LT3975
PRODUCTION42V, 2.5A, 2MHz Step-Down Switching Regulator with 2.7µA Quiescent Current
- Part Models
- 6
- 1ku List Price
- Starting From $4.71
Overview
- 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
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
Documentation
Data Sheet 1
User Guide 1
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 |
|---|---|---|---|
| LT3975EMSE#PBF | 16-Lead MSOP w/ EP | ||
| LT3975EMSE#TRPBF | 16-Lead MSOP w/ EP | ||
| LT3975HMSE#PBF | 16-Lead MSOP w/ EP | ||
| LT3975HMSE#TRPBF | 16-Lead MSOP w/ EP | ||
| LT3975IMSE#PBF | 16-Lead MSOP w/ EP | ||
| LT3975IMSE#TRPBF | 16-Lead MSOP w/ EP |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
Apr 17, 2025 - 25_0119 Bond Wire Change from Gold to Copper (Automotive) |
||
| LT3975EMSE#PBF | PRODUCTION | |
| LT3975EMSE#TRPBF | PRODUCTION | |
| LT3975IMSE#PBF | PRODUCTION | |
| LT3975IMSE#TRPBF | PRODUCTION | |
|
Oct 11, 2022 - 22_0244 Epoxy Change from Henkel 8290 to 8290A for MSOP Package |
||
| LT3975EMSE#PBF | PRODUCTION | |
| LT3975EMSE#TRPBF | PRODUCTION | |
| LT3975HMSE#PBF | PRODUCTION | |
| LT3975HMSE#TRPBF | PRODUCTION | |
| LT3975IMSE#PBF | PRODUCTION | |
| LT3975IMSE#TRPBF | PRODUCTION | |
|
Feb 4, 2020 - 20_0132 Laser Top Mark for 16-Lead MSOP Packages Assembled in ADPG and UTAC |
||
| LT3975EMSE#PBF | PRODUCTION | |
| LT3975EMSE#TRPBF | PRODUCTION | |
| LT3975HMSE#PBF | PRODUCTION | |
| LT3975HMSE#TRPBF | PRODUCTION | |
| LT3975IMSE#PBF | PRODUCTION | |
| LT3975IMSE#TRPBF | PRODUCTION | |
This is the most up-to-date revision of the Data Sheet.
Software Resources
Can't find the software or driver you need?
Request a Driver/SoftwareHardware Ecosystem
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|---|---|---|
| Hot Swap Controllers 1 | ||
| LT4363 | RECOMMENDED FOR NEW DESIGNS | High Voltage Surge Stopper with Current Limit |
| Ideal Diodes and PowerPath Controllers 1 | ||
| LTC4417 | RECOMMENDED FOR NEW DESIGNS | Prioritized PowerPath™ Controller |
| Oscillators 1 | ||
| LTC6908 | Resistor Set SOT-23 Oscillator with Spread Spectrum Modulation | |
Tools & Simulations
LTspice 1
Models for the following parts are available in LTspice:
- LT3975
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
LT3975 Demo Board I 4.3V ≤ VIN ≤ 42V; VOUT = 3.3V @ 2.5A