LTC4040

2.5A Battery Backup Power Manager

Data Sheet

Recommended for New Designs

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Alternative Parts

LTC4110

Battery Backup System Manager

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Overview

Features and Benefits
Product Details

Features and Benefits

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

Product Details

The LTC4040 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 V_IN 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.

Applications

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

Product Categories

Power Management
- Switching Battery Chargers
- Battery Backup IC

Markets & Technology

Automotive
- Telematics

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Product Lifecycle Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Evaluation Kits (2)

DC2118B

LTC4040 Demo Board | 5V_IN, 2A Single Cell Li-ion/LiFePO₄ Buck Battery Charger with 2.5A Boost Backup Power Manager

DC2118A

OBSOLETE: LTC4040 Demo Board | 5V_IN, 2A Single Cell Li-ion/LiFePO4 Buck Battery Charger with 2.5A Boost Backup Power Manager

DC2118B

View Detailed Evaluation Kit Information

Demonstration circuit 2118B is a combination step-down battery charger and step-up battery backup regulator using the LTC4040 monolithic system power manager. The DC2118B has an input voltage range from 4.8V to 5.5V with overvoltage protection (OVP) to 40V, as limited by the external MOSFET. The input current is monitored to prioritize the load up to the 2.5A threshold before charge current is reduced.

Battery Charging

As initially configured, DC2118B is programmed for 2A charge current limit when in charge mode. The charge voltage is jumper-selectable in 8 discrete steps from 3.45V to 3.6V for LiFePO₄ chemistry or 3.95V to 4.1V for Li-ion chemistry, according to the F2/F1/F0 programming input settings.

The charge current limit is adjustable via the PROG pin resistor. End-of-charge status is triggered by current falling below C/8 and indicated by the CHRG LED. The optional NTC input provides temperature fault detection and status indicated by the FAULT LED. Charging can be enabled/disabled with the ENCHG jumper.

Battery Backup

Following an input power failure, the circuit automatically shifts to battery backup boost mode to regulate the VSYS output rail. The backup mode system output voltage is initially programmed for 5V. The input power failure status is indicated by the PFO LED.

If VSYS ever falls below the programmed reset threshold voltage, the RST LED will change states to indicate the need to reset the system and recharge the battery. Backup regulation can be enabled/disabled with the ENBST jumper.

For convenience, all LEDs can be disabled with the LED jumper to reduce the quiescent current of the system.

Resources

DC2118A

View Detailed Evaluation Kit Information

This evaluation board is obsolete and no longer recommended.

Demonstration circuit 2118A is a combination step-down battery charger and step-up battery backup regulator using the LTC4040 monolithic system power manager. The DC2118A has an input voltage range from 4.8V to 5.5V with overvoltage protection (OVP) to 40V, as limited by the external MOSFET. The input current is monitored to prioritize the load up to the 2.5A threshold before charge current is reduced.

Resources

Documentation

Data Sheets (1)

PDF

1.00M

LTC4040: 2.5A Battery Backup Power Manager Data Sheet

Reliability Data (1)

PDF

65.93 K

R457 Reliability Data

Application Notes (1)

PDF

514.82 K

AN-171: Reverse Voltage Protection for Battery Chargers (Rev. 0)

Evaluation Kit Manuals (2)

PDF

612.3 K

DC2118B - Demo Manual

PDF

348.00K

DC2118A - Demo Manual

Product Recommendations

LTC4040 Companion Parts

Recommended Related Parts

LTC4231, LTC4417.

Reference Materials

Product Selector Card (1)

Backup Power Solutions

Technical Articles (1)

Got Backup? Maintain Power Continuity

Design Resources

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.

Quality And Reliability

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Support & Discussions

LTC4040 Discussions

RE: LTC4040 LiFePO4 battery charging profile

4 week(s) ago in Power By Linear

LTC4040EUFD vs. LTC4040IUFD part numbering

11 week(s) ago in Power By Linear

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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.

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