# L9961TR (Component)
## Description
Battery Multi-Function Controller IC Lithium Ion/Polymer 32-VFQFPN (5x5)
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 wake-up.
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
• I
2C 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
Applications
• Cordless power tools
• Backup energy storage systems and UPS
• Light electric vehicles (e-bikes, scooters, etc.)
• Portable and semi-portable equipment
• Medical equipment
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## Component Details
- **Owner:** adrian95
- **Created:** 6/16/2026
- **Last Updated:** 6/16/2026
- **Visibility:** Public
- **Part Type:** Integrated Circuit
- **Symbol Style:** parametric-v1
- **License:** https://creativecommons.org/licenses/by/4.0/
- **Manufacturer Name:** STMicroelectronics
- **Package or Case Code:** VFQFPN 5x5x1 32L P0.5
- **Manufacturer Part Number:** L9961TR
- **Datasheet URL:** https://www.st.com/resource/en/datasheet/l9961.pdf
- **Used in:** 1 project
## Distributor Pricing (qty 1)
*Pricing shown for quantity 1. For price breaks and other quantities, open in Flux.*
| Distributor | Unit Price (qty 1) | Stock |
|------------|--------------------|-------|
| [Arrow](https://www.arrow.com/en/products/l9961tr/stmicroelectronics.html?utm_currency=USD®ion=nac) | N/A | N/A |
| [Mouser](https://www.mouser.com/ProductDetail/STMicroelectronics/L9961TR?qs=Y0Uzf4wQF3nrETIguz2ELA%3D%3D) | $2.83 | 1.6K |
- **Part Type:** Integrated Circuits
- **Sub-Type:** Logic
- **Manufacturer:** STMicroelectronics
- **MPN:** L9961TR
- **Package / Case Code:** TO
- **Pin Count:** 33
- **Logic Function:** AND
## Pins
| Pin | Name | Type |
|-----|------|------|
| 1 | C0 | |
| 2 | ISENSEP | |
| 3 | ISENSEM | |
| 4 | GND | |
| 5 | SCL | |
| 6 | SDA | |
| 7 | RDY | |
| 8 | VREG | |
| 9 | NTC | |
| 10 | OD | |
| 11 | FAULTN_SAFE | |
| 12 | FAULTN | |
| 13 | GND | |
| 14 | WAKEUP | |
| 15 | NSHIP | |
| 16 | FUSE | |
| 17 | DCHG | |
| 18 | VSD | |
| 19 | VSC | |
| 20 | CHG | |
| 21 | VCP1M | |
| 22 | VCP1P | |
| 23 | VCP2M | |
| 24 | VCP2P | |
| 25 | VCP | |
| 26 | VB | |
| 27 | GND | |
| 28 | C5 | |
| 29 | C4 | |
| 30 | C3 | |
| 31 | C2 | |
| 32 | C1 | |
| 33 | EP | |
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*Generated from [https://www.flux.ai/adrian95/l9961tr](https://www.flux.ai/adrian95/l9961tr)*