LT3971A
LT3971A-5
38V, 1.3A, 2MHz Step-Down Regulator with 2.2μA Quiescent Current
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Overview
Features and Benefits
- Ultralow Quiescent Current: 2.8μA IQ Regulating 12VIN to 3.3VOUT
- Fixed Output Voltages: 5V 2.2μA IQ Regulating 12VIN to 5VOUT
- Low Ripple Burst Mode® Operation: Output Ripple < 15mVP-P
- Wide Input Voltage Range: 4.3V to 38V
- 1.3A 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-Lead MSOP Package
Product Details
The LT3971A 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 LT3971A, 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 LT3971A is available in a small 10-lead MSOP package with an exposed pad for low thermal resistance.
The LT3971A and LT3971A-5 have a more accurate reference voltage compared to the LT3971 and LT3971-5. The LT3971A-5 also has specified VOUT pin current and ABSMAX current. These characteristics are important for USB applications.
| 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
- USB VBUS Regulation
- Automotive Battery Regulation
- Power for Portable Products
- Industrial Supplies
Product Lifecycle
Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Documentation & Resources
-
R530 Reliability Data3/26/2018
Tools & Simulations
LTspice
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.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, 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.
LTspice Simulations
Models for the following parts are available in LTspice:
LT3971
LT3971-3.3
LT3971-5
LT3971A
LT3971A-5
Product Recommendations
LT3971A Companion Parts
Design Resources
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 Number | Material Declaration | Reliability Data | Pin/Package Drawing | CAD Symbols, Footprints & 3D Models |
|---|---|---|---|---|
| LT3971AIMSE#PBF | Material Declaration | Reliability Data | 10-Lead MSOP w/ EP | |
| LT3971AIMSE#TRPBF | Material Declaration | Reliability Data | 10-Lead MSOP w/ EP | |
| LT3971AIMSE-5#PBF | Material Declaration | Reliability Data | 10-Lead MSOP w/ EP | |
| LT3971AIMSE-5#TRPBF | Material Declaration | Reliability Data | 10-Lead MSOP w/ EP | |
| Wafer Fabrication Data | R530 Reliability Data |
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Support & Discussions
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Buy Now Pricing
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List Pricing
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Lead Times
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