LT3970 Series - 40V, 350mA Step-Down Regulator with 2.5μA Quiescent Current and Integrated Diodes

Features

  • Low Ripple Burst Mode® Operation
    2.5μA IQ at 12VIN to 3.3VOUT
    Output Ripple < 5mVP-P
  • Wide Input Voltage Range: 4.2V to 40V Operating
  • Adjustable Switching Frequency: 200kHz to 2.2MHz
  • Integrated Boost and Catch Diodes
  • 350mA Output Current
  • Fixed Output Voltages: 3.3V, 3.42V, 5V
    1.8μA IQ at 12VIN
  • Accurate 1V Enable Pin Threshold
  • Low Shutdown Current: IQ = 0.7μA
  • Internal Sense Limits Catch Diode Current
  • Power Good Flag
  • Output Voltage: 1.21V to 25V
  • Internal Compensation
  • Small 10-Pin MSOP and (3mm × 2mm) DFN Packages
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LT3970 Typical Application
LT3970 Typical Application

Description

The LT®3970 is an adjustable frequency monolithic buck switching regulator that accepts a wide input voltage range up to 40V, and consumes only 2.5μA of quiescent current. A high efficiency switch is included on the die along with the catch diode, boost diode, and the necessary oscillator, control and logic circuitry. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping the output ripple below 5mV in a typical application. Current mode topology is used for fast transient response and good loop stability. A catch diode current limit provides protection against shorted outputs and overvoltage conditions. An enable pin with accurate threshold is available, producing a low shutdown current of 0.7μA. A power good flag signals when VOUT reaches 90% of the programmed output voltage. The LT3970 is available in small 10-pin MSOP and 3mm × 2mm DFN 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
LT3970EDDB-3.3#PBF 3x2 DFN-10 DDB E 05-08-1722 Yes
LT3970EDDB-3.3#TRMPBF 3x2 DFN-10 DDB E 05-08-1722 Yes
LT3970EDDB-3.3#TRPBF 3x2 DFN-10 DDB E 05-08-1722 Yes
LT3970EDDB-3.42#PBF 3x2 DFN-10 DDB E 05-08-1722 Yes
LT3970EDDB-3.42#TRMPBF 3x2 DFN-10 DDB E 05-08-1722 Yes
LT3970EDDB-3.42#TRPBF 3x2 DFN-10 DDB E 05-08-1722 Yes
LT3970EDDB-5#PBF 3x2 DFN-10 DDB E 05-08-1722 Yes
LT3970EDDB-5#TRMPBF 3x2 DFN-10 DDB E 05-08-1722 Yes
LT3970EDDB-5#TRPBF 3x2 DFN-10 DDB E 05-08-1722 Yes
LT3970EDDB#PBF 3x2 DFN-10 DDB E 05-08-1722 Yes
LT3970EDDB#TRMPBF 3x2 DFN-10 DDB E 05-08-1722 Yes
LT3970EDDB#TRPBF 3x2 DFN-10 DDB E 05-08-1722 Yes
LT3970EMS-3.3#PBF MS-10 MS E 05-08-1661 Yes
LT3970EMS-3.3#TRPBF MS-10 MS E 05-08-1661 Yes
LT3970EMS-5#PBF MS-10 MS E 05-08-1661 Yes
LT3970EMS-5#TRPBF MS-10 MS E 05-08-1661 Yes
LT3970EMS#PBF MS-10 MS E 05-08-1661 Yes
LT3970EMS#TRPBF MS-10 MS E 05-08-1661 Yes
LT3970HMS-3.3#PBF MS-10 MS H 05-08-1661 Yes
LT3970HMS-3.3#TRPBF MS-10 MS H 05-08-1661 Yes
LT3970HMS-5#PBF MS-10 MS H 05-08-1661 Yes
LT3970HMS-5#TRPBF MS-10 MS H 05-08-1661 Yes
LT3970HMS#PBF MS-10 MS H 05-08-1661 Yes
LT3970HMS#TRPBF MS-10 MS H 05-08-1661 Yes
LT3970IDDB-3.3#PBF 3x2 DFN-10 DDB I 05-08-1722 Yes
LT3970IDDB-3.3#TRMPBF 3x2 DFN-10 DDB I 05-08-1722 Yes
LT3970IDDB-3.3#TRPBF 3x2 DFN-10 DDB I 05-08-1722 Yes
LT3970IDDB-5#PBF 3x2 DFN-10 DDB I 05-08-1722 Yes
LT3970IDDB-5#TRMPBF 3x2 DFN-10 DDB I 05-08-1722 Yes
LT3970IDDB-5#TRPBF 3x2 DFN-10 DDB I 05-08-1722 Yes
LT3970IDDB#PBF 3x2 DFN-10 DDB I 05-08-1722 Yes
LT3970IDDB#TRMPBF 3x2 DFN-10 DDB I 05-08-1722 Yes
LT3970IDDB#TRPBF 3x2 DFN-10 DDB I 05-08-1722 Yes
LT3970IMS-3.3#PBF MS-10 MS I 05-08-1661 Yes
LT3970IMS-3.3#TRPBF MS-10 MS I 05-08-1661 Yes
LT3970IMS-5#PBF MS-10 MS I 05-08-1661 Yes
LT3970IMS-5#TRPBF MS-10 MS I 05-08-1661 Yes
LT3970IMS#PBF MS-10 MS I 05-08-1661 Yes
LT3970IMS#TRPBF MS-10 MS I 05-08-1661 Yes


