LTC4156 - Dual-Input Power Manager/ 3.5A LiFePO4 Battery Charger with I2C Control and USB OTG


  • High Efficiency Charger Capable of 3.5A Charge Current
  • Charge Control Algorithm Specifically Designed for LiFePO4 Batteries (Lithium Iron Phosphate)
  • Monolithic Switching Regulator Makes Optimal Use of Limited Power and Thermal Budget
  • Dual Input Overvoltage Protection Controller
  • Priority Multiplexing for Multiple Inputs
  • I2C/SMBus Control and Status Feedback
  • NTC Thermistor ADC for Temperature Dependent Charge Algorithms (JEITA)
  • Instant-On Operation with Low Battery
  • Battery Ideal Diode Controller for Power Management
  • USB On-The-Go Power Delivery to the USB Port
  • Four Float Voltage Settings (3.45V, 3.55V, 3.6V, 3.8V)
  • 28-Lead 4mm × 5mm QFN Package

Typical Application

LTC4156 Typical Application
LTC4156 Typical Application


The LTC®4156 is a 15 watt I2C controlled power manager with PowerPath™ instant-on operation, high efficiency switching battery charging and USB compatibility. The LTC4156 seamlessly manages power distribution from two 5V sources, such as a USB port and a wall adapter, to a single-cell rechargeable lithium iron phosphate battery and a system load.

The LTC4156’s switching battery charger automatically limits its input current for USB compatibility, or may draw up to 3A from a high power wall adapter. The high efficiency step-down switching charger is designed to provide maximum power to the application and reduced heat in high power density applications.

I2C adjustability of input current, charge current, battery float voltage, charge termination, and many other parameters allows maximum flexibility. I2C status reporting of key system and charge parameters facilitates intelligent control decisions. USB On-The-Go support provides 5V power back to the USB port without any additional components. A dual-input, priority multiplexing, overvoltage protection circuit guards the LTC4156 from high voltage damage on the VBUS pin.

The LTC4156 is available in the low profile (0.75mm) 28-lead 4mm × 5mm QFN surface mount package.


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
LTC4156EUFD#PBF 4x5 QFN-28 UFD E 05-08-1712 Yes
LTC4156EUFD#TRPBF 4x5 QFN-28 UFD E 05-08-1712 Yes
LTC4156IUFD#PBF 4x5 QFN-28 UFD I 05-08-1712 Yes
LTC4156IUFD#TRPBF 4x5 QFN-28 UFD I 05-08-1712 Yes

LTC4156 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
LTC4156EUFD#PBF 4x5 QFN-28 E $4.22 $2.95 Yes
LTC4156EUFD#TRPBF 4x5 QFN-28 E $3.01 Yes
LTC4156IUFD#PBF 4x5 QFN-28 I $4.64 $3.25 Yes
LTC4156IUFD#TRPBF 4x5 QFN-28 I $3.31 Yes
Buy NowRequest Samples
* 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
DC1674A-B LTC4156EUFD Demo Board | Dual Input Power Mgr/3.5A LiFePO4 Charger, VIN = 4.35V to 5.5V, VOUT = 4.5V @ 3.5A; DC590B Demo Board is required $150.00
Buy Now

Companion Boards

Part Number Description Price Documentation
DC590B Isolated USB Serial Controller for Linear Technology QuikEval-Compatible Demo Boards $50.00
Buy Now
Click here to view our complete list of demo boards


  • Portable Medical Devices
  • Portable Industrial Devices
  • Backup Devices

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 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