LTC4008 - 4A, High Efficiency, Multi-Chemistry Battery Charger


  • General Purpose Charger Controller
  • High Conversion Efficiency: Up to 96%
  • Output Currents Exceeding 4A
  • ±0.8% Voltage Accuracy
  • AC Adapter Current Limiting Maximizes Charge Rate*
  • Thermistor Input for Temperature Qualified Charging
  • Wide Input Voltage Range: 6V to 28V
  • Wide Output Voltage: 3V to 28V
  • 0.5V Dropout Voltage; Maximum Duty Cycle: 98%
  • Programmable Charge Current: ±4% Accuracy
  • Indicator Outputs for Charging, C/10 Current
    Detection, AC Adapter Present, Input Current
    Limiting and Faults
  • Charging Current Monitor Output
  • Available in a 20-Pin Narrow SSOP Package

Typical Application

LTC4008 Typical Application


The LTC4008 is a constant-current/constant-voltage charger controller. The PWM controller uses a synchronous, quasi-constant frequency, constant off-time architecture that will not generate audible noise even when using ceramic capacitors. Charging current is programmable with a sense resistor and programming resistor to ±4% typical accuracy. Charging current can be monitored as a voltage across the programming resistor. An external resistor divider and precision internal reference set the final float voltage.

The LTC4008 includes a thermistor sensor input that will suspend charging if an unsafe temperature condition is detected and will automatically resume charging when battery temperature returns to within safe limits; a FAULT pin indicates this condition. A FLAG pin indicates when charging current has decreased below 10% of the programmed current. An external sense resistor programs AC adapter current limiting. The ICL pin indicates when the charging current is being reduced by input current limiting so that the charging algorithm can adapt.


For complete and up to date package information and drawings, please refer to our packaging page


LTC4008 Package Drawing
LTC4008 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LTC4008EGN SSOP 20 E $5.27 $3.70 View
LTC4008EGN#PBF SSOP 20 E $5.27 $3.70 View
LTC4008EGN#TR SSOP 20 E $3.80 View
LTC4008EGN#TRPBF SSOP 20 E $3.80 View
LTC4008EGN-1 SSOP 20 E $5.27 $3.70 View
LTC4008EGN-1#PBF SSOP 20 E $5.27 $3.70 View
LTC4008EGN-1#TR SSOP 20 E $3.80 View
LTC4008EGN-1#TRPBF SSOP 20 E $3.80 View
Buy NowRequest Samples
* 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.

Click here to view our complete list of demo boards


  • Notebook Computers
  • Portable Instruments
  • Battery Backup Systems

Product Notifications

Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.

Forgot your password? Click here.
Need help? Email with questions and comments.

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:

Technical Support