LT3970 Package Drawing
LT3970 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
LT3970EDDB-3.3#PBF 3x2 DFN-10 E $3.36 Yes
LT3970EDDB-3.3#TRMPBF 3x2 DFN-10 E $3.36 $2.40 Yes
LT3970EDDB-3.3#TRPBF 3x2 DFN-10 E $3.36 $2.35 Yes
LT3970EDDB-3.42#PBF 3x2 DFN-10 E $3.36 Yes
LT3970EDDB-3.42#TRMPBF 3x2 DFN-10 E $3.36 $2.40 Yes
LT3970EDDB-3.42#TRPBF 3x2 DFN-10 E $3.36 $2.35 Yes
LT3970EDDB-5#PBF 3x2 DFN-10 E $3.36 Yes
LT3970EDDB-5#TRMPBF 3x2 DFN-10 E $3.36 $2.40 Yes
LT3970EDDB-5#TRPBF 3x2 DFN-10 E $3.36 $2.35 Yes
LT3970EDDB#PBF 3x2 DFN-10 E $3.36 Yes
LT3970EDDB#TRMPBF 3x2 DFN-10 E $3.36 $2.40 Yes
LT3970EDDB#TRPBF 3x2 DFN-10 E $3.36 $2.35 Yes
LT3970EMS-3.3#PBF MS-10 E $3.43 $2.40 Yes
LT3970EMS-3.3#TRPBF MS-10 E $2.46 Yes
LT3970EMS-5#PBF MS-10 E $3.43 $2.40 Yes
LT3970EMS-5#TRPBF MS-10 E $2.46 Yes
LT3970EMS#PBF MS-10 E $3.43 $2.40 Yes
LT3970EMS#TRPBF MS-10 E $3.78 $2.46 Yes
LT3970HMS-3.3#PBF MS-10 H $4.17 $2.92 Yes
LT3970HMS-3.3#TRPBF MS-10 H $2.98 Yes
LT3970HMS-5#PBF MS-10 H $4.17 $2.92 Yes
LT3970HMS-5#TRPBF MS-10 H $2.98 Yes
LT3970HMS#PBF MS-10 H $4.17 $2.92 Yes
LT3970HMS#TRPBF MS-10 H $2.98 Yes
LT3970IDDB-3.3#PBF 3x2 DFN-10 I $3.73 Yes
LT3970IDDB-3.3#TRMPBF 3x2 DFN-10 I $3.73 $2.66 Yes
LT3970IDDB-3.3#TRPBF 3x2 DFN-10 I $3.73 $2.61 Yes
LT3970IDDB-5#PBF 3x2 DFN-10 I $3.73 Yes
LT3970IDDB-5#TRMPBF 3x2 DFN-10 I $3.73 $2.66 Yes
LT3970IDDB-5#TRPBF 3x2 DFN-10 I $3.73 $2.61 Yes
LT3970IDDB#PBF 3x2 DFN-10 I $3.73 Yes
LT3970IDDB#TRMPBF 3x2 DFN-10 I $3.73 $2.66 Yes
LT3970IDDB#TRPBF 3x2 DFN-10 I $3.73 $2.61 Yes
LT3970IMS-3.3#PBF MS-10 I $3.82 $2.67 Yes
LT3970IMS-3.3#TRPBF MS-10 I $2.73 Yes
LT3970IMS-5#PBF MS-10 I $3.82 $2.67 Yes
LT3970IMS-5#TRPBF MS-10 I $2.73 Yes
LT3970IMS#PBF MS-10 I $3.82 $2.67 Yes
LT3970IMS#TRPBF MS-10 I $4.22 $2.73 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
DC1566A LT3970EMS Demo Board | 40V, 350mA Step-Down Regulator with 2uA Quiescent Current and Integrated Diodes $75.00
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
LT3970HMS-3.3#PBF MS-10 H $4.17 $2.92 Yes
LT3970HMS-3.3#TRPBF MS-10 H $2.98 Yes
LT3970HMS-5#PBF MS-10 H $4.17 $2.92 Yes
LT3970HMS-5#TRPBF MS-10 H $2.98 Yes
LT3970HMS#PBF MS-10 H $4.17 $2.92 Yes
LT3970HMS#TRPBF MS-10 H $2.98 Yes
LT3970IDDB-3.3#PBF 3x2 DFN-10 I $3.73 Yes
LT3970IDDB-3.3#TRMPBF 3x2 DFN-10 I $3.73 $2.66 Yes
LT3970IDDB-3.3#TRPBF 3x2 DFN-10 I $3.73 $2.61 Yes
LT3970IDDB-5#PBF 3x2 DFN-10 I $3.73 Yes
LT3970IDDB-5#TRMPBF 3x2 DFN-10 I $3.73 $2.66 Yes
LT3970IDDB-5#TRPBF 3x2 DFN-10 I $3.73 $2.61 Yes
LT3970IDDB#PBF 3x2 DFN-10 I $3.73 Yes
LT3970IDDB#TRMPBF 3x2 DFN-10 I $3.73 $2.66 Yes
LT3970IDDB#TRPBF 3x2 DFN-10 I $3.73 $2.61 Yes
LT3970IMS-3.3#PBF MS-10 I $3.82 $2.67 Yes
LT3970IMS-3.3#TRPBF MS-10 I $2.73 Yes
LT3970IMS-5#PBF MS-10 I $3.82 $2.67 Yes
LT3970IMS-5#TRPBF MS-10 I $2.73 Yes
LT3970IMS#PBF MS-10 I $3.82 $2.67 Yes
LT3970IMS#TRPBF MS-10 I $4.22 $2.73 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

  • Automotive Battery Regulation
  • Power for Portable Products
  • Industrial Supplies

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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:
LT3970
LT3970-3.3
LT3970-5

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:
LT3970

Technical Support