LT3991
PRODUCTION55V, 1.2A Step-Down Regulator with 2.8μA Quiescent Current
- Part Models
- 16
- 1ku List Price
- Starting From $4.48
Overview
- Ultralow Quiescent Current: 2.8μA IQ Regulating 12VIN to 3.3VOUT
- Fixed Output Voltages: 3.3V, 5V 2.1μA IQ Regulating 12VIN
- Low Ripple Burst Mode® Operation: Output Ripple < 15mVP-P
- Wide Input Voltage Range: 4.3V to 55V
- 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 CapabilityV
- Internal Compensation
- Saturating Switch Design: 0.44Ω On-Resistance
- Output Voltage: 1.19V to 30V
- Small Thermally Enhanced 10-Pin MSOP Package and (3mm × 3mm) DFN Packages
The LT3991 is an adjustable frequency monolithic buck switching regulator that accepts a wide input voltage range up to 55V. 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 0.44Ω 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 LT3991, 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 LT3991 is available in small 10-pin MSOP and 3mm × 3mm DFN packages with exposed pads for low thermal resistance.
Applications
- Automotive Battery Regulation
- Power for Portable Products
- Industrial Supplies
Documentation
Data Sheet 1
User Guide 1
Technical Articles 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 |
|---|---|---|---|
| LT3991EDD#PBF | 10-Lead DFN (3mm x 3mm w/ EP) | ||
| LT3991EDD#TRPBF | 10-Lead DFN (3mm x 3mm w/ EP) | ||
| LT3991EMSE#PBF | 10-Lead MSOP w/ EP | ||
| LT3991EMSE#TRPBF | 10-Lead MSOP w/ EP | ||
| LT3991EMSE-3.3#PBF | 10-Lead MSOP w/ EP | ||
| LT3991EMSE-3.3#TRPBF | 10-Lead MSOP w/ EP | ||
| LT3991EMSE-5#PBF | 10-Lead MSOP w/ EP | ||
| LT3991EMSE-5#TRPBF | 10-Lead MSOP w/ EP | ||
| LT3991IDD#PBF | 10-Lead DFN (3mm x 3mm w/ EP) | ||
| LT3991IDD#TRPBF | 10-Lead DFN (3mm x 3mm w/ EP) | ||
| LT3991IMSE#PBF | 10-Lead MSOP w/ EP | ||
| LT3991IMSE#TRPBF | 10-Lead MSOP w/ EP | ||
| LT3991IMSE-3.3#PBF | 10-Lead MSOP w/ EP | ||
| LT3991IMSE-3.3#TRPBF | 10-Lead MSOP w/ EP | ||
| LT3991IMSE-5#PBF | 10-Lead MSOP w/ EP | ||
| LT3991IMSE-5#TRPBF | 10-Lead MSOP w/ EP |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
Jun 5, 2024 - 24_0003 Epoxy Change from Henkel 8290 to 8290A for MSOP Package (2) |
||
| LT3991EMSE#PBF | PRODUCTION | |
| LT3991EMSE#TRPBF | PRODUCTION | |
| LT3991EMSE-3.3#PBF | PRODUCTION | |
| LT3991EMSE-3.3#TRPBF | PRODUCTION | |
| LT3991EMSE-5#PBF | PRODUCTION | |
| LT3991EMSE-5#TRPBF | PRODUCTION | |
| LT3991IMSE#PBF | PRODUCTION | |
| LT3991IMSE#TRPBF | PRODUCTION | |
| LT3991IMSE-3.3#PBF | PRODUCTION | |
| LT3991IMSE-3.3#TRPBF | PRODUCTION | |
| LT3991IMSE-5#PBF | PRODUCTION | |
| LT3991IMSE-5#TRPBF | PRODUCTION | |
|
Feb 4, 2020 - 20_0130 Laser Top Mark Conversion for 10-Lead MSOP Packages Assembled in ADPG and UTAC |
||
| LT3991EMSE#PBF | PRODUCTION | |
| LT3991EMSE#TRPBF | PRODUCTION | |
| LT3991EMSE-3.3#PBF | PRODUCTION | |
| LT3991EMSE-3.3#TRPBF | PRODUCTION | |
| LT3991EMSE-5#PBF | PRODUCTION | |
| LT3991EMSE-5#TRPBF | PRODUCTION | |
| LT3991IMSE#PBF | PRODUCTION | |
| LT3991IMSE#TRPBF | PRODUCTION | |
| LT3991IMSE-3.3#PBF | PRODUCTION | |
| LT3991IMSE-3.3#TRPBF | PRODUCTION | |
| LT3991IMSE-5#PBF | PRODUCTION | |
| LT3991IMSE-5#TRPBF | PRODUCTION | |
This is the most up-to-date revision of the Data Sheet.
Software Resources
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Tools & Simulations
LTspice 1
Models for the following parts are available in LTspice:
- LT3991
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.