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DS2731
Cache-Memory Battery-Backup Management IC

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


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Status
Active: In Production.

Data Sheet
FULL DATA SHEET (PDF, 216kB)
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Description
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.

An evaluation kit is available:  DS2731EVKIT  

Key Features   Applications/Uses
  • 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

 
  • RAID Server Memory Card

    Key Specifications:  Battery Chargers
    Part Number Cell Chemistry Lithium Ion Cells Protected VIN
    (V)
    Charging VIN
    (V)
    Charge Rate Set by Max. ICHG
    (A)
    Charge Termination Charge Regulation Features Package/Pins Smallest Available Pckg.
    (mm2)
    Oper. Temp.
    (°C)
    Price
    max max max w/pins See Notes
    DS2731 
    Li-Ion
    Li-Polymer
    1 13.2 13.2 Resistor 1.5 Min. Charge Current Switchmode
    Adjustable Reset Input
    Internal FET/Transistor
    Stand Alone
    Thermal Die Regulation
    Thermistor Input
    Timer
    TSSOP-EP/28
    64 -20 to +70 $4.81 @1k
    See All Battery Chargers (62)

    Key Specifications:  Battery Backup Circuits
    Part Number Reset Thresh.
    (V)
    ICC
    (µA)
    Features Package/Pins Smallest Available Pckg.
    (mm2)
    Oper. Temp.
    (°C)
    Price
    max max w/pins See Notes
    DS2731  2.5 to 3.3 150
    Adjustable Reset Input
    Internal FET/Transistor
    Stand Alone
    Thermal Die Regulation
    Thermistor Input
    Timer
    TSSOP-EP/28
    64 -20 to +70 $4.81 @1k
    See All Battery Backup Circuits (86)

    Diagram
    DS2731: Typical Operating Circuit
    Typical Operating Circuit

    Evaluation Kits
  • DS2731EVKIT

    Design Guides
  • Battery Management (PDF)
  • Power Management for Battery-Powered Equipment (PDF)

    Reliability Reports
  • Reliability Report: DS2731.pdf

    Software/Models
    none

    Ordering Information
    Notes:

    1. Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
    2. Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
    3. Part number suffixes: T or T&R = tape and reel;+ = RoHS/lead-free;# = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions.
    4. * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.


    Devices: 1-2 of 2

    DS2731 Free
    Sample
    Buy Status
    Package: TYPE PINS FOOTPRINT
      DRAWING CODE/VAR *
    Temp RoHS/Lead-Free?
    Materials Analysis
    DS2731E+  
    Active TSSOP-EP;28 pin;64 mm²
    Outline Drawing: 21-0108 (PDF)
    Land Pattern: 90-0146 (PDF)
    Use pkgcode/variation: U28E+4*
    -40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    DS2731E+T&R    
    Active TSSOP-EP;28 pin;64 mm²
    Outline Drawing: 21-0108 (PDF)
    Land Pattern: 90-0146 (PDF)
    Use pkgcode/variation: U28E+4*
    -40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis

    More Information
  • New Product Press Release 2008-06-25 

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     Description 
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     Diagram 

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    2009-01-28
    This page last modified: 2009-09-01


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