LTC4099 - I2C Controlled USB Power Manager/Charger with Overvoltage Protection


  • Switching Regulator with Bat-Track™ Adaptive Output Control Makes Optimal Use of Limited Input Power
  • I2C Port for Optimal System Performance and Status Information
  • Input Overvoltage Protection
  • Bat-Track Control of External Step-Down Switching Regulator Maximizes Efficiency from Automotive and Other High Voltage Sources
  • Instant-On Operation with Low Battery
  • Optional Overtemperature Battery Conditioner Improves High Temperature Battery Safety Margin
  • Ideal Diode Seamlessly Connects Battery When Input Power is Limited or Unavailable
  • Full-Featured Li-Ion/Polymer Battery Charger
  • 1.5A Maximum Charge Current with Thermal Limiting
  • Slew Control Reduces Switching EMI
  • 20-Lead 3mm × 4mm × 0.75mm QFN Package

Typical Application

LTC4099 Typical Application
LTC4099 Typical Application


The LTC4099 is an I2C controlled high efficiency USB PowerPath controller and full-featured Li-Ion/Polymer battery charger. It seamlessly manages power distribution from multiple sources including USB, a wall adapter and a Li-Ion/Polymer battery.

The LTC4099 automatically limits its input current for USB compatibility. For automotive and other high voltage applications, the LTC4099 interfaces with an external switching regulator. Both the USB input and the auxiliary input controller feature Bat-Track optimized charging to provide maximum power to the application and reduced heat in high power density applications.

The I2C port allows digital control of important application parameters including input current limit, charge current and float voltage. Several status bits can also be read back via I2C.

An overvoltage protection circuit guards the LTC4099from high voltage damage on the low voltage VBUS pin.TheLTC4099 is available in a 20-Lead 3mm × 4mm × 0.75mmQFN 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
LTC4099EUDC#PBF 3x4 QFN-20 UDC E 05-08-1742 Yes
LTC4099EUDC#TRPBF 3x4 QFN-20 UDC E 05-08-1742 Yes

LTC4099 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
LTC4099EUDC#PBF 3x4 QFN-20 E $3.14 $2.20 Yes
LTC4099EUDC#TRPBF 3x4 QFN-20 E $2.26 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
DC1396A LTC4099EPDC Demo Board | I2C-Controlled USB Power Manager/Charger with Overvoltage Protection (req. DC590) $150.00
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Companion Boards

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


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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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