DS2731

NOT RECOMMENDED FOR NEW DESIGNS

Cache-Memory Battery-Backup Management IC

Complete Cache-Memory Battery-Backup IC Reduces System Cost, Component Count, and Footprint Over Current Solutions

Data Sheet (Rev. 1) Product Selection Table

Part Models: 2
1ku List Price: price unavailable

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Overview

Lithium Chemistry CCCV Charger
Adjustable Regulated Charging Up to 1.5A DC
Adjustable Charge Voltage from 3.8V to 4.6V
External and Internal Thermal Protection
Safety Timer Secondary Termination
LED Indicator Outputs
Detects Power Outage and Switches Between Normal Power and Backup Battery
Adjustable High-Efficiency Synchronous Buck Regulator with Skip Mode at Light Loads
Low-Power Consumption in Discharge Mode

The DS2731 is a complete power-management solution for modular backup applications. It is well-suited for 2.5V and below memory bus voltages, with an input voltage of 12V. The DS2731 includes an internal MOSFET switching power stage for charging a one-cell lithium chemistry battery. It has a fully integrated synchronous buck regulator capable of supplying up to 450mA of cache backup supply current, and the necessary logic and power devices for handling the switchover from system power to battery power. The battery charging method of the DS2731 is constant current/constant voltage (CCCV). Output voltage can be margined from 3.8V to 4.6V using a resistor-divider. Charge is terminated when the charging current falls below 5% of full charge current. Switchover to battery backup is initiated by an internal comparator and occurs automatically when a sensed-input voltage drops below 2.93V. At light loads, the 2MHz internal synchronous buck regulator operates in burst mode for maximum efficiency. All nonessential functions of the DS2731 are disabled while supplying holdup current to the cache memory, and the IC goes into very low-current dormant mode when the battery voltage drops below a user-settable threshold. The DS2731 keeps track of charge status and signals the user through open-drain I/O pins that can be used to drive LEDs.

Applications

RAID Server Memory Card

Part Models: 2
1ku List Price: price unavailable

Documentation

Data Sheet 1

DS2731: Cache-Memory Battery-Backup Management IC Data Sheet (Rev.1) 01/28/2009

Reliability Data 1

DS2731 Reliability Data 01/12/2023

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
DS2731E+	28-TSSOP_4.4_EP-4.4_MM	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
DS2731E+T&R	28-TSSOP_4.4_EP-4.4_MM	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Mar 9, 2023 - 2276A WAFER FAB
		pcn_2276a
DS2731E+	PRODUCTION
DS2731E+T&R	PRODUCTION
Dec 11, 2018 - 1754N ASSEMBLY
		pcn_1754n
DS2731E+	PRODUCTION
DS2731E+T&R	PRODUCTION
Jan 17, 2018 - 1722E ASSEMBLY
		pcn_1722e
DS2731E+	PRODUCTION
DS2731E+T&R	PRODUCTION

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

Software Resources

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Evaluation Kits

Evaluation Kit for the DS2731

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Features and Benefits

Convenient Power Source and Load Connections
LEDs Indicate Charge Status
Automatic Power-Source Selection
Space for a Wide Variety of Inductor Sizes
Proven, Compact and Low-Cost PCB Layout
Fully Assembled

Product Details

The DS2731 evaluation kit (EV kit) demonstrates all the features of the DS2731 battery-backup power-management IC. The EV kit includes an assembled and tested PCB for easy connection to power sources and a load. Three power sources—a 3.3V auxiliary supply, a 12V supply, and a single lithium-ion (Li+) battery—connect to the DS2731 EV kit to supply the high-efficiency, synchronous buck regulator and battery charger. The IC automatically selects the best-qualified power source for the buck regulator. Thresholds for low-battery voltage, charge regulation voltage and current, charge safety timer, and buck-output voltage are set by resistors.