LTC3128

RECOMMENDED FOR NEW DESIGNS

3A Monolithic Buck-Boost Supercapacitor Charger and Balancer with Accurate Input Current Limit

Part Models: 8
1ku List Price: Starting From $4.72

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Overview

±2% Accurate Average Input Current Limit Programmable Up to 3A
Programmable Maximum Capacitor Voltage Limit
Active Charge Balancing for Fast Charging of Unmatched Capacitors
Charges Single or Stacked Capacitors
V_IN Range: 1.73V to 5.5V
V_OUT Range: 1.8V to 5.5V
<2μA Quiescent Current from V_OUTWhen Charged
Output Disconnect in Shutdown: <1μA I_Q Shutdown
Power-Good Comparator
Power Failure Indicator
Thermally Enhanced 20-Lead (4mm × 5mm × 0.75mm) QFN and 24-Lead TSSOP Packages

The LTC3128 is a highly efficient, buck-boost DC/DC supercapacitor charger. It operates efficiently from input voltages above, below or equal to the output voltage. The LTC3128 incorporates accurate programmable average input current limit, active charge balancing and programmable maximum capacitor voltage. This combination of features makes the LTC3128 ideal for safely charging and protecting large capacitors in backup power systems. The input current limit and maximum capacitor voltage are each programmed using a single resistor. Average input current is accurately controlled over a 0.5A to 3A programmable range while the individual maximum capacitor voltage can be set from 1.8V to 3.0V.

Other features of the LTC3128 include <2μA quiescent current from V_OUT in Burst Mode^®operation, accurate power-good and power failure indicators, and thermal overload protection. The LTC3128 is offered in low profile, thermally enhanced 20-Lead 4mm × 5mm × 0.75mm QFN and 24-Lead TSSOP packages.

Applications

Supercapacitor Based Backup Power
Memory Backup
Servers, RAID, RF Systems
Industrial, Communications, Computing

Part Models: 8
1ku List Price: Starting From $4.72

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
LTC3128EFE#PBF	24-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3128EFE#TRPBF	24-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3128EUFD#PBF	20-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3128EUFD#TRPBF	20-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3128IFE#PBF	24-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3128IFE#TRPBF	24-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3128IUFD#PBF	20-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3128IUFD#TRPBF	20-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Feb 14, 2025 - 25_0016 Bond Wire Change from Gold to Copper Wire (Notification Only)
		PCN25_0016_Form Material_Report Qualification Results Summary
LTC3128EFE#PBF	PRODUCTION
LTC3128EFE#TRPBF	PRODUCTION
LTC3128EUFD#PBF	PRODUCTION
LTC3128EUFD#TRPBF	PRODUCTION
LTC3128IFE#PBF	PRODUCTION
LTC3128IFE#TRPBF	PRODUCTION
LTC3128IUFD#PBF	PRODUCTION
LTC3128IUFD#TRPBF	PRODUCTION
Apr 6, 2022 - 22_0068 Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL
		PCN22_0068_Form Material_Report Delta Qualification Matrix
LTC3128EFE#PBF	PRODUCTION
LTC3128EFE#TRPBF	PRODUCTION
LTC3128IFE#PBF	PRODUCTION
LTC3128IFE#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 1
LTC3110	RECOMMENDED FOR NEW DESIGNS	2A Bidirectional Buck-Boost DC/DC Regulator and Charger/Balancer

Tools & Simulations

LTspice

Models for the following parts are available in LTspice:

LTC3128

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

LTC3128 Demo Board | 2-Cell Supercap Charger and Balancer: 1.72VIN to 5.5VIN @ up to 3A

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Product Details

Demonstration circuit 1887 is a DC/DC supercapacitor buck-boost charger and balancer converter featuring the LTC3128. The DC1887A operates over 1.72V to 5.5V input and charges the output up to 5.5V. Also, the LTC3128 has 2% precision input current limit, which allows the circuit to operate effectively with current limited input power sources like the USB. The 1.2MHz switching frequency operation results in a small and efficient circuit. The converter provides high output voltage accuracy (typically ±2%) over a 1.72V to 5.5V input. The demonstration circuit can be easily modified to generate different output voltages.

Resources

DC1887A - Design Files
4/14/2014

DC1887A - Schematic
4/14/2014

DC1887A - Demo Manual
4/14/2014

Latest Discussions

2 Years Ago

LTC3128

Overview

Documentation

Data Sheet 1

Reliability Data 1

User Guide 1

Technical Articles 1

Product Selector Card 1

Solutions Bulletin & Brochure 1