Overview

Features and Benefits

  • Charges Single-Cell Li-Ion Battery from Wall Adapter and USB Inputs
  • Automatic Input Power Detection and Selection
  • Charge Current Programmable Up to 950mA from Wall Adapter Input
  • Adjustable Output, High Efficiency 600mA Synchronous DC/DC Converter
  • No External MOSFET, Sense Resistor or Blocking Diode Needed
  • Thermal Regulation Maximizes Charge Rate Without Risk of Overheating*
  • Preset Charge Voltage with ±0.6% Accuracy
  • Programmable Charge Current Termination
  • 1.5MHz Constant Frequency Operation (Step-Down Converter)
  • 18μA USB Suspend Current in Shutdown
  • “Power Present” Status Output
  • Charge Status Output
  • Automatic Recharge
  • Available in a Thermally Enhanced, Low Profile (0.75mm) 16-Lead (5mm × 3mm) DFN Package

Product Details

The LTC3550 is a standalone linear charger with a 600mA monolithic synchronous buck converter. It is capable of charging a single-cell Li-Ion battery from both wall adapter and USB inputs. The charger automatically selects the appropriate power source for charging.

Internal thermal feedback regulates the battery charge current to maintain a constant die temperature during high power operation or high ambient temperature conditions. The float voltage is fixed at 4.2V and the charge currents are programmed with external resistors. The LTC3550 terminates the charge cycle when the charge current drops below the programmed termination threshold after the final float voltage is reached. With power applied to both inputs, the LTC3550 can be put into shutdown mode reducing the DCIN supply current to 20μA, the USBIN supply current to 10μA, and the battery drain current to less than 2μA.

The DC/DC converter switching frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and capacitors.


Vout
LTC3550 Adjustable
LTC3550-1 1.875V

Applications

  • Cellular Telephones

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Evaluation Kits (1)

Tools & Simulations

LTspice

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

LTspice

Models for the following parts are available in LTspice:

LTC3550
LTC3550-1

Product Recommendations

LTC3550 Companion Parts

Recommended Related Parts

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.

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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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


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Evaluation Boards Pricing displayed is based on 1-piece.
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.