Li-Ion Battery Charger operates from any wall adapter.
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Press Release Summary:
Model LTC4002 standalone, switch-mode, 1-cell battery charger, with operating supply as high as 24 V, eliminates need for input transient protection. Low 4.7 V input supply and low dropout operation guarantees continuous charging of 4.2 V batteries from 5 V wall adapters. Charger includes automatic shutdown, battery preconditioning, battery temperature sensing, end-of-charge indicator, and 3 hr charge termination timer. Constant operating frequency is 500 kHz.
Original Press Release:
1-Cell Li-Ion Battery Charger with 4.7V to 24V Input Supply Operates from Any Wall Adapter
MILPITAS, CA - August 7, 2003 - Linear Technology Corporation introduces the LTC4002, a standalone switch-mode Li-Ion battery charger with an operating supply as high as 24V, eliminating the need for input transient protection required with 9V and higher wall adapters. Also, low 4.7V input supply and low dropout operation of the IC guarantees continuous charging of 4.2V Li-Ion batteries from 5V wall adapters. For safety and autonomous charge control, the LTC4002 includes features such as automatic shutdown, battery preconditioning, battery temperature sensing, end-of-charge indicator and a 3-hour charge termination timer.
The LTC4002's constant 500kHz operating frequency and current mode architecture allow smaller inductor and capacitors when compared to hysteretic topology chargers. With low 100mV sense voltage, greater than 86% are easily attained. This standalone charger is offered in two packages, the 3mm x 3mm DFN and an 8-lead SO. The LTC4002 has applications in handheld instruments and communication devices, charging docks, portable computers and battery backup systems.
The LTC4002 is a high efficiency current mode PWM controller with 500kHz switching frequency. It drives an external P-channel MOSFET for delivering charge currents as high as 2A with efficiencies as high as 87%. The IC's constant switching frequency minimizes noise and filtering needs. The LTC4002 is stable with all types of output capacitors including low ESR ceramic capacitors. An internal comparator detects the end-of-charge current and an integrated timer sets the total charge time and terminates the charge cycle after 3 hours. The LTC4002 automatically enters sleep mode, dropping the battery drain current to 10uA. Moreover, the IC automatically begins charging when the battery voltage drops below 4.05V.
The LTC4002 is rated from -40°C to 85°C operating temperature. Pricing for the 1,000-quantity starts at $1.95 each.
Summary of Features: LTC4002
Wide Input Supply Range: 4.7V to 24V
High Efficiency Current Mode PWM Controller with 500kHz Switching Frequency
±1% Charge Voltage Accuracy; 5% Charge Current Accuracy
C/10 Charge Current Detection Output
3-Hour Charge Termination Timer
Battery Temperature Sensing and Charge Qualification
Stable with Ceramic Output Capacitors
10-Lead DFN and 8-Lead SO Packages
Company Background
Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. Linear Technology products include operational, instrumentation and audio amplifiers; voltage regulators,power management devices, DC-DC converters and voltage references; comparators; monolithic filters; communications interface circuits; one-chip data acquisition sub-systems; pulse-width modulators and sample-and-hold devices; and high frequency devices. Applications for Linear Technology's high performance circuits include wireless and broadband telecommunications infrastructure, cellular telephones, networking products and satellite systems, notebook and desk top computers, computer peripherals, video/multimedia, industrial and medical instrumentation, automotive electronics, factory automation, process control, military and space systems, and high-end consumer products including digital cameras, MP3 players and other electronic products.
READER SERVICE: Call toll-free 1-800-4-LINEAR (for literature only), or go to the company's web site: www.linear.com
Note: LT, AND LTC are registered trademarks of Linear Technology Corp.
