LT3975
42V, 2.5A, 2MHz Step-Down Switching Regulator with 2.7µA Quiescent Current
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Overview
Features and Benefits
- Ultralow Quiescent Current:
- 2.7μA IQ at 12VIN to 3.3VOUT
- Low Ripple Burst Mode® Operation
- Output Ripple < 15mVP-P
- Wide Input Range: Operation from 4.3V to 42V
- 2.5A Maximum Output Current
- Excellent Start-Up and Dropout Performance
- Adjustable Switching Frequency: 200kHz to 2MHz
- Synchronizable Between 250kHz to 2MHz
- Accurate Programmable Undervoltage Lockout
- Low Shutdown Current: IQ = 700nA
- Power Good Flag
- Soft-Start Capability
- Thermal Shutdown Protection
- Current Limit Foldback with Soft-Start Override
- Saturating Switch Design: 75mΩ On Resistance
- Small, Thermally Enhanced 16-Lead MSOP Package
Product Details
The LT3975 is an adjustable frequency monolithic buck switching regulator that accepts a wide input voltage range up to 42V. Low quiescent current design consumes only 2.7μA 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. The LT3975 can supply up to 2.5A of load current and has current limit foldback to limit power dissipation during short circuit. A low dropout voltage of 500mV is maintained when the input voltage drops below the programmed output voltage, such as during automotive cold crank.
An internally compensated current mode topology is used for fast transient response and good loop stability. A high efficiency 75mΩ switch is included on the die along with a boost Schottky diode and the necessary oscillator, control, and logic circuitry. An accurate 1.02V threshold enable pin can be driven directly from a microcontroller or used as a programmable undervoltage lockout. A capacitor on the SS pin provides a controlled inrush current (soft-start). A power good flag signals when VOUT reaches 91.6% of the programmed output voltage. The LT3975 is available in a small 16-lead MSOP package with exposed pad for low thermal resistance.
Applications
- Automotive Battery Regulation
- Portable Products
- Industrial Supplies
Product Categories
Markets and Technologies
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.
Evaluation Kits (1)
Documentation & Resources
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R530 Reliability Data3/26/2018
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DC1736A - Demo Manual7/26/2012
Tools & Simulations
LTspice
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LTspice Simulations
Models for the following parts are available in LTspice:
LT3975
Product Recommendations
LT3975 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 |
|---|---|---|---|---|
| LT3975EMSE#PBF | Material Declaration | Reliability Data | 16-Lead MSOP w/ EP | |
| LT3975EMSE#TRPBF | Material Declaration | Reliability Data | 16-Lead MSOP w/ EP | |
| LT3975HMSE#PBF | Material Declaration | Reliability Data | 16-Lead MSOP w/ EP | |
| LT3975HMSE#TRPBF | Material Declaration | Reliability Data | 16-Lead MSOP w/ EP | |
| LT3975IMSE#PBF | Material Declaration | Reliability Data | 16-Lead MSOP w/ EP | |
| LT3975IMSE#TRPBF | Material Declaration | Reliability Data | 16-Lead MSOP w/ EP | |
| Wafer Fabrication Data | R530 Reliability Data |
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Evaluation Boards
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.