L9965A - Automotive Battery Monitoring IC | STMicroelectronics
MPN： L9965A ✓ 啟用中L9965A 概覽
What is a battery monitoring IC? A battery monitoring IC is a specialized integrated circuit that measures and reports the state of a battery, including voltage, current, temperature, and state-of-charge (SoC). It is a critical component in battery management systems (BMS), which ensure safe and efficient battery operation. In the system hierarchy, a battery monitoring IC belongs to the battery management IC category, which is part of the broader power management IC family. These ICs are essential in automotive, industrial, and consumer applications where battery health and safety are paramount.
Key features of the L9965A include a 12-bit ADC with a measurement accuracy of ±1%, a LIN transceiver compliant with LIN 2.2A, and a wide operating temperature range of -40°C to +125°C. The device also features a programmable watchdog timer, a 16-bit CRC for data integrity, and a low-power sleep mode with a quiescent current of 10 µA. These features enable reliable and accurate battery monitoring in harsh automotive environments.
Technically, the L9965A employs a precision bandgap reference and a successive-approximation register (SAR) ADC architecture to achieve high measurement accuracy. The integrated LIN transceiver supports communication with the vehicle's body control module (BCM) at data rates up to 20 kbps. The device also includes a 5V regulator output for powering external sensors, enhancing its versatility in BMS designs.
Typical applications include automotive start-stop systems, battery state-of-health (SoH) monitoring, and aftermarket battery management systems. The L9965A's high accuracy and robust communication interface make it ideal for monitoring lead-acid batteries in vehicles, where precise voltage and current measurements are critical for engine start-stop decisions and battery longevity.
When designing with the L9965A, ensure proper decoupling of the supply pins and place the device close to the battery sense points to minimize noise. The LIN bus requires a 1kΩ pull-up resistor to the battery voltage, and the watchdog timer should be configured according to the system's communication schedule to avoid false resets.
直接替換替代品，適用於 L9965A — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
L9965B
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
L9965A 規格
| Supply Voltage Range | 4.5 V to 36 V |
| ADC Resolution | 12-bit |
| Measurement Accuracy | ±1% |
| LIN Transceiver | LIN 2.2A compliant |
| LIN Data Rate | 20 kbps |
| 工作溫度範圍 | -40°C to +125°C |
| Quiescent Current (Sleep Mode) | 10 µA |
| Watchdog Timer | Programmable |
| CRC | 16-bit |
| Regulator Output | 5 V |
| 封裝 | VQFN-32 |
| 安裝類型 | Surface Mount |
| RoHS 狀態 | Compliant |
| AEC-Q100 | Qualified |
| Communication Interface | LIN |
L9965A 腳位配置
| 腳位 1 | VBAT — Battery voltage sense input |
| 腳位 2 | GND — Ground |
| 腳位 3 | LIN — LIN bus communication |
| 腳位 4 | VCC — Supply voltage |
| 腳位 5 | VSENSE — Current sense input |
| 腳位 6 | TSENSE — Temperature sense input |
| 腳位 7 | REG5 — 5V regulator output |
| 腳位 8 | WAKE — Wake-up input |
| 腳位 9 | SCLK — Serial clock |
| 腳位 10 | SDI — Serial data input |
| 腳位 11 | SDO — Serial data output |
| 腳位 12 | CS — Chip select |
典型應用
L9965A 適用於 6 應用s: Automotive Start-Stop Systems, Battery State-of-Health (SoH) Monitoring, Aftermarket Battery Management Systems, Electric Vehicle (EV) Battery Monitoring, Industrial Battery Backup Systems, Marine and RV Battery Monitoring.
Automotive Start-Stop Systems
The L9965A monitors battery voltage and current to enable efficient engine start-stop functionality. Its high accuracy (±1%) ensures reliable state-of-charge estimation, while the LIN interface communicates with the vehicle's body control module. The wide supply range (4.5V-36V) accommodates 12V and 24V systems, and the AEC-Q100 qualification ensures reliability in harsh automotive environments. In a typical start-stop system, the L9965A is placed near the battery, measuring voltage and current to determine when to stop and restart the engine, reducing fuel consumption and emissions.
