LTC3558 - Linear USB Battery Charger with Buck and Buck-Boost Regulators


    Battery Charger
  • Standalone USB Charger
  • Up to 950mA Charge Current Programmable via
  • Single Resistor
  • HPWR Input Selects 20% or 100% of Programmed Charge Current
  • NTC Input for Temperature Qualified Charging
  • Internal Timer Termination
  • Bad Battery Detection
    Switching Regulators (Buck and Buck-Boost)
  • Up to 400mA Output Current per Regulator
  • 2.25MHz Constant-Frequency Operation
  • Power Saving Burst Mode Operation
  • Low Profile, 20-Lead, 3mm × 3mm QFN Package

Typical Application

LTC3558 Typical Application
LTC3558 Typical Application


The LTC3558 is a USB battery charger with dual high efficiency switching regulators. The device is ideally suited to power single-cell Li-Ion/Polymer based handheld applications needing multiple supply rails.

Battery charge current is programmed via the PROG pin and the HPWR pin with capability up to 950mA of current at the BAT pin. The CHRG pin allows battery status to be monitored continuously during the charging process. An internal timer controls charger termination.

The part includes monolithic synchronous buck and buck-boost regulators that can provide up to 400mA of output current each and operate at efficiencies greater than 90% over the entire Li-Ion/Polymer battery range. The buck- boost regulator can regulate its programmed output voltage at its rated deliverable current over the entire Li-Ion range without drop out, increasing battery runtime.

The LTC3558 is offered in a low profile (0.75mm), thermally enhanced, 20-lead (3mm × 3mm) QFN 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
LTC3558EUD#PBF 3x3 QFN-20 UD E 05-08-1720 Yes
LTC3558EUD#TRPBF 3x3 QFN-20 UD E 05-08-1720 Yes

LTC3558 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
LTC3558EUD#PBF 3x3 QFN-20 E $3.43 $2.40 Yes
LTC3558EUD#TRPBF 3x3 QFN-20 E $2.46 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
DC1276B LTC3558EUD | Linear USB Battery Charger with Buck and Buck-Boost Regulators $200.00
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Click here to view our complete list of demo boards


  • SD/Flash-Based MP3 Players
  • Low Power Handheld Applications

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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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