EMC4054概述
EMC5040完整的单节锂离子电池用恒定电流/恒定电压线性充电器。其TDFN-10封装与较少的外部组件数目使得EMC5040成为便携式应用的理想选择。而且，EMC5040是专为在 USB 电源规范内工作而设计的。采用了内部 MOSFET 架构，所以不需要外部检测电阻器和隔离二极管。热反馈可对充电电流进行调节，以便在大功率操作或高环境温度条件下对芯片温度加以限制。充电电压固定于 4.2V，而充电电流可通过一个电阻器进行外部设置。当充电电流在达到最终浮充电压之后降至设定值的 1/10 时，EMC5040 将自动终止充电循环。当输入电压 (交流适配器或 USB 电源) 被拿掉时，EMC5040自动进入一个低电流状态，将电池漏电流降至 2µA 以下。可将EMC5040置于停机模式，从而将供电电流降至 25µA。
The EMC5040 is a complete linear charger for single cell lithium-ion batteries. With small TDFN-10 package and few external components, EMC5040 is well suited for portable applications. In addition, the EMC5040 is specifically designed to work within USB power specifications.  No external sense resistor and blocking diode are required. Charging current can be programmed externally with a single resistor. The built-in thermal regulation facilitates charging with maximum power without risk of overheating. 
The EMC5040 always preconditions the battery with 1/10 of the programmed charge current at the beginning of a charge cycle, after it verifies that the battery can be fast-charged. The EMC5040 automatically terminates the charge cycle when the charge current drops to 1/10th the programmed value after the final float voltage is reached. 
The EMC5040 features 13.5V maximum rating voltage for AC adapter, and it provides the charge current up to 1.2A. Other features include battery temperature monitoring, reverse current protection, shutdown mode, charging current monitor, under voltage lockout, automatic recharge and status indicator.

EMC5040技术特性
Programmable charge current up to 1.2A
No MOSFET, sense resistor or blocking diode required
Complete linear charger in TDFN-10 for single cell li-ion batteries
Thermal regulation maximizes charge rate without risk of overheating
Thermistor input for temperature qualified charging
Charges single cell Li-ion batteries directly from USB port.
Preset 4.2V charge voltage with ±1% accuracy
Automatic recharge
Charge status indicator
C/10 charge termination
Battery reverse leakage current less than 1uA

EMC5040应用领域
Wireless handsets
Hand-held instruments
Portable information appliances