LT8647

Name: LT8647
Brand: Analog Devices
Price: 4.44 USD
Availability: InStock

RECOMMENDED FOR NEW DESIGNS

65V, 7A/8A Peak Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current

Data Sheet (Rev. B) Product Selection Table

Part Models: 1
1ku List Price: Starting From $4.44

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Overview

Silent Switcher^® Architecture
- Ultralow EMI Emissions
- Optional Spread Spectrum 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: 3.4V to 65V
7A Maximum Continuous Output, 8A Peak Transient Output
Ultralow Quiescent Current Burst Mode® Operation

2.5μA IQ Regulating 12V_IN to 3.3V_OUT
Output Ripple < 10mV_P-P

Fast Minimum Switch On-Time: 40ns
Low Dropout Under All Conditions: 60mV at 1A
Adjustable and Synchronizable: 200kHz to 2.2MHz
Peak Current Mode Operation
Output Soft-Start and Tracking
Small 27-Lead 6mm × 3mm Flip chip 2 quad flat no-lead (FC2QFN) Package

Part Models: 1
1ku List Price: Starting From $4.44

Documentation

Data Sheet 1

LT8647: 65V, 7A/8A Peak Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current Data Sheet (Rev.B) 08/08/2025

User Guide 1

EVAL-LT8647-AZ User Guide: LT8647: 65V, 7A (8A Peak) Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current (Rev.0) 07/29/2025

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
LT8647RCPZ-RL	27-Lead LFCSP (3 mm x 6mm x 0.75 mm w/EP)	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys

Software Resources

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Tools & Simulations

LTspice

Models for the following parts are available in LTspice:

LT8647

LTpowerCAD

Design tools for the following parts are available in LTpowerCAD:

LT8647

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

LT8647: 65V, 7A (8A Peak) Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current

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Features and Benefits

5.6V–65V Operating Input Voltage
- Reduced EMI emissions for CISPR 32 Class B
Delivers up to 7A (Maximum Continuous) and 8A (Peak Transient) Output Current
Configurable SYNC pin for Pulse-skipping Mode, Burst Mode, Spread Spectrum, and external Frequency Synchronization
Optional Transient Response Circuit
Optimized PCB Layout

Product Details

Demonstration circuit EVAL-LT8647-AZ is a 65V, 7A micropower synchronous step-down Silent Switcher^® with spread spectrum frequency modulation featuring the LT8647. The demo board is designed for a 5V output from a 5.6V to 65V input. The wide input range allows a variety of input sources, such as industrial supplies. The LT8647 is a compact, ultralow-emission, high-efficiency, and high-speed synchronous monolithic step-down switching regulator.- The integrated power switches and inclusion of all necessary circuitry reduce the component count and solution size. Special Silent Switcher architecture minimizes Electromagnetic interference (EMI) /Electromagnetic compatibility (EMC) emissions. Selectable spread spectrum mode can further improve EMI/EMC performance. Ultralow 2.5μA quiescent current in Burst Mode® operation achieves high efficiency at very light loads. A fast minimum on-time of 40ns enables high V_IN to low V_OUT conversion at high frequency.

The LT8647 switching frequency can be programmed via an oscillator resistor or external clock over a 200kHz to 2.2MHz range. The default frequency of the demo circuit EVAL-LT8647-AZ is 2MHz. The SYNC pin on the demo board is grounded (JP1 at BURST position) by default for low ripple Burst Mode operation. Spread spectrum mode and pulse-skipping mode can be selected, respectively, by moving the JP1 shunt. To synchronize to an external clock, move JP1 to SYNC and apply the external clock to the SYNC terminal.

The LT8647 data sheet gives a complete description of the part, operation, and application information. The data sheet must be read in conjunction with this demo manual for the demo circuit EVAL-LT8647-AZ. The LT8647 is assembled in a 3mm × 6mm, Flip chip 2 quad flat no-lead (FC2QFN) package with exposed pads for low thermal resistance. The layout recommendations for low EMI operation and maximum thermal performance are available in the data sheet section Low EMI Printed circuit board (PCB) Layout and Thermal Considerations.

Design files for this circuit board are available at Product Evaluation Boards and Kits | Design Center | Analog Devices.