LT8645S-2

RECOMMENDED FOR NEW DESIGNS

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

Data Sheet (Rev. B) Product Selection Table

Part Models: 10
1ku List Price: Starting From $5.60

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Overview

Silent Switcher^® Architecture

Ultralow EMI Emissions
Optional Spread Spectrum Modulation

- 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
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: 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 32-Lead 6mm × 4mm LQFN Package
AEC-Q100 Qualified for Automotive Applications

The LT8645S-2 synchronous step-down regulator features Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. This performance makes the LT8645S-2 ideal for noise sensitive applications and environments.

The fast, clean, low-overshoot switching edges enable high efficiency operation even at high switching frequencies, leading to a small overall solution size. Peak current mode control with a 40ns minimum on-time allows high step-down ratios even at high switching frequencies.

Burst Mode^®operation enables ultralow standby current consumption, pulse-skipping mode allows full switching frequency at lower output loads, or spread spectrum operation can further reduce EMI emissions.

Applications

Automotive and Industrial Supplies
General Purpose Step-Down
GSM Power Supplies

Part Models: 10
1ku List Price: Starting From $5.60

Documentation

Data Sheet 1

LT8645S-2: 65V, 8A Synchronous Step-Down Silent Switcher with 2.5µA Quiescent Current Data Sheet (Rev.B) 09/03/2024

Design Note 1

Monolithic 65V , 8A Step-Down Regulators with Fast Transient Response and Ultralow EMI Emissions 09/01/2018

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
LT8645SEV-2#PBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8645SEV-2#TRPBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8645SEV-2#WPBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8645SEV-2#WTRPBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8645SHV-2#PBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8645SHV-2#TRPBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8645SHV-2#WPBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8645SJV-2#PBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8645SJV-2#TRPBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8645SJV-2#WPBF	32-Lead LQFN (6mm x 4mm x 0.94mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Sep 9, 2025 - 24_0002 Qualification of New Mold Compound, SMT Paste and Pillar Diameter Change for LT8645S, LT8645S-2, LT8646S
		PCN24_0002_Form Material_Report Qualification Results Summary Delta Qualification Matrix Other
LT8645SEV-2#PBF	PRODUCTION
LT8645SEV-2#TRPBF	PRODUCTION
LT8645SEV-2#WPBF	PRODUCTION
LT8645SHV-2#PBF	PRODUCTION
LT8645SHV-2#TRPBF	PRODUCTION
LT8645SHV-2#WPBF	PRODUCTION
LT8645SJV-2#PBF	PRODUCTION
LT8645SJV-2#TRPBF	PRODUCTION
LT8645SJV-2#WPBF	PRODUCTION

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

Software Resources

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Tools & Simulations

LTpowerCAD

Design tools for the following parts are available in LTpowerCAD:

LT8645S

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.

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