LTC3643

RECOMMENDED FOR NEW DESIGNS

2A Bidirectional Power Backup Supply

Data Sheet (Rev. E) Product Selection Table

Part Models: 6
1ku List Price: Starting From $5.31

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Overview

Bidirectional Synchronous Boost Capacitor Charger/Buck Regulator for System Backup
Wide Input Voltage Range: 3V to 17V
Up to 40V Capacitor Voltage Storage for High Energy Backup
2A Maximum CAP Charge Current
Integrated Power N-Channel MOSFETs (150mΩ Top and 75mΩ Bottom)
Integrated Power N-Channel MOSFET for Output/CAP Disconnect (50mΩ)

Input Current Limit During Charging
Fast 1MHz Switching Frequency
±1% Reference Accuracy for System Voltage Regulation
Indicator Outputs for Charge Status and Input Power Fail
Low Profile 24-lead 3mm × 5mm QFN Package
AEC-Q100 Qualified for Automotive Applications

The LTC3643 is a bidirectional synchronous step-up charger and step-down converter which efficiently charges a capacitor array up to 40V from an input supply between 3V to 17V. When the input supply falls below the programmable power-fail threshold, the step-up charger operates in reverse as a synchronous step-down regulator to power the system rail from the backup capacitor during this power interuption/failure condition.

When charging the backup capacitor, an external low-value sense resistor may be used to maintain an accurate current limit from the input supply or implement PowerPath^™ functionality.

The step-down converter operates at a 1MHz switching frequency, allowing small external components to be used. Low quiescent current during regulation maximizes the energy usage from the backup capacitor.

Applications

Backup Capacitor Systems
Power Failure Backup Systems
Solid-State Drives
Automotive

Part Models: 6
1ku List Price: Starting From $5.31

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
LTC3643EUDD#PBF	24-Lead QFN (3mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3643EUDD#TRPBF	24-Lead QFN (3mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3643IUDD#PBF	24-Lead QFN (3mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3643IUDD#TRPBF	24-Lead QFN (3mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3643IUDD#WPBF	24-Lead QFN (3mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3643IUDD#WTRPBF	24-Lead QFN (3mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Apr 11, 2019 - 19_0067 Notification of Wafer Fab Location Change for 0.35 BCD Process
		PCN19_0067_Form Material_Report Delta Qualification Matrix Qualification Results Summary Detailed Parts List Other
LTC3643EUDD#PBF	PRODUCTION
LTC3643EUDD#TRPBF	PRODUCTION
LTC3643IUDD#PBF	PRODUCTION
LTC3643IUDD#TRPBF	PRODUCTION

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

Software Resources

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Hardware Ecosystem

Parts	Product Life Cycle	Description
Battery Charger ICs 1
LTC4040	RECOMMENDED FOR NEW DESIGNS	2.5A Battery Backup Power Manager
Switching Regulators & Controllers 2
LTC3110	RECOMMENDED FOR NEW DESIGNS	2A Bidirectional Buck-Boost DC/DC Regulator and Charger/Balancer
LTC3128	RECOMMENDED FOR NEW DESIGNS	3A Monolithic Buck-Boost Supercapacitor Charger and Balancer with Accurate Input Current Limit

Tools & Simulations

LTspice 1

LTC3643 Demo Circuit - Bidirectional Charger/Regulator for System Power Backup (3-17V to 5V @ 200mA)

Models for the following parts are available in LTspice:

LTC3643

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

LTC3643 Demo Board | 2A, Bidirectional 40V Boost Charger/Buck Back-Up Power Regulator, 3V ≤ VIN ≤ 17V (Boost), VOUT = 5V @ 2A/3A/4A (Buck)

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Product Details

Demonstration circuit 2220A is a 2A, bidirectional charger/regulator featuring the LTC3643, a bidirectional synchronous step-up charger and step-down converter. DC2220A implements backup by charging a storage capacitor up to approximately 40V in boost mode, when the input voltage is present. It discharges the storage capacitor in buck mode, providing a regulated load voltage 5V when the input is removed. Its wide voltage range, both in capacitor charger mode and in system backup mode, makes it well suited to a wide variety of applications. The ability of the LTC3643 to boost an input rail to a relatively high voltage of 40V, combined with the DC2220 option of adding external capacitor banks, makes this regulator an excellent choice for energy storage applications.