LT3570 - 1.5A Buck Converter, 1.5A Boost Converter and LDO Controller

Features

  • 2.5V to 36V Input Voltage Range
  • Programmable Switching Frequency
  • from 500kHz to 2.1MHz
  • Synchronizable Up to 2.75MHz
  • VOUT(MIN): 0.8V
  • Independent Soft-Start for Each Converter
  • Separate VIN Supplies for Each Converter
  • Duty Cycle Range: 0% to 90% at 1MHz
  • Available in 24-Lead (4mm × 4mm) QFN and
  • 20-Lead TSSOP Packages
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LT3570 Typical Application
LT3570 Typical Application

Description

The LT3570 is a buck and boost converter with internal power switches and LDO controller. Each converter is designed with a 1.5A current limit and an input range from 2.5V to 36V, making the LT3570 ideal for a wide variety of applications. Switching frequencies up to 2.1MHz are programmed with an external timing resistor and the oscillator can be synchronized to an external clock up to 2.75MHz.

The LT3570 features a programmable soft-start function that limits the feedback voltage during start-up helping prevent overshoot and limiting inrush current. The LDO controller is capable of delivering up to 10mA of base current to an external NPN transistor.

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
LT3570EFE#PBF TSSOP-20 FE E 05-08-1663 (CB) Yes
LT3570EFE#TRPBF TSSOP-20 FE E 05-08-1663 (CB) Yes
LT3570EUF#PBF 4x4 QFN-24 UF E 05-08-1697 Yes
LT3570EUF#TRPBF 4x4 QFN-24 UF E 05-08-1697 Yes
LT3570IFE#PBF TSSOP-20 FE I 05-08-1663 (CB) Yes
LT3570IFE#TRPBF TSSOP-20 FE I 05-08-1663 (CB) Yes
LT3570IUF#3ZZPBF-ES I Yes
LT3570IUF#PBF 4x4 QFN-24 UF I 05-08-1697 Yes
LT3570IUF#TRPBF 4x4 QFN-24 UF I 05-08-1697 Yes


LT3570 Package Drawing
LT3570 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
LT3570EFE#PBF TSSOP-20 E $4.36 $3.05 Yes
LT3570EFE#TRPBF TSSOP-20 E $3.11 Yes
LT3570EUF#PBF 4x4 QFN-24 E $4.22 $2.95 Yes
LT3570EUF#TRPBF 4x4 QFN-24 E $3.01 Yes
LT3570IFE#PBF TSSOP-20 I $5.02 $3.51 Yes
LT3570IFE#TRPBF TSSOP-20 I $3.57 Yes
LT3570IUF#3ZZPBF-ES I Yes
LT3570IUF#PBF 4x4 QFN-24 I $4.84 $3.39 Yes
LT3570IUF#TRPBF 4x4 QFN-24 I $3.45 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
DC1106A LT3570EUF Demo Board | Buck + Boost + LDO Controller, 4V to 36Vin Buck with Vout1 = 3.3V@1A, 3.3V to 10Vin Boost with Vout2 = 12V@275mA, 100mA LDO $150.00
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
LT3570IFE#PBF TSSOP-20 I $5.02 $3.51 Yes
LT3570IFE#TRPBF TSSOP-20 I $3.57 Yes
LT3570IUF#PBF 4x4 QFN-24 I $4.84 $3.39 Yes
LT3570IUF#TRPBF 4x4 QFN-24 I $3.45 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

  • Cable and Satellite Set-Top Boxes
  • Automotive Systems
  • Telecom Systems
  • “Dying Gasp” Systems
  • TFT LCD Displays

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

Models for the following parts are available in LTspice:
LT3570

Technical Support