Power Management Battery Management Coulomb Counter (Battery Fuel Gauge)

Obsolete

For New Designs

LTC4110 - Battery Backup System Manager

LT1239 - Backup Battery Management Circuit

Features

  • Obsolete - Datasheet For Information Purposes Only.  Contact Linear Technology for Potential Replacement
  • Micropower Operation (IQ = 20µA)
  • Adjustable Regulator for Battery Charging
  •  4.85V Regulator for Battery Regulation
  • Cell Voltage Equalization in 2-Cell Systems
  • Low-Battery Detector Protects Lithium Cells
  • Comparator for Automatic Power Switching
  • Shutdown
  • Output Current Sensing
  • Current and Thermal Limiting

Typical Application

LT1239 Typical Application

Description

Obsolete - Datasheet For Information Purposes Only.  Contact Linear Technology for Potential Replacement

The LT1239 is a micropower backup battery management system for portable computers and instrumentation. It contains two regulators for regulating the battery voltage and memory voltage and a comparator for switching between main power and backup power. The first regulator provides a constant voltage charge for the backup batteries and is adjustable from 3.75V up to 20V. An equalization amplifier combined with the first regulator provides precision charge equalization for a 2-cell lithium-ion system. A second regulator with 4.85V output provides aregulated backup battery voltage to the memory when main power is lost. The second regulator also isolates the backup battery from the main 5V supply during normal operation when the memory is being powered by the 5V supply.

A comparator is included which provides automatic switchover from main 5V power to backup power ensuring uninterrupted power for memory and power monitoring circuitry. A low-battery detector with a 5V threshold powers down the second regulator and the error amplifier to limit the discharge voltage of the backup cells. This prevents deep discharge damage to the lithium cells. Both regulators have independent shutdown and current monitor functions.

Packaging

For complete and up to date package information and drawings, please refer to our packaging page

LT1239 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Click here to view our complete list of demo boards

Applications

  • Backup Battery Management Systems for Portable Computers
  • Lithium-Ion Backup Systems
  • NiCd Backup Systems

People Who Viewed This Product Also Viewed

Product Notifications

Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.

Forgot your password? Click here.
Need help? Email mylinear@linear.com with questions and comments.

Design Tools

Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:

  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
  • LTpowerCAD - A complete power supply selection, synthesis and design tool
  • LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
  • PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
  • Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
  • LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
  • And More!

Technical Support