LTC4007

· Complete Charger Controller for 3- or 4-Cell Lithium-Ion Batteries
· High Conversion Efficiency: Up to 96%
· Output Currents Exceeding 4A
· ±0.8% Charging Voltage Accuracy
· Built-In Charge Termination for Li-Ion Batteries
· AC Adapter Current Limiting Maximizes Charge Rate*
· 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, AC Adapter Present, Low Battery, Input Current Limiting and Faults
· Charging Current Monitor Output
· Available in a 24-Pin Narrow SSOP Package

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

Voltage from DCIN, CLP, CLN to GND ....... +32V/0.3V
PGND with Respect to GND ................................ ±0.3V
CSP, BAT to GND....................................... +28V/0.3V
CHEM, 3C4C, R_T to GND ............................. +7V/0.3V
NTC .......................................................... +10V/0.3V
ACP, SHDN, CHG, FLAG,
FAULT, LOBAT, ICL ................................... + 32V/0.3V
Operating Ambient Temperature Range
(Note 4) ............................................. 40°C to 85°C
Operating Junction Temperature .... 40°C to 125°C
Storage Temperature Range ........... 65°C to 150°C
Lead Temperature (Soldering, 10 sec)............... 300°C

The LTC^®4007 is a complete constant-current/constantvoltage charger controller for 3- or 4-cell lithium-ion batteries. The PWM controller uses a synchronous, quasiconstant frequency, constant off-time architecture that will not generate audible noise even when using ceramic capacitors. Charging current is programmable to ±5% accuracy using a programming resistor. Charging current can also be monitored as a voltage across the programming resistor.

The output float voltage of LTC4007 is pin programmed for cell count (3 cells or 4 cells) and chemistry (4.2V/4.1V). A timer, programmed by an external resistor, sets the total charge time. Charging is automatically restarted when cell voltage falls below 3.9V/cell

LTC4007 includes a thermistor input, which suspends charging if an unsafe temperature condition is detected. If the cell voltage is less than 2.5V, a low-battery indicator asserts and can be used to program a trickle charge current to safely charge depleted batteries. The FAULT pin is also asserted and charging terminates if the low-battery condition persists for more than 1/4 of the total charge time.