LTC4006

Features:

·Complete Charger Controller for 2-, 3- or 4-Cell Lithium-Ion Batteries
·High Conversion Efficiency: Up to 96%
·Output Currents Exceeding 4A
·±0.8% Accurate Preset Voltages: 8.4V, 12.6V, 16.8V
·Built-In Charge Termination with Automatic Restart
·AC Adapter Current Limiting Maximizes Charge Rate*
·Automatic Conditioning of Deeply Discharged Batteries
·Thermistor Input for Temperature Qualified Charging
·Wide Input Voltage Range: 6V to 28V
·0.5V Dropout Voltage; Maximum Duty Cycle: 98%
·Programmable Charge Current: ±5% Accuracy
·Indicator Outputs for Charging, C/10 Current Detection and AC Adapter Present
·Charging Current Monitor Output
·16-Pin Narrow SSOP Package


Application

·Notebook Computers
·Portable Instruments
·Battery-Backup Systems
·Standalone Li-Ion Chargers


Pinout




Specifications

Voltage from DCIN, CLP, CLN, TGATE, INFET,
ACP/SHDN, CHG to GND .............................. +32V/0.3V
CSP, BAT to GND....................................... ...+28V/0.3V
RT to GND ..................................................... +7V/0.3V
NTC ............................................................. +10V/0.3V
Operating Ambient Temperature Range
(Note 4) .....................................................40 to 85
Operating Junction Temperature ............ 40 to 125
Storage Temperature Range ................... 65 to 150
Lead Temperature (Soldering, 10 sec).................... 300


Description

The LTC®4006 is a complete constant-current/constantvoltage charger controller for 2-, 3- or 4-cell lithium batteries in a small package using few external components.

The PWM controller is a synchronous, quasi-constant frequency, constant off-time architecture that will not generate audible noise even when using ceramic capacitors.

The LTC4006 is available in 8.4V, 12.6V and 16.8V versions with ±0.8% accuracy. Charging current is programmable with a single sense resistor to ±4% typical accuracy. Charging current can be monitored as a representative voltage at the IMON pin. A timer, programmed by an external resistor, sets the total charge time or is reset to 25% of total charge time after C/10 charging current is reached. Charging automatically resumes when cell voltage falls below 3.9V/cell.

Fully discharged cells are automatically trickle charged at 10% of the programmed current until the cell voltage exceeds 2.5V/cell. Charging terminates if the low-battery condition persists for more than 25% of the total charge time.

LTC4006 includes a thermistor sensor input that suspends charging if an unsafe temperature condition is detected and automatically resumes charging when battery temperature returns to within safe limits.