New Content (2)
Overview
Features and Benefits
- Silent Switcher®2 Architecture
- Ultralow EMI Emissions
- Optional Spread Spectrum Modulation
- Two High Voltage Synchronous Buck Regulators
- 3V to 42V Input Voltage Range
- Output Currents Up to 2.5A per Channel
- Channels May Be Connected in Parallel Using a Single Inductor
- Two Low Voltage Synchronous Buck Regulators
- 3V to 8V Input Voltage Range
- Output Currents Up to 4A per Channel
- Channels May Be Connected in Parallel Using a Single Inductor
- 12μA IQ All Channels Active and No-Load
- Flexible Supply Sequencing and Control
- Adjustable and Synchronizable: 350kHz to 3MHz
- Available in 36-Lead LQFN (5mm × 6mm) AEC-Q100 Qualified for Automotive Applications
Product Details
The LT8685S is a highly flexible, four channel, current mode, monolithic regulator able to power a wide range of automotive and industrial applications while occupying minimal board space.
The LT8685S combines two 42V capable 2.5A buck regulators with two 8V capable 4A buck regulators. The two 42V regulators may be combined to provide up to 5A of output current using a single inductor. Similarly, the two 8V regulators may be combined to provide up to 8A of output current using a single inductor. Individual channel enable, track/soft-start and power good pins provide flexible power supply sequencing and control. The LT8685S features a Silent Switcher 2 architecture, plus selectable spread spectrum mode, to provide ultralow EMI/EMC emissions while delivering high efficiency at high switching frequencies.
The LT8685S incorporates thermal shutdown and individual channel cycle-by-cycle current limit for short circuit protection and robust operation.
APPLICATIONS
- Automotive Systems
- Industrial Controls and Power Supplies
Product Lifecycle
Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
Documentation & Resources
-
EVAL-LT8685S-AZ - Demo Manual (Rev. 0)10/25/2022
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Silent Switcher Technology8/15/2023
Tools & Simulations
LTspice
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.

Models for the following parts are available in LTspice:
LTpowerCAD
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.

Design tools for the following parts are available in LTpowerCAD:
Design Resources
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 Number | Material Declaration | Reliability Data | Pin/Package Drawing | CAD Symbols, Footprints & 3D Models |
---|---|---|---|---|
LT8685SRV#PBF | Material Declaration | Reliability Data | 36-Lead LQFN Package (5mm x 6mm) | |
LT8685SRV#TRPBF | Material Declaration | Reliability Data | 36-Lead LQFN Package (5mm x 6mm) | |
LT8685SRV#WPBF | Material Declaration | Reliability Data | 36-Lead LQFN Package (5mm x 6mm) | |
LT8685SRV#WTRPBF | Material Declaration | Reliability Data | 36-Lead LQFN Package (5mm x 6mm) | |
Wafer Fabrication Data |
Support & Discussions
Sample & Buy
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List Pricing
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Lead Times
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Sampling
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Evaluation Boards
Pricing displayed is based on 1-piece.
Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.
Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.