LT1505 - Constant-Current/Voltage High Efficiency Battery Charger

A third control loop limits the current drawn from the AC adapter during charging*. This allows simultaneous operation of the equipment and fast battery charging without overloading the AC adapter.

The LT1505 can charge batteries ranging from 2.5V to 20V with dropout voltage as low as 0.5V. Synchronous N-channel FETs switching at 200kHz give high efficiency and allow small inductor size. A diode is not required in series with the battery because the charger automatically enters a 10µA sleep mode when the wall adapter is unplugged. A logic output indicates Li-Ion full charge when current drops to 20% of the programmed value.

The LT1505 is available in a 28-pin SSOP package.

Features
  • Simple Charging of Li-Ion, NiMH and NiCd Batteries
  • Very High Efficiency: Up to 97%
  • Precision 0.5% Charging Voltage Accuracy
  • Preset Battery Voltages: 12.3V, 12.6V, 16.4V and 16.8V
  • 5% Charging Current Accuracy
  • Charging Current Programmed by Resistor or DAC
  • 0.5V Dropout Voltage, Duty Cycle > 99.5%
  • AC Adapter Current Limit* Maximizes Charging Rate
  • Flag Indicates Li-Ion Charge Completion
  • Auto Shutdown with Adapter Removal
  • Only 10µA Battery Drain When Idle
  • Synchronizable Up to 280kHz
Typical Application
Applications
  • Notebook Computers
  • Portable Instruments
  • Chargers for Li-Ion, NiMH, NiCd and Lead Acid Rechargeable Batteries
Packaging

Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT1505CG-1#PBFSSOP-28C$5.15$4.60
LT1505CG-1#TRPBFSSOP-28C$4.70
LT1505CG#PBFSSOP-28C$5.65$4.80
LT1505CG#TRPBFSSOP-28C$4.90
Demo Boards
Part NumberDescriptionPrice
DC219ALT1505CG | 4A CC-CV Lithium-Ion Battery Charger, Vin max < 24V, Vin min = Vbat +0.5V (thru-hole caps)Contact Factory
Datasheet
Design Note
Reliability Data
LT Journal
Related Product
LT1505 - Constant-Current/Voltage High Efficiency Battery Charger
LT1505 Package Drawing LT1505
DN242 - Li-Ion Charge Termination IC Interfaces with PWM Switchers
DN244 - Simple Li-Ion Charge Termination Using the LT1505
R324 Reliability Data
Feb 1999 Fast Rate Li-Ion Battery Charger
LT1505 Footprints and Symbols