LT8641
RECOMMENDED FOR NEW DESIGNS65V, 3.5A Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current
- Part Models
- 12
- 1ku List Price
- Starting From $6.57
Overview
- Silent Switcher® Architecture
- Ultralow EMI Emissions
- Spread Spectrum Frequency Modulation
- High Efficiency at High Frequency
- Up to 95% Efficiency at 1MHz, 12VIN to 5VOUT
- Up to 94% Efficiency at 2MHz, 12VIN to 5VOUT
- Wide Input Voltage Range: 3V to 65V
- 3.5A Maximum Continuous Output, 5A Peak Transient Output
- Fast Minimum Switch-On Time: 35ns
- Ultralow Quiescent Current Burst Mode® Operation
- 2.5μA IQ Regulating 12VIN to 3.3VOUT
- Output Ripple < 10mVP-P
- Low Dropout Under All Conditions: 130mV at 1A
- Safely Tolerates Inductor Saturation in Overload
- Adjustable and Synchronizable: 200kHz to 3MHz
- Peak Current Mode Operation
- Output Soft-Start and Tracking
- Small 18-Lead 3mm × 4mm QFN
- AEC-Q100 Qualified for Automotive Applications
The LT8641 step-down regulator features Silent Switcher architecture designed to minimize EMI/EMC emissions while delivering high efficiency at frequencies up to 3MHz. Assembled in a 3mm × 4mm QFN, the monolithic construction with integrated power switches and inclusion of all necessary circuitry yields a solution with a minimal PCB footprint. An ultralow 2.5μA quiescent current—with the output in full regulation—enables applications requiring highest efficiency at very small load currents. Transient response remains excellent and output voltage ripple is below 10mVP-P at any load, from zero to full current.
The LT8641 allows high VIN to low VOUT conversion at high frequency with a fast minimum top switch on-time of 35ns. Operation is safe in overload even with a saturated inductor.
Essential features are included and easy to use: An open-drain PG pin signals when the output is in regulation. The SYNC/MODE pin selects between Burst Mode, pulse-skipping, or spread spectrum mode, and also allows synchronization to an external clock. Soft-start and tracking functionality is accessed via the TR/SS pin. An accurate enable threshold can be set using the EN/UV pin and a resistor at the RT pin programs switch frequency.
APPLICATIONS
- Automotive and Industrial Supplies
- General Purpose Step-Down
- GSM Power Supplies
Documentation
Data Sheet 1
User Guide 1
Technical Articles 2
Video 1
Brochure 1
Book & eBook 1
Rarely Asked Question 1
Webcast 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 |
|---|---|---|---|
| LT8641EUDC#PBF | 20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP) | ||
| LT8641EUDC#TRPBF | 20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP) | ||
| LT8641HUDC#PBF | 20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP) | ||
| LT8641HUDC#TRPBF | 20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP) | ||
| LT8641HUDC#WPBF | 20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP) | ||
| LT8641HUDC#WTRPBF | 20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP) | ||
| LT8641IUDC#PBF | 20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP) | ||
| LT8641IUDC#TRPBF | 20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP) | ||
| LT8641IUDC#WPBF | 20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP) | ||
| LT8641IUDC#WTRPBF | 20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP) | ||
| LT8641JUDC#WPBF | 20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP) | ||
| LT8641JUDC#WTRPBF | 20(18)-Lead QFN (3mm x 4mm x 0.75mm w/ EP) |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
Sep 30, 2020 - 20_0293 Test Site Transfer from Analog Devices Singapore to UTAC Thailand |
||
| LT8641EUDC#PBF | PRODUCTION | |
| LT8641EUDC#TRPBF | PRODUCTION | |
| LT8641HUDC#PBF | PRODUCTION | |
| LT8641HUDC#TRPBF | PRODUCTION | |
| LT8641IUDC#PBF | PRODUCTION | |
| LT8641IUDC#TRPBF | PRODUCTION | |
|
Apr 11, 2019 - 19_0067 Notification of Wafer Fab Location Change for 0.35 BCD Process |
||
| LT8641EUDC#PBF | PRODUCTION | |
| LT8641EUDC#TRPBF | PRODUCTION | |
| LT8641HUDC#PBF | PRODUCTION | |
| LT8641HUDC#TRPBF | PRODUCTION | |
| LT8641IUDC#PBF | PRODUCTION | |
| LT8641IUDC#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:
- LT8641
LTpowerCAD 1
- LT8641 Project - 65V, 3.5A Monolithic µPower Synchronous Buck Silent Switcher (5.5-65V to 5V @ 3.5A)
Design tools for the following parts are available in LTpowerCAD:
- LT8641
- LT8641A
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.
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
Evaluation Kits
LT8641 Demo Board | Synchronous Buck, Silent Switcher, 5.5V ≤ VIN ≤ 65V, VOUT = 5V @ 3.5A, fSW = 2MHz