The LT8640/LT8640-1 step-down regulator features Silent Switcher architecture designed to minimize EMI/EMC emissions while delivering high efficiency at frequencies up to 3MHz. An ultralow 2.5µA quiescent current—with the output in full regulation—enables applications requiring highest efficiency at very small load currents.
The LT8640/LT8640-1 allows high VIN to low VOUT conversion at high frequency with a fast minimum top switch on-time of 30ns. 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).
PackageSYNC/MODE ≠ 0VC COMPH-GRADECLKOUTINTERNAL CAPSLT8640QFNPulse-SkippingInternalYesNoNoLT8640-1QFNFCMInternalYesNoNoLT8640SLQFNFCMInternalNoYesYesLT8643SLQFNFCMExternalNoYesYesLT8640S-2LQFNFCMInternalYesYesNoLT8643S-2LQFNFCMExternalYesYesNo
Feature
Silent Switcher® Architecture
High Efficiency at High Frequency
Up to 96% Efficiency at 1MHz, 12VIN to 5VOUT
Up to 95% Efficiency at 2MHz, 12VIN to 5VOUT
Wide Input Voltage Range: 3.4V to 42V
5A Maximum Continuous Output, 7A Peak Transient Output
Ultralow Quiescent Current Burst Mode® Operation
Fast Minimum Switch On-Time: 30ns
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 and Side Wettable QFN
Applications
Catalogue
FPGA / CPLD
Memory
MOS 
MCU 
DSP
OCEP
Secondary 
Other 
