LTC4040 - 2.5A Battery Backup Power Manager

Features

  • Step-Up Backup Supply and Step-Down Battery Charger
  • 6.5A Switches for 2.5A Backup from 3.2V Battery
  • Input Current Limit Prioritizes Load Over Charge Current
  • Input Disconnect Switch Isolates Input During Backup
  • Automatic Seamless Switch-Over to Backup Mode
  • Input Power Loss Indicator
  • System Power Loss Indicator
  • Pin Selectable Battery: Li-Ion (3.95V/4.0V/4.05V/4.1V) or LiFePO4 (3.45V/3.5V/3.55V/3.6V)
  • Optional OVP Circuitry Protects Device to >60V
  • Constant Frequency Operation
  • Low Profile (0.75mm) 24-Lead 4mm × 5mm QFN Package

Typical Application

LTC4040 Typical Application
LTC4040 Typical Application

Description

The LTC®4040 is a complete 3.5V to 5.5V supply rail battery backup system. It contains a high current step-up DC/DC regulator to back up the supply from a single-cell Li-Ion or LiFePO4 battery. When external power is available, the step-up regulator operates in reverse as a step-down battery charger.

The LTC4040’s adjustable input current limit function reduces charge current to protect the main supply from overload while an external disconnect switch isolates the external supply during backup. When the input supply drops below the adjustable PFI threshold, the 2.5A boost regulator delivers power from the battery to the system output.

An optional input overvoltage protection (OVP) circuit protects the LTC4040 from high voltage damage at the VIN pin. One logic input selects either the Li-Ion or the LiFePO4 battery option, and two other logic inputs program the battery charge voltage to one of four levels suitable for backup applications. The LTC4040 is available in a low profile (0.75mm) 24-Lead 4mm × 5mm QFN package.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

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

Part Number Package Code Temp Package
Drawing
RoHS
LTC4040EUFD#PBF 4x5 QFN-24 UFD E 05-08-1696 Yes
LTC4040EUFD#TRPBF 4x5 QFN-24 UFD E 05-08-1696 Yes
LTC4040IUFD#PBF 4x5 QFN-24 UFD I 05-08-1696 Yes
LTC4040IUFD#TRPBF 4x5 QFN-24 UFD I 05-08-1696 Yes


LTC4040 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

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC4040EUFD#PBF 4x5 QFN-24 E $4.14 $2.90 Yes
LTC4040EUFD#TRPBF 4x5 QFN-24 E $4.20 $2.96 Yes
LTC4040IUFD#PBF 4x5 QFN-24 I $4.71 $3.30 Yes
LTC4040IUFD#TRPBF 4x5 QFN-24 I $3.36 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

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.

Part Number Description Price Documentation
DC2118A LTC4040 Demo Board | 5VIN, 2A Single Cell Li-ion/LiFePO4 Buck Battery Charger with 2.5A Boost Backup Power Manager $150.00
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Click here to view our complete list of demo boards

Applications

  • Fleet and Asset Tracking
  • Automotive GPS Data Loggers
  • Automotive Telematics Systems
  • Toll Collection Systems
  • Security Systems
  • USB Powered Devices

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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!

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