LT8640/LT8640-1 - 42V, 5A Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current
- Silent Switcher® Architecture
- Ultralow EMI/EMC Emissions
- Spread Spectrum Frequency Modulation
- High Efficiency at High Frequency
- Up to 96% Efficiency at 1MHz
- Up to 95% Efficiency at 2MHz
- Wide Input Voltage Range: 3.4V to 42V
- 5A Maximum Continuous Output, 7A Peak Transient Output
- Ultralow Quiescent Current Burst Mode® Operation
- 2.5μA IQ Regulating 12VIN to 3.3VOUT
- Output Ripple < 10mVP-P
- Fast Minimum Switch-On Time: 35ns
- Low Dropout Under All Conditions: 100mV at 1A
- Forced Continuous Mode (LT8640-1 Only)
- 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 data available for specific packages
The LT®8640/LT8640-1 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 LT8640/LT8640-1 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 opendrain PG pin signals when the output is in regulation. The SYNC/MODE pin selects between Burst Mode operation, spread spectrum mode, synchronization to an external clock, and either pulse-skipping (LT8640) or forced continuous mode (LT8640-1). 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.
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
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Demo BoardsLinear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.
|DC2202A||LT8640EUDC Demo Board | µPower Buck Silent Switcher, 5.7V ≤ VIN ≤ 42V; Vout = 5V @ 5A||$249.00|
Designed for Automotive and Transportation ApplicationsAEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page
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- Automotive and Industrial Supplies
- General Purpose Step-Down
- GSM Power Supplies
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