■ Features
 Programmable charge current up to 1A
 No MOSFET, sense resistor or blocking diode required
 Complete linear charger in small package for single cell lithium-ion batteries
 Constant-current/constant-voltage operation with thermal regulation to maximize charge rate without risk of overheating
 Charges single cell li-ion batteries directly from USB port
 Preset 4.2V
 Monitor output charge current
 default charging voltage of 4.2V1%, can be adjusted by the FB
 Automatic recharge
 Charge status output pin
 1/10 charge current termination
 40μA supply current in shutdown
 2.9V trickle charge threshold
 Soft-Start limits inrush current
 OVP protection function , the input is higher than 6.8V, stop charging
 Output with protection against anti-irrigation
 Available in eSOP-8/PP or eMSOP-8/PP Package
 When you unplug VIN , the IC does not consume battery power
■ General Description
The XT2051 is a constant- current / constant- voltage charger circuit for single cell lithium-ion batteries. The device includes an internal power transistor, does not need external current sense resistor and blocking diode in applications. XT2051 requires minimal external components, and meet the USB bus specification, is very suitable for portable applications in the field.
Thermal modulation circuit can control the internal chip temperature in a safe range when the device power dissipation be relatively large or the ambient temperature be higher. Within a fixed constant charge voltage 4.2V, can also be adjusted by an external resistor. Charge current set by an external resistor.
When the input voltage (AC adapter or USB power supply) power is lost, XT2051 automatically enters a low power sleep mode, then the battery current consumption is less than 0.1μA. Built-in protection circuits against irrigation, when the battery voltage is higher than the input voltage, automatically turn off built-in power MOSFET. Other features include low input voltage latch, automatic recharge, the battery temperature monitoring, Built - in OVP protection and charge status / charge status indication functions. XT2051 uses thermally enhanced 8-pin small outline package eSOP-8/PP or eMSOP-8/PP.
■ Applications
 Mobile phones
 Digital Cameras
 MP4 Player
 Bluetooth applications
 Electronic Dictionary
 portable devices
 all kinds of charger
 Mobile power