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Battery State-of-Health (SoH) Monitoring
The L9965A provides precise voltage, current, and temperature measurements essential for assessing battery state-of-health. Its 12-bit ADC and ±1% accuracy enable accurate tracking of battery degradation over time. The integrated LIN transceiver allows data transmission to a central monitoring unit, facilitating predictive maintenance. In a SoH monitoring system, the L9965A continuously samples battery parameters and calculates internal resistance and capacity fade, helping to extend battery life and prevent unexpected failures.
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Aftermarket Battery Management Systems
The L9965A is ideal for aftermarket BMS modules that monitor lead-acid batteries in vehicles. Its compact VQFN-32 package and low sleep current (10 µA) make it suitable for always-on monitoring. The LIN interface simplifies integration with existing vehicle networks, and the 5V regulator output can power external sensors. In an aftermarket BMS, the L9965A measures battery parameters and provides alerts via LIN, enabling users to monitor battery health through a smartphone app or dashboard display.
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Electric Vehicle (EV) Battery Monitoring
Although designed for 12V lead-acid batteries, the L9965A can be used in auxiliary battery monitoring in EVs. Its wide supply range and automotive qualification make it suitable for monitoring the 12V auxiliary battery that powers vehicle electronics. The LIN interface communicates with the vehicle's main BMS, providing status updates. In an EV, the L9965A ensures the auxiliary battery is charged and healthy, supporting critical functions like braking and steering systems.
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Industrial Battery Backup Systems
The L9965A can monitor backup batteries in industrial systems, such as UPS and telecom equipment. Its wide temperature range and robust communication interface ensure reliable operation in harsh environments. The device's low power consumption is beneficial for always-on monitoring. In an industrial backup system, the L9965A tracks battery health and alerts maintenance personnel via LIN or a local MCU, preventing downtime due to battery failure.
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Marine and RV Battery Monitoring
The L9965A is suitable for monitoring batteries in marine and recreational vehicles, where reliable power is critical. Its automotive-grade reliability and wide supply range make it ideal for 12V systems. The LIN interface can be adapted for use with marine electronics. In a marine or RV application, the L9965A monitors battery voltage and current, providing data to a display or controller to prevent over-discharge and extend battery life.
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推薦產品摘要
工程參考資料，適用於 L9965A — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | L9965B | BQ76940 | LTC6811 |
|---|---|---|---|---|
| Package | VQFN-32 | VQFN-32 (same) | TQFP-64 (different) | LQFP-48 (different) |
| Brand | STMicroelectronics | STMicroelectronics | Texas Instruments | Analog Devices |
| ADC Resolution | 12-bit | 16-bit | 16-bit | 16-bit |
| Supply Voltage Range | 4.5V to 36V | 4.5V to 36V | 6V to 60V | 6V to 60V |
| Communication Interface | LIN | LIN | I2C/SPI | SPI |
| Operating Temperature Range | -40°C to +125°C | -40°C to +125°C | -40°C to +85°C | -40°C to +125°C |
| Quiescent Current (Sleep) | 10 µA | 10 µA | 20 µA | 12 µA |
| AEC-Q100 Qualified | Yes | Yes | No | Yes |
主要差異化特點
- Integrated LIN transceiver (對比BQ76940)
- AEC-Q100 qualification (對比BQ76940)
- Low sleep current (對比LTC6811)
設計說明
Ensure the supply voltage (VCC) is within the 4.5V to 36V range and is properly decoupled with a 100nF ceramic capacitor placed close to the VCC pin. Additionally, a 10µF bulk capacitor is recommended to handle transient currents during battery monitoring operations.
Place the L9965A close to the battery sense points to minimize trace resistance and noise. Use Kelvin connections for the current sense inputs to improve measurement accuracy. Keep the LIN bus traces short and shielded to avoid EMI interference.
Do not exceed the absolute maximum ratings, especially on the VBAT and LIN pins. Ensure the LIN bus has a 1kΩ pull-up resistor to the battery voltage as per LIN specifications. Configure the watchdog timer appropriately to avoid false resets during normal communication.
合規資訊
RoHS compliant and AEC-Q100 qualified per STMicroelectronics. Halogen-free status not specified in available data.
