The ISL9209B is an integrated circuit (IC) optimized to
provide a redundant safety protection to a Li-ion battery from
failures of a charging system. The IC monitors the input
voltage, the battery voltage and the charge current. When
any of the three parameters exceeds its limit, the IC turns off
an internal P-Channel MOSFET to remove the power from
the charging system. In addition to the above protected
parameters, the IC also monitors its own internal
temperature and turns off the P-Channel MOSFET when the
temperature exceeds +140°C. Together with the battery
charger IC and the protection module in a battery pack, the
charging system using the ISL9209B has triple-level
protection and is two-fault tolerant.
The IC is designed to turn on the internal PFET slowly to
avoid inrush current at power up but will turn off the PFET
quickly when the input is overvoltage in order to remove the
power before any damage occurs. The ISL9209B has a logic
warning output to indicate the fault and an enable input to
allow the system to remove the input power.

Features
• Fully Integrated Protection Circuit for Three Protected
Variables
• High Accuracy Protection Thresholds
• User Programmable Overcurrent Protection Threshold
• Input Overvoltage Protection in Less than 1μs
• High Immunity of False Triggering Under Transients
• Warning Output to Indicate the Occurrence of Faults
• Enable Input
• Easy to Use
• Thermal Enhanced TDFN Package
• Pb-Free Plus Anneal Available (RoHS Compliant)

Applications
• Cell Phones
• Digital Still Cameras
• PDAs and Smart Phones
• Portable Instruments
• Desktop Chargers