Features

• 2 μA shipment - DEEP SLEEP mode current and 5 μA standby consumption

(with VREG LDO active) standby consumption (with VREG LDO active)

• Integrated 3.3 V VREG LDO for supplying MCU and LEDs

• Measures cell voltage (3 to 5 cells), with over/undervoltage detection and

balance undervoltage protection

• 12-bit voltage measurement with maximum error of ±15 mV in the [1.5–4.5] V

range, for -40 °C < TJ < 105 °C

• Measures stack voltage, with over/under voltage detection and plausibility check

vs. sum of cells

• Measures pack temperature via NTC, with over/undertemperature detection

• Ratiometric temperature measurement with ±0.8 max. gain error in the [0.2–

VREG] V range, for -40 °C < TJ < 105 °C

• Measures battery current, with Coulomb counting, overcurrent (both directions)

and short-circuit in discharge protection.

• 16-bit signed current measurement with 0.1 full scale error at room

temperature

• I2C peripheral for device programming and data transfers over I2C bus

• Cell balancing supporting up to 70 mA per cell

• Dual configurable HS/LS predriver for pack relay management

• Pack fuse management

• Embedded NVM for configuration parameters storage

• High hotplug robustness

Description

L9961 is part of a complete battery pack monitoring, balancing, and protecting system for Li-Ion and Li-Polymer

cells in 3, 4 or 5 series configurations. The L9961 uses a high precision ADC to provide cell voltage, stack

voltage and temperature conversion via external NTC. Voltage monitoring functions are cyclically performed with

a programmable loop time. Stack current is also monitored via a high accuracy CSA, continuously running and

performing also Coulomb counting. Cell balancing is available and can be simultaneously activated on all cells.

IC configuration and information exchange for SOC/SOH estimation are performed via I2C peripheral. The IC

also integrates a dual pre-driver programmable in both HS/LS configurations for driving pack relays. L9961 also

implements battery pack fuse protection to prevent fire and explosion hazards. A 3.3 V regulator with a high

current capability is available for supplying pack controller and other external circuitry in both standby and normal

operation modes. The IC protects the battery pack against over/under voltage conditions and monitors for over/

under temperature. It also features protection against overcurrent (both directions) and short-circuit in discharge

events. Safety-relevant configurations can be stored in the internal NVM to avoid re-programming the device at

each wakeup.

Applications

• Cordless power tools

• Backup energy storage systems and UPS

• Light electric vehicles (e-bikes, scooters, etc)

• Portable and semi-portable equipment

• Medical equipment