LT3501 - Monolithic Dual Tracking 3A Step-Down Switching Regulator

Features

  • Wide Input Range: 3.1V to 25V
  • Two Switching Regulators with 3A Output Capability
  • Independent Supply to Each Regulator
  • Adjustable/Synchronizable Fixed Frequency Operation from 250kHz to 1.5MHz
  • Antiphase Switching
  • Outputs Can be Paralleled
  • Independent, Sequential, Ratiometric or Absolute Tracking Between Outputs
  • Independent Soft-Start and Power Good Pins
  • Enhanced Short-Circuit Protection
  • Low Dropout: 95% Maximum Duty Cycle
  • Low Shutdown Current: <10µA
  • 20-Lead TSSOP Package with Exposed Leadframe
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LT3501 Typical Application
LT3501 Typical Application

Description

The LT3501 is a dual current mode PWM step-down DC/DC converter with two internal 3.5A switches. Independent input voltage, feedback, soft-start and power good pins for each channel simplify complex power supply tracking/sequencing requirements.

Both converters are synchronized to either a common external clock input or a resistor programmable fi xed 250kHz to 1.5MHz internal oscillator. At all frequencies, a 180° phase relationship between channels is maintained, reducing voltage ripple and component size. Programmable frequency allows for optimization between effi ciency and external component size.

Minimum input-to-output voltage ratios are improved by allowing the switch to stay on through multiple clock cycles, only switching off when the boost capacitor needs recharging, resulting in ~95% maximum duty cycle.

Each output can be independently disabled using its own soft-start pin, or by using the SHDN pin the entire part can be placed in a low quiescent current shutdown mode.

The LT3501 is available in a 20-lead TSSOP package with exposed leadframe for low thermal resistance.

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
LT3501EFE#PBF TSSOP-20 FE E 05-08-1663 (CB) Yes
LT3501EFE#TRPBF TSSOP-20 FE E 05-08-1663 (CB) Yes
LT3501IFE#PBF TSSOP-20 FE I 05-08-1663 (CB) Yes
LT3501IFE#TRPBF TSSOP-20 FE I 05-08-1663 (CB) Yes


LT3501 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
LT3501EFE#PBF TSSOP-20 E $5.41 $3.50 Yes
LT3501EFE#TRPBF TSSOP-20 E $3.55 Yes
LT3501IFE#PBF TSSOP-20 I $6.48 $4.20 Yes
LT3501IFE#TRPBF TSSOP-20 I $4.25 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
DC964A LT3501EFE Demo Board | Dual, 4.5V ≤ VIN ≤ 24V, Vout1 = 3.3V @ 3A, Vout2 = 1.8V @ 3A $225.00
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
LT3501IFE#PBF TSSOP-20 I $6.48 $4.20 Yes
LT3501IFE#TRPBF TSSOP-20 I $4.25 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

  • DSP Power Supplies
  • Disc Drives
  • DSL/Cable Modems
  • Wall Transformer Regulation
  • Distributed Power Regulation

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

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:
LT3501

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

Design tools for the following parts are available in LTpowerCAD:
LT3501

Technical Support