반도체 전문 온라인 매거진 - 올포칩

Linear Technology Corporation introduces the LTC4059, a tiny single-cell Li-Ion linear charger that eliminates the need for three discrete power components, fast charges without any risk of system overheating, monitors and reports the value of the charge current and is offered in the smallest possible package without compromising thermal performance. The complete solution requires only two discrete components (input capacitor and charge current program resistor) and fits in a 2.5mm x 2.7mm footprint. The LTC4059s 2mm x 2mm DFN package has less than half the footprint of a SOT-23 package and offers up to 60°C/W lower thermal resistance for improved heat dissipation. With proper PCB layout design, the LTC4059 can safely charge a single-cell, Li-Ion battery from 5V input at up to 900mA. Moreover, it is not necessary to design for worst-case power dissipation scenarios since the LTC4059s patented thermal regulation scheme automatically reduces charge current as necessary during high ambient temperature conditions to maintain thermal control. Applications include digital still cameras, and portable POS and diagnostic equipment as well as cell phones, PDAs and USB-equipped handheld devices. The LTC4059 requires no external MOSFET, current sense resistor or reverse current blocking diode. Charge current is adjustable with an off-the-shelf standard resistor. The LTC4059 operates from input supplies ranging from 3.75V to 8V including USB ports. During shutdown, the supply current is only 10uA and battery drain current is less than 1uA. A charge current monitor pin produces a voltage that is proportional to the charge current. A microprocessor can use this voltage for charge termination and control. In addition, the LTC4059 can be configured as a constant-current source for charging NiMH/NiCd batteries. The LTC4059 is rated for operation from -40°C to 85°C. 1,000-piece pricing starts at $1.35 each.