LT8641 Series

65V, 3.5A Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current

Catalog

65V, 3.5A Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current

Part	Synchronous Rectifier	Supplier Device Package	Output Configuration	Voltage - Input (Min) [Min]	Current - Output	Number of Outputs	Voltage - Output (Max) [Max]	Operating Temperature [Min]	Operating Temperature [Max]	Topology	Output Type	Voltage - Output (Min/Fixed)	Frequency - Switching [Max]	Frequency - Switching [Min]	Voltage - Input (Max) [Max]	Mounting Type	Function	Package / Case	Frequency - Switching	Main Purpose	Utilized IC / Part	Regulator Topology	Voltage - Input [Min]	Voltage - Input [Max]	Voltage - Output	Supplied Contents	Board Type	Outputs and Type	Outputs and Type
Analog Devices LT8641EUDC#PBF		20-QFN (3x4)	Positive	3 V	3.5 A	1	64.35 V	-40 °C	125 ¯C	Buck	Adjustable	0.8 V	2 MHz	210 kHz	65 V	Surface Mount	Step-Down	18 Leads 20-WFQFN Exposed Pad
Analog Devices EVAL-LT8641A-AZ					3.5 A														2 MHz	DC/DC Step Down	LT8641A	Buck	5.5 V	65 V	5 V	Board(s)	Fully Populated	Non-Isolated	1

Catalog

65V, 3.5A Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current

Key Features

• Silent Switcher®Architecture

• Ultralow EMI Emissions

• Spread Spectrum Frequency Modulation

• High Efficiency at High Frequency

• Up to 95% Efficiency at 1MHz, 12VINto 5VOUT

• Up to 94% Efficiency at 2MHz, 12VINto 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 IQRegulating 12VINto 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

Description

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-Pat any load, from zero to full current.The LT8641 allows high VINto low VOUTconversion 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.APPLICATIONSAutomotive and Industrial SuppliesGeneral Purpose Step-DownGSM Power Supplies