LTC4085 - USB Power Manager with Ideal Diode Controller and Li-Ion Charger

Features

  • Seamless Transition Between Input Power Sources: Li-Ion Battery, USB and 5V Wall Adapter
  • 215mΩ Internal Ideal Diode Plus Optional External Ideal Diode Controller Provide Low Loss PowerPathTM When Wall Adapter/USB Input Not Present
  • Load Dependent Charging Guarantees Accurate USB Input Current Compliance
  • 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
  • Preset 4.2V Charge Voltage with 0.8% Accuracy
  • C/10 Charge Current Detection Output
  • NTC Thermistor Input for Temperature Qualified Charging
  • Tiny (4mm × 3mm × 0.75mm) 14-Lead DFN Package

Typical Application

LTC4085 Typical Application
LTC4085 Typical Application

Description

The LTC4085 is a USB power manager and Li-Ion 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 includes a complete constant-current/constant- voltage linear charger for single cell Li-ion batteries. The float voltage applied to the battery is held to a tight 0.8% tolerance, and charge current is programmable using an external resistor to ground. An end-of-charge status output CHRG indicates full charge. Total charge time is programmable by an external capacitor to ground. When the battery drops 100mV below the float voltage, automatic recharging of the battery occurs. Also featured is an NTC thermistor input used to monitor battery temperature while charging.

The LTC4085 is available in a 14-lead low profile 4mm × 3mm DFN package.

 Float Voltage (V)NTC Hot ThresholdUndervoltage 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

Packaging

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
Drawing
RoHS
LTC4085EDE#PBF 4x3 DFN-14 DE E 05-08-1708 Yes
LTC4085EDE#TRPBF 4x3 DFN-14 DE E 05-08-1708 Yes


LTC4085 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
(1-99)
Price
(1k)*
RoHS
LTC4085EDE#PBF 4x3 DFN-14 E $2.36 $1.65 Yes
LTC4085EDE#TRPBF 4x3 DFN-14 E $1.71 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
DC937A LTC4085EDE Demo Board | 700mA CC/CV Li-Ion Linear Charger, VIN = 4.5V to 5.5V $150.00
Buy Now
Click here to view our complete list of demo boards

Applications

  • Portable USB Devices: Cameras, MP3 Players, PDAs

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

Models for the following parts are available in LTspice:
LTC4085
LTC4085-1
LTC4085-3
LTC4085-4

Technical Support