LT3971

PRODUCTION

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

Part Models: 28
1ku List Price: Starting From $3.31

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Part Details

Ultralow Quiescent Current: 2.8μA I_Q Regulating 12V_IN to 3.3V_OUT
Fixed Output Voltages: 3.3V, 5V, 2.1μA I_Q Regulating 12V_IN to 3.3V_OUT
Low Ripple Burst Mode^® Operation: Output Ripple < 15mV_P-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: I_Q = 700nA
Power Good Flag
Soft-Start Capability
Internal Compensation
Output Voltage: 1.19V to 30V
Small Thermally Enhanced 10-Lead MSOP, 16-Lead MSOP and (3mm × 3mm) DFN Packages

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 V_OUT reaches 91% of the programmed output voltage. The LT3971 is available in small 10-lead MSOP and 3mm × 3mm DFN packages with exposed pads for low thermal resistance. A 16-lead MSOP is also offered which has enhanced pin-to-pin fault tolerance.


	Vout	Iout	Vref Accuracy
LT3971	Adj	1.2A	2.5%
LT3971-3.3	3.3V	1.2A	2.5%
LT3971-5	5V	1.2A	2.5%
LT3971A	Adj	1.3A	1.5%
LT3971A-5	5V	1.3A	1.5%

Applications

Automotive Battery Regulation
Power for Portable Products
Industrial Supplies

Part Models: 28
1ku List Price: Starting From $3.31

Documentation

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
LT3971EDD#PBF	10-Lead DFN (3mm x 3mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EDD#TRPBF	10-Lead DFN (3mm x 3mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EDD-3.3#PBF	10-Lead DFN (3mm x 3mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EDD-3.3#TRPBF	10-Lead DFN (3mm x 3mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EDD-5#PBF	10-Lead DFN (3mm x 3mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EDD-5#TRPBF	10-Lead DFN (3mm x 3mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EMSE#PBF	10-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EMSE#TRPBF	10-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EMSE-3.3#PBF	10-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EMSE-3.3#TRPBF	10-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EMSE-5#PBF	10-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EMSE-5#TRPBF	10-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EMSE16#PBF	16-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971EMSE16#TRPBF	16-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IDD#PBF	10-Lead DFN (3mm x 3mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IDD#TRPBF	10-Lead DFN (3mm x 3mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IDD-3.3#PBF	10-Lead DFN (3mm x 3mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IDD-3.3#TRPBF	10-Lead DFN (3mm x 3mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IDD-5#PBF	10-Lead DFN (3mm x 3mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IDD-5#TRPBF	10-Lead DFN (3mm x 3mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IMSE#PBF	10-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IMSE#TRPBF	10-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IMSE-3.3#PBF	10-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IMSE-3.3#TRPBF	10-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IMSE-5#PBF	10-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IMSE-5#TRPBF	10-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IMSE16#PBF	16-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LT3971IMSE16#TRPBF	16-Lead MSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN
No Match Found
Jun 5, 2024 - 24_0003 Epoxy Change from Henkel 8290 to 8290A for MSOP Package (2)
		PCN24_0003_Form Material_Report Qualification Results Summary Delta Qualification Matrix
LT3971EMSE#PBF	PRODUCTION
LT3971EMSE#TRPBF	PRODUCTION
LT3971EMSE-3.3#PBF	PRODUCTION
LT3971EMSE-3.3#TRPBF	PRODUCTION
LT3971EMSE-5#PBF	PRODUCTION
LT3971EMSE-5#TRPBF	PRODUCTION
LT3971IMSE-3.3#PBF	PRODUCTION
LT3971IMSE-3.3#TRPBF	PRODUCTION
LT3971IMSE-5#PBF	PRODUCTION
LT3971IMSE-5#TRPBF	PRODUCTION
Feb 4, 2020 - 20_0130 Laser Top Mark Conversion for 10-Lead MSOP Packages Assembled in ADPG and UTAC
		PCN20_0130_Form Material_Report
LT3971EMSE#PBF	PRODUCTION
LT3971EMSE#TRPBF	PRODUCTION
LT3971EMSE-3.3#PBF	PRODUCTION
LT3971EMSE-3.3#TRPBF	PRODUCTION
LT3971EMSE-5#PBF	PRODUCTION
LT3971EMSE-5#TRPBF	PRODUCTION
LT3971IMSE#PBF	PRODUCTION
LT3971IMSE#TRPBF	PRODUCTION
LT3971IMSE-3.3#PBF	PRODUCTION
LT3971IMSE-3.3#TRPBF	PRODUCTION
LT3971IMSE-5#PBF	PRODUCTION
LT3971IMSE-5#TRPBF	PRODUCTION
Oct 11, 2022 - 22_0244 Epoxy Change from Henkel 8290 to 8290A for MSOP Package
		PCN22_0244_Form Material_Report Qualification Results Summary Delta Qualification Matrix
LT3971EMSE16#PBF
LT3971EMSE16#TRPBF
LT3971IMSE#PBF	PRODUCTION
LT3971IMSE#TRPBF	PRODUCTION
LT3971IMSE16#PBF
LT3971IMSE16#TRPBF
Feb 4, 2020 - 20_0132 Laser Top Mark for 16-Lead MSOP Packages Assembled in ADPG and UTAC
		PCN20_0132_Form Material_Report
LT3971EMSE16#PBF
LT3971EMSE16#TRPBF
LT3971IMSE16#PBF
LT3971IMSE16#TRPBF
Jul 12, 2022 - 22_0157 UTAC Thai Limited (UTL) as Alternate Assembly Site for MSOP Packages [With Modification in BOM]
		PCN22_0157_Form Material_Report Qualification Results Summary Delta Qualification Matrix Detailed Parts List
LT3971IMSE#PBF	PRODUCTION
LT3971IMSE#TRPBF	PRODUCTION
LT3971IMSE-5#PBF	PRODUCTION
LT3971IMSE-5#TRPBF	PRODUCTION
Jun 21, 2022 - 22_0050 UTAC Thai Limited (UTL) as Alternate Assembly Site for MSOP Packages / Devices
		PCN22_0050_Form Material_Report Qualification Results Summary Delta Qualification Matrix
LT3971IMSE#PBF	PRODUCTION
LT3971IMSE#TRPBF	PRODUCTION
LT3971IMSE-5#PBF	PRODUCTION
LT3971IMSE-5#TRPBF	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Hardware Ecosystem

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Tools & Simulations

LTspice 2

Models for the following parts are available in LTspice:

LT3971
LT3971-3.3
LT3971-5
LT3971A
LT3971A-5

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

Evaluation Kits

LT3971EMSE Demo Board | 4.5V ≤ VIN ≤ 38V, VOUT = 3.3V @ 1.2A

Buy Now View Details

Product Details

Demonstration circuit 1527 is a monolithic step-down DC/DC switching regulator featuring the LT3971. The switching frequency is adjustable up to 2MHz. The demo circuit is designed for 3.3V, 1.2A output from a 4.5V to 38V input. The circuit consumes only 2.8μA of quiescent current.

Resources

DC1527A - Demo Manual
595.00K

DC1527A - Design Files
638.00K

DC1527A - Schematic
37.00K

Latest Discussions

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LT3971

Part Details

Documentation

Data Sheet 1

Reliability Data 1

User Guide 1

Technical Articles 1

Video 1