LT8641A

Name: LT8641A
Brand: Analog Devices
Price: 3.28 USD
Availability: InStock

RECOMMENDED FOR NEW DESIGNS

65V, 3.5A/5A Peak Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current

Data Sheet (Rev. 0) Product Selection Table

Part Models: 4
1ku List Price: Starting From $3.28

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Overview

Silent Switcher^® Architecture
- Ultralow EMI Emissions
- Spread Spectrum Frequency Modulation
High Efficiency at High Frequency
- Up to 95% Efficiency at 1MHz, 12V_IN to 5V_OUT
- Up to 94% Efficiency at 2MHz, 12V_IN to 5V_OUT
Wide Input Voltage Range: 3V to 65V
3.5A Maximum Continuous, 5A Peak Transient Output
Ultralow Quiescent Current Burst Mode^® Operation
- 2.5μA I_Q Regulating 12V_IN to 3.3V_OUT
- Output Ripple < 10mV_P-P

Fast Minimum Switch On-Time: 35ns
- True 2MHz Operation for 24V_IN Systems
Low Dropout Under All Conditions: 130mV at 1A
Safely Tolerates Inductor Saturation in Overload
Adjustable and Synchronizable: 200kHz to 3MHz
Output Soft-Start and Tracking
Small 18-Lead 3mm × 4mm Side Wettable QFN with Improved Solder Joint Reliability
AEC-Q100 Qualified for Automotive Applications

Part Models: 4
1ku List Price: Starting From $3.28

Documentation

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
LT8641ARUDCM#PBF	20(18)-Lead Plastic Side Wettable QFN (3mm × 4mm)	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8641ARUDCM#TRPBF	20(18)-Lead Plastic Side Wettable QFN (3mm × 4mm)	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8641ARUDCM#WPBF	20(18)-Lead Plastic Side Wettable QFN (3mm × 4mm)	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8641ARUDCM#WTRPBF	20(18)-Lead Plastic Side Wettable QFN (3mm × 4mm)	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Tools & Simulations

LTspice

Models for the following parts are available in LTspice:

LT8641

LTpowerCAD

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.

Evaluation Kits

65V, 3.5A/5A Peak Synchronous Step-Down Silent Switcher

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Product Details

Evaluation circuit EVAL-LT8641A-AZ is a 65V, 3.5A/5A peak synchronous step-down Silent Switcher^® with spread spectrum frequency modulation featuring the LT8641A. The demo board is designed for 5V output from a 5.5V to 65V input. The wide input range allows a variety of input sources, such as automotive batteries and industrial supplies. The LT8641A is a compact, ultralow emission, high efficiency, high speed synchronous monolithic step-down switching regulator. Top and bottom power switches, compensation components, and other necessary circuits inside the LT8641A minimize external components and simplify design. The special Silent Switcher architecture minimizes EMI emissions. The selectable spread spectrum mode can further improve EMI performance. Ultralow 2.5μA quiescent current in Burst Mode^® operation achieves high efficiency at very light loads. Fast minimum on-time of 35ns enables high V_IN to low V_OUT conversion at high frequency.

The LT8641A switching frequency can be programmed either through oscillator resistor or external clock over a 200kHz to 3MHz range. The default frequency of the evaluation board is 2MHz. The SYNC pin on the evaluation board is grounded by JP1 for low ripple burst mode operation. Move JP1 to PULSE SKIPPING position
to change the operation mode to pulse-skipping operation. Once JP1 is on SPREAD SPECTRUM position, V_CC is applied to the SYNC pin for low EMI spread spectrum operation. To synchronize to an external clock, move JP1 to SYNC and apply the external clock to the SYNC turret. Figure 1 in the user guide shows the efficiency of the circuit at 12V and 24V input in Burst Mode operation.

Figure 2 in the user guide shows EMI performances of the board (with EMIfilter). The red lines in Figure 2 are CISPR25 Class5 peak limit. The figure shows that the circuit passes the test with a wide margin. To achieve EMI/EMC performance, as shown in Figure 2, the input EMI filter is required, and the input voltage should be applied at the VEMI turret.

The LT8641A data sheet gives a complete description of the part, operation, and application information. Read the data sheet in conjunction with the user guide for EVAL-LT8641A-AZ. The LT8641A is assembled in a 3mm × 4mm plastic QFN package with exposed pad for low thermal resistance. The layout recommendations for low EMI operation and maximum thermal performance are available in the “Low EMI PCB Layout and Thermal Considerations” and “Peak Output Current” sections of the data sheet.