Power Management Switching Regulator Step-Down (Buck) Regulators Micropower Buck
Power Management Switching Regulator Step-Down (Buck) Regulators Internal Power Switch Buck
Power Management Switching Regulator Step-Down (Buck) Regulators High Input Voltage Buck

LT3971 - 38V, 1.2A, 2MHz Step-Down Regulator with 2.8μA Quiescent Current

Features

  • Ultralow Quiescent Current:
    2.8μA IQ Regulating 12VIN to 3.3VOUT
  • Fixed Output Voltages:
    3.3V, 5V, 2.1μA IQ Regulating 12VIN to 3.3VOUT
  • Low Ripple Burst Mode® Operation:
    Output Ripple < 15mVP-P
  • Wide Input Voltage Range: 4.3V to 38V
  • 1.2A Maximum Output Current
  • Adjustable Switching Frequency: 200kHz to 2MHz
  • Synchronizable Between 250kHz to 2MHz
  • Fast Transient Response
  • Accurate 1V Enable Pin Threshold
  • Low Shutdown Current: IQ = 700nA
  • Power Good Flag
  • Soft-Start Capability
  • Internal Compensation
  • Output Voltage: 1.19V to 30V
  • Small Thermally Enhanced 10-Pin MSOP Package and (3mm × 3mm) DFN Packages

Typical Application

LT3971 Typical Application
LT3971 Typical Application

Description

The LT3971 is an adjustable frequency monolithic buck switching regulator that accepts a wide input voltage range up to 38V. Low quiescent current design consumes only 2.8μA of supply current while regulating with no load. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping the output ripple below 15mV in a typical application. An internally compensated current mode topology is used for fast transient response and good loop stability. A high efficiency 0.33Ω switch is included on the die along with a boost Schottky diode and the necessary oscillator, control and logic circuitry. An accurate 1V threshold enable pin can be used to shut down the LT3971, reducing the input supply current to 700nA. A capacitor on the SS pin provides a controlled inrush current (soft-start). A power good flag signals when VOUT reaches 91% of the programmed output voltage. The LT3971 is available in small 10-pin MSOP and 3mm × 3mm DFN packages with exposed pads for low thermal resistance.

Packaging

For complete and up to date package information and drawings, please refer to our packaging page

MS-10, DFN-10

LT3971 Package Drawing
LT3971 Package Drawing
LT3971 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LT3971AIMSE#PBF MSOP 10 I $4.79 $3.35 View
LT3971AIMSE#TRPBF MSOP 10 I $3.41 View
LT3971AIMSE-5#PBF MSOP 10 I $4.79 $3.35 View
LT3971AIMSE-5#TRPBF MSOP 10 I $3.41 View
LT3971EDD#PBF DFN 10 E $3.93 $2.75 View
LT3971EDD#TRPBF DFN 10 E $2.81 View
LT3971EDD-3.3#PBF DFN 10 E $3.93 $2.75 View
LT3971EDD-3.3#TRPBF DFN 10 E $2.81 View
LT3971EDD-5#PBF DFN 10 E $3.93 $2.75 View
LT3971EDD-5#TRPBF DFN 10 E $2.81 View
LT3971EMSE#PBF MSOP 10 E $3.93 $2.75 View
LT3971EMSE#TRPBF MSOP 10 E $2.81 View
LT3971EMSE-3.3#PBF MSOP 10 E $3.93 $2.75 View
LT3971EMSE-3.3#TRPBF MSOP 10 E $2.81 View
LT3971EMSE-5#PBF MSOP 10 E $3.93 $2.75 View
LT3971EMSE-5#TRPBF MSOP 10 E $2.81 View
LT3971IDD#PBF DFN 10 I $4.37 $3.06 View
LT3971IDD#TRPBF DFN 10 I $3.12 View
LT3971IDD-3.3#PBF DFN 10 I $4.37 $3.06 View
LT3971IDD-3.3#TRPBF DFN 10 I $3.12 View
LT3971IDD-5#PBF DFN 10 I $4.37 $3.06 View
LT3971IDD-5#TRPBF DFN 10 I $3.12 View
LT3971IMSE#PBF MSOP 10 I $4.37 $3.06 View
LT3971IMSE#TRPBF MSOP 10 I $3.12 View
LT3971IMSE-3.3#PBF MSOP 10 I $4.37 $3.06 View
LT3971IMSE-3.3#TRPBF MSOP 10 I $3.12 View
LT3971IMSE-5#PBF MSOP 10 I $4.37 $3.06 View
LT3971IMSE-5#TRPBF MSOP 10 I $3.12 View
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* 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 demo boards are offered free of charge to qualified customers. Contact your local sales office or distributor to request 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
DC1527A LT3971EMSE Demo Board | 38V, 1.2A, 2MHz Step-Down Switching Regulator wi $100.00
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Click here to view our complete list of demo boards

Applications

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

Simulate

LTspice IV is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. To download LTspice IV and other FREE simulation tools, please visit our Design Simulation page.

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 IV
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice IV 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.

Related models available in LTspice IV
LT3971

Technical Support