LTC4059/LTC4059A - 900mA Linear Li-Ion Battery Chargers with Thermal Regulation in 2 × 2 DFN


  • Programmable Charge Current Up to 900mA
  • Charge Current Monitor Output for Charge Termination
  • Constant-Current/Constant-Voltage Operation with Thermal Regulation to Maximize Charging Rate Without Risk of Overheating
  • Constant-Current Source Mode for Charging Nickel Batteries (LTC4059 Only)
  • ACPR Pin Indicates Presence of Input Supply (LTC4059A Only)
  • No External MOSFET, Sense Resistor or Blocking Diode Required
  • Operating Supply Voltage from 3.75V to 8V
  • Charges Single Cell Li-Ion Batteries Directly from USB Port
  • Preset 4.2V Charge Voltage with 0.6% Accuracy
  • 10μA Supply Current in Shutdown Mode
  • Tiny 6-Lead (2mm × 2mm) DFN Package

Typical Application

LTC4059 Typical Application
LTC4059 Typical Application


The LTC®4059/LTC4059A are constant-current/constant-voltage linear chargers for single cell lithium-ion batteries. Their 2mm × 2mm DFN package and low external component count make these chargers especially well suited for portable applications. Furthermore, they are designed to work within USB power specifications.

No external sense resistor, MOSFET or blocking diode is required. Thermal feedback regulates the charge current to limit the die temperature during high power operation or high ambient thermal conditions. The charge voltage is fixed at 4.2V and the charge current is programmable.

When the input supply (wall adapter or USB supply) is removed, the LTC4059/LTC4059A automatically enter a low current state, dropping the battery current drain to less than 1μA. With power applied, they can be put into shutdown mode, reducing the supply current to 10μA.

The LTC4059A features an open-drain status pin to indicate the presence of an input voltage. The LTC4059 can be used as a constant-current source to charge Nickel cells. Other features include undervoltage lockout protection and a current monitor pin which can indicate when to terminate a charge cycle.

The LTC4059/LTC4059A are available in a 6-lead, low profile (0.75mm) 2mm × 2mm DFN 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
LTC4059AEDC#PBF 2x2 DFN-6 DC6 E 05-08-1703 Yes
LTC4059AEDC#TRMPBF 2x2 DFN-6 DC6 E 05-08-1703 Yes
LTC4059AEDC#TRPBF 2x2 DFN-6 DC6 E 05-08-1703 Yes
LTC4059EDC#PBF 2x2 DFN-6 DC6 E 05-08-1703 Yes
LTC4059EDC#TRMPBF 2x2 DFN-6 DC6 E 05-08-1703 Yes
LTC4059EDC#TRPBF 2x2 DFN-6 DC6 E 05-08-1703 Yes

LTC4059 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
LTC4059AEDC#PBF 2x2 DFN-6 E $2.37 Yes
LTC4059AEDC#TRMPBF 2x2 DFN-6 E $2.37 $1.57 Yes
LTC4059AEDC#TRPBF 2x2 DFN-6 E $2.37 $1.55 Yes
LTC4059EDC#PBF 2x2 DFN-6 E $2.19 Yes
LTC4059EDC#TRMPBF 2x2 DFN-6 E $2.19 $1.47 Yes
LTC4059EDC#TRPBF 2x2 DFN-6 E $2.19 $1.45 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
DC685A LTC4059EDC | 750mA Linear Battery Charger, +Vin = 3.8V to 6.3V, Iout (Max) = 750mA $75.00
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