1 Features
• 4-, 5-, 6-, 7-, or 8-Series Cell Protection
• Individual Cell-Voltage Monitoring
• Low-Side NMOS FET Drive for Charge and
Discharge Control
• Compatible With 1-mΩ Current-Sense Resistor
• Supply-Voltage Range From 5.6 V to 40 V
• Integrated 3.3-V Micro-Power LDO Regulator
• Low Supply Current
– Normal Mode: 50 μA, Typical
– Shutdown Mode, LDO OFF: 5 μA, Typical
• 38-Pin TSSOP Package
• Internal 50-mA Automatic Cell Balancing

2 Applications
• Cordless Power Tools
• Cordless Lawn Equipment
• Electric Bikes
• UPS
• Light Electric Vehicles (LEV)

3 Description
The bq77908A is a battery protection and cell balancing device intended for Li-Ion and Li-Polymer battery packs.
The bq77908A monitors 4- to 8-series individual cell voltages and provides fast-acting outputs that may be used
to drive N-channel MOSFETs to interrupt the power path. Activation delays and recovery methods for safety
conditions are fully programmable in non-volatile memory.
Automatic cell balancing is provided using internal 50-mA cell circuits. A robust balancing algorithm ensures
optimum performance by maintaining all cell voltages in balance. Balancing may be configured to operate at all
times, only during charge, or can be disabled completely.