LT8603

PRODUCTION

42V, Low I_Q, Quad Output Triple Monolithic Buck Converter and Boost Controller

Data Sheet (Rev. C) Product Selection Table

Part Models: 12
1ku List Price: Starting From $3.53

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Overview

Flexible Power Supply System Capable of Four Regulated Outputs with V_BATT << V_OUT
Two High Voltage Synchronous Buck Regulators
- 3V to 42V Input Voltage Range
- Output Currents Up to 2.5A and 1.5A
One Low Voltage Synchronous Buck Regulator
- 2.6V to 5.5V Input Voltage Range
- Output Currents Up to 1.8A
One Boost Controller Allows Buck Converters to Regulate with V_BATT << V_OUT

Selectable Burst Mode^® Operation Allows Low 28µA I_Q with High Voltage Channels Active
Programmable Power-On Reset
Individual Channel Power Good Indicators
Step-Down Switching Frequency: 250kHz to 2.2MHz
Available in 40-Lead QFN (6mm × 6mm) Package
AEC-Q100 Qualified for Automotive Applications

The LT8603 is a highly flexible, quad output regulator combining two high input voltage capable monolithic step-down switching regulators, one low input voltage capable monolithic step-down regulator, and a boost controller to satisfy a wide range of applications while occupying minimal board space.

With the boost controller configured to supply the chip V_IN supply, the LT8603 produces three precisely regulated outputs even when the boost input voltage falls significantly below the regulated output voltages, such as during an automotive cold crank scenario. Alternatively, with the boost controller driven from one of the step-down regulator outputs or configured as a SEPIC, the LT8603 provides four precisely regulated outputs over a wide input voltage range.

The LT8603 provides robust regulation by including a cycle-by-cycle current limit for all step-down regulators, thermal shutdown, and a boost controller that can tolerate reverse battery connections and negative transient input voltages down to –42V.

Applications

Automotive Stop-Start and Cold Crank Ride Through
Last-Gasp CPU Power Hold-Up
Industrial Controls and Power Supplies

Part Models: 12
1ku List Price: Starting From $3.53

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
LT8603EUJ#PBF	40-Lead QFN (6mm x 6mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8603EUJ#TRPBF	40-Lead QFN (6mm x 6mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8603EUJ#WPBF	40-Lead QFN (6mm x 6mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8603EUJ#WTRPBF	40-Lead QFN (6mm x 6mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8603IUJ#PBF	40-Lead QFN (6mm x 6mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8603IUJ#TRPBF	40-Lead QFN (6mm x 6mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8603IUJ#WPBF	40-Lead QFN (6mm x 6mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8603IUJ#WTRPBF	40-Lead QFN (6mm x 6mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8603JUJ#PBF	40-Lead QFN (6mm x 6mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8603JUJ#TRPBF	40-Lead QFN (6mm x 6mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8603JUJ#WPBF	40-Lead QFN (6mm x 6mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT8603JUJ#WTRPBF	40-Lead QFN (6mm x 6mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Apr 17, 2025 - 25_0043 Change of Gold to Copper Wire and BOM (Automotive)
		PCN25_0043_Form Material_Report Delta Qualification Matrix Qualification Results Summary
LT8603EUJ#PBF	PRODUCTION
LT8603EUJ#TRPBF	PRODUCTION
LT8603EUJ#WPBF	PRODUCTION
LT8603EUJ#WTRPBF	PRODUCTION
LT8603IUJ#PBF	PRODUCTION
LT8603IUJ#TRPBF	PRODUCTION
LT8603IUJ#WPBF	PRODUCTION
LT8603IUJ#WTRPBF	PRODUCTION
LT8603JUJ#PBF	PRODUCTION
LT8603JUJ#TRPBF	PRODUCTION
LT8603JUJ#WPBF	PRODUCTION
LT8603JUJ#WTRPBF	PRODUCTION

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

Software Resources

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Tools & Simulations

LTspice 1

LT8603 Demo Circuit - Cold Crank Tolerant Automotive Triple Output Supply (3-42V to 5V @ 1.5A, 3.3V @ 2.5A, 1.8V @ 1.8A)

Models for the following parts are available in LTspice:

LT8603

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

LT8603 Demo Board | 42V, Quad Output Triple Monolithic Buck Converter and Boost Controller

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Product Details

Demonstration Circuit 2114A features the LT8603 with triple monolithic buck regulators and a boost controller. The demo circuit is designed for 8.0V, 5.0V, 3.3V, and 1.8V outputs from a nominal 12V input. The 4th channel is set as a boost converter and is powered from a wide input range with output VOUT4 regulated at 8V if 3V < VIN < 8.5V. It works as diode pass through if the input is above 8.5V. The two high voltage buck regulators are powered from the boost converter. VOUT1 is regulated at 5V with 1.5A maximum output load current, and VOUT2 is at 3.3V with 2.5A maximum output load current. Thanks to the pre-boost converter, they can ride through a cold crank in automotive applications while providing constant output voltages 5V and 3.3V. The low voltage buck is powered from the VOUT2 (3.3V), and the output VOUT3 is regulated at 1.8V with 1.8A maximum load current.

Resources

DC2114A - Schematic
1/10/2018

DC2114A - Design Files
1/10/2018

DC2114A - Demo Manual
1/10/2018

LT8603 Demo Board | 42V, Low IQ, Quad Output Triple Monolithic Buck Converter with Boost Channel as SEPIC

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Product Details

Demonstration circuit 2469A features the LT8603 with triple monolithic buck regulators and the boost channel as SEPIC. The demo circuit is designed for 8V, 5V, 3.3V, and 1.8V outputs from a nominal 12V input. The 4th channel is set as a SEPIC converter and its output is regulated at 8V over a wide input range. The two high voltage buck regulators are powered from V_OUT4. V_OUT1 is regulated at 5V with 1.5A maximum output load current, and V_OUT2 is at 3.3V with 2.5A maximum output load current. The low voltage buck is powered from V_OUT2 (3.3V), and the output V_OUT3 is regulated at 1.8V with 1.8A maximum load current. Thanks to the SEPIC converter, all four outputs can ride through a cold crank in automotive applications while providing regulated output voltages.

Resources

DC2469A - Schematic
1/19/2018

DC2469A - Demo Board Manual
1/19/2018

DC2469A - Design Files
1/19/2018

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LT8603

Overview

Documentation

Data Sheet 1

Reliability Data 1

User Guide 2

Design Note 2

Technical Articles 2

Analog Dialogue 1

Software Resources

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Tools & Simulations

LTspice 1

Models for the following parts are available in LTspice:

Evaluation Kits

Product Details

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