#TRPBF 4x3 DFN-14 E $2.91 Yes
LTC3646EDE#PBF 4x3 DFN-14 E $4.07 $2.85 Yes
LTC3646EDE#TRPBF 4x3 DFN-14 E $2.91 Yes
LTC3646EMSE-1#PBF MS-16E E $4.07 $2.85 Yes
LTC3646EMSE-1#TRPBF MS-16E E $2.91 Yes
LTC3646EMSE#PBF MS-16E E $4.07 $2.85 Yes
LTC3646EMSE#TRPBF MS-16E E $2.91 Yes
LTC3646HDE-1#PBF 4x3 DFN-14 H $4.84 $3.39 Yes
LTC3646HDE-1#TRPBF 4x3 DFN-14 H $3.45 Yes
LTC3646HDE#PBF 4x3 DFN-14 H $4.84 $3.39 Yes
LTC3646HDE#TRPBF 4x3 DFN-14 H $3.45 Yes
LTC3646HMSE-1#PBF MS-16E H $4.84 $3.39 Yes
LTC3646HMSE-1#TRPBF MS-16E H $3.45 Yes
LTC3646HMSE#PBF MS-16E H $4.84 $3.39 Yes
LTC3646HMSE#TRPBF MS-16E H $3.45 Yes
LTC3646IDE-1#PBF 4x3 DFN-14 I $4.49 $3.14 Yes
LTC3646IDE-1#TRPBF 4x3 DFN-14 I $3.20 Yes
LTC3646IDE#PBF 4x3 DFN-14 I $4.49 $3.14 Yes
LTC3646IDE#TRPBF 4x3 DFN-14 I $3.20 Yes
LTC3646IMSE-1#PBF MS-16E I $4.49 $3.14 Yes
LTC3646IMSE-1#TRPBF MS-16E I $3.20 Yes
LTC3646IMSE#PBF MS-16E I $4.49 $3.14 Yes
LTC3646IMSE#TRPBF MS-16E I $3.20 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
DC1731A-A LTC3646 Demo Board (DFN) I 4V ≤ VIN ≤ 40V, Vout = 3.3V or 5V @ 1A $150.00
DC1731A-B LTC3646-1 Demo Board (DFN) | 4V ≤ VIN ≤ 40V, Vout = 3.3V or 5V @ 1A $150.00
DC1820A-A LTC3646 Demo Board (MSOP) | 4V ≤ VIN ≤ 40V, Vout = 3.3V or 5V @ 1A $150.00
DC1820A-B LTC3646-1 Demo Board (MSOP) | 4V ≤ VIN ≤ 40V, Vout = 3.3V or 5V @ 1A 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
LTC3646HDE-1#PBF 4x3 DFN-14 H $4.84 $3.39 Yes
LTC3646HDE-1#TRPBF 4x3 DFN-14 H $3.45 Yes
LTC3646HDE#PBF 4x3 DFN-14 H $4.84 $3.39 Yes
LTC3646HDE#TRPBF 4x3 DFN-14 H $3.45 Yes
LTC3646IDE-1#PBF 4x3 DFN-14 I $4.49 $3.14 Yes
LTC3646IDE-1#TRPBF 4x3 DFN-14 I $3.20 Yes
LTC3646IDE#PBF 4x3 DFN-14 I $4.49 $3.14 Yes
LTC3646IDE#TRPBF 4x3 DFN-14 I $3.20 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

  • Point of Load Power Supply
  • Intermediate Bus Power
  • Automotive Applications

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:

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice IV:
LTC3646
LTC3646-1

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:

Design tools for the following parts are available in LTpowerCAD:
LTC3646
LTC3646-1

Technical Support