Overview

Features and Benefits

  • Seamless Transition Between Input Power Sources: Li-Ion/Polymer Battery, USB and 5V Wall Adapter
  • 215mΩ Internal Ideal Diode Plus Optional External Ideal Diode Controller Provide Low Loss PowerPath When Wall Adapter/USB Input Not Present
  • Load Dependent Charging Guarantees Accurate USB Input Current Compliance
  • 3.95V Float Voltage Improves Battery Life Span and High Temperature Safety Margin
  • Constant-Current/Constant-Voltage Operation with Thermal Feedback to Maximize Charging Rate without Risk of Overheating*
  • Selectable 100% or 20% Input Current Limit (e.g., 500mA/100mA)
  • Battery Charge Current Independently Programmable Up to 1.2A
  • Automatic Output Undervoltage Charge Current Reduction (LTC4085-3)
  • Tiny (4mm × 3mm × 0.75mm) 14-Lead DFN Package

Product Details

The LTC4085-3/LTC4085-4 is a USB power manager and Li-Ion/Polymer battery charger designed for portable battery-powered applications. The part controls the total current used by the USB peripheral for operation and battery charging. The total input current can be limited to 20% or 100% of a programmed value up to 1.5A (typically 100mA or 500mA). Battery charge current is automatically reduced such that the sum of the load current and charge current does not exceed the programmed input current limit.

The LTC4085-3/LTC4085-4 includes a complete constantcurrent/ constant-voltage linear charger for single cell Li-Ion batteries. These 3.95V versions of the standard LTC4085 are intended for applications which have extended battery lifetime requirements or those that require high temperature (approximately >60°C) operation or storage. Under these conditions, a reduced fl oat voltage will trade-off initial cell capacity for the benefi t of increased capacity retention over the life of the battery. A reduced fl oat voltage also minimizes swelling in prismatic and polymer cells, and avoids open CID (pressure fuse) in cylindrical cells.

The LTC4085-3/LTC4085-4 also includes a programmable termination timer, automatic recharging, an end-of-charge status output and an NTC thermistor.

Float Voltage (V) NTC Hot Threshold Undervoltage Current Limit
LTC4085 4.2V 29% Vvntc Yes
LTC4085-1 4.1V 32.6% Vvntc Yes
LTC4085-3 3.95V 32.6% Vvntc Yes
LTC4085-4 3.95V 32.6% Vvntc No

Applications

  • Portable USB Devices
No

Product Lifecycle icon-recommended 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.

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:

LTC4085
LTC4085-1
LTC4085-3
LTC4085-4

Product Recommendations

LTC4085-3 Companion Parts

Recommended µModule Isolator

Reference Materials

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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