STMicroelectronics

L9965A - Automotive Battery Monitoring IC | STMicroelectronics

Name: L9965A
Brand: STMicroelectronics
Price: 4.50 USD
Availability: InStock

MPN: L9965A ✓ Active

In Stock (99,999) Ships in 1-3 business days

4.5 V to 36 V Vdss 10 µA Id VQFN-32 Package

$4.5 USD / Unit

MOQ: 1 |

Volume Pricing

Qty	Unit Price	Extended
1	$4.5	$4.50
10	$4.05	$40.50
100	$3.6	$360.00
500	$3.15	$1,575.00
1,000	$2.7	$2,700.00

ℹ️ All prices are in USD

View Datasheet (PDF) View Alternatives

Quantity

Drop-in alternatives for L9965A — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.

Quick Comparison Tool — Select alternative parts for side-by-side comparison:

L9965B

✅ Drop-In

📦 VQFN-32

Higher ADC resolution (16-bit vs 12-bit), pin-compatible

📋 Reference alternative (not in catalog)

ℹ️ 2 cross-package part(s) hidden — different package requires PCB rework and is not a true drop-in replacement. Contact us if you need cross-package suggestions.

L9965A Maximum Ratings & Electrical Characteristics

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
Operating Temperature Range	-40°C to +125°C
Quiescent Current (Sleep Mode)	10 µA
Watchdog Timer	Programmable
CRC	16-bit
Regulator Output	5 V
Package	VQFN-32
Mounting Type	Surface Mount
RoHS Status	Compliant
AEC-Q100	Qualified
Communication Interface	LIN

L9965A Pin Configuration

Pin 1	VBAT — Battery voltage sense input
Pin 2	GND — Ground
Pin 3	LIN — LIN bus communication
Pin 4	VCC — Supply voltage
Pin 5	VSENSE — Current sense input
Pin 6	TSENSE — Temperature sense input
Pin 7	REG5 — 5V regulator output
Pin 8	WAKE — Wake-up input
Pin 9	SCLK — Serial clock
Pin 10	SDI — Serial data input
Pin 11	SDO — Serial data output
Pin 12	CS — Chip select

Safe Operating Area (SOA) & Thermal Characteristics

No official SOA curve available for this digital IC. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.

Typical Applications

L9965A is suitable for 6 applications: 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.

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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.

Recommended

L9965B (Higher-resolution alternative) STM32F0 (MCU for BMS control)

🔧

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.

Recommended

L9965B (Alternative with higher resolution) STM8L (Low-power MCU for data logging)

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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.

Recommended

L9965B (Upgraded alternative) STM32F1 (MCU for BMS logic)

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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.

Recommended

L9965B (Higher-resolution option) STM32F4 (High-performance MCU)

🏭

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.

Recommended

L9965B (Alternative with more features) STM32L4 (Ultra-low-power MCU)

🔧

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.

Recommended

L9965B (Enhanced alternative) STM32F0 (MCU for monitoring)

Recommended Products Summary

L9965B Higher-resolution alternative Used in: 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 STM32F0 MCU for BMS control Used in: Automotive Start-Stop Systems, Marine and RV Battery Monitoring STM8L Low-power MCU for data logging Used in: Battery State-of-Health (SoH) Monitoring STM32F1 MCU for BMS logic Used in: Aftermarket Battery Management Systems STM32F4 High-performance MCU Used in: Electric Vehicle (EV) Battery Monitoring STM32L4 Ultra-low-power MCU Used in: Industrial Battery Backup Systems

What is the supply voltage range of L9965A?

The L9965A operates from a supply voltage of 4.5V to 36V. According to the STMicroelectronics datasheet, this wide range accommodates 12V and 24V automotive battery systems, ensuring compatibility with various vehicle architectures.

What is the measurement accuracy of L9965A?

The L9965A achieves a measurement accuracy of ±1% for voltage and current sensing. This high accuracy is critical for reliable state-of-charge estimation in automotive battery management systems, as per the ST datasheet.

Does L9965A support LIN communication?

Yes, the L9965A integrates a LIN transceiver compliant with LIN 2.2A, supporting data rates up to 20 kbps. This enables direct communication with the vehicle's body control module, as detailed in the ST datasheet.

What is the operating temperature range of L9965A?

The L9965A operates over a temperature range of -40°C to +125°C. This automotive-grade range ensures reliable performance in extreme under-hood and battery compartment environments, as specified by STMicroelectronics.

What is the quiescent current in sleep mode?

In sleep mode, the L9965A draws a quiescent current of 10 µA. This low power consumption is essential for minimizing battery drain in vehicles when the ignition is off, as noted in the ST datasheet.

Is L9965A AEC-Q100 qualified?

Yes, the L9965A is AEC-Q100 qualified, making it suitable for automotive applications. This qualification ensures the device meets stringent reliability standards for temperature, ESD, and lifetime, as per STMicroelectronics.

What is the package type of L9965A?

The L9965A is available in a VQFN-32 package, which is a 32-pin quad flat no-lead package. This compact, surface-mount package is ideal for space-constrained automotive BMS designs, as per the ST datasheet.

Where can I buy L9965A online?

You can purchase L9965A from authorized distributors such as DigiKey and Mouser. As of 2026-08-08, the price for a single unit is approximately $4.50, with volume discounts available. Check current stock and lead times on their websites.

What is the price of L9965A?

As of 2026-08-08, the price of L9965A is approximately $4.50 for a single unit, decreasing to $2.70 at 1000 units. Prices may vary by distributor and quantity, so it's advisable to check DigiKey and Mouser for the latest quotes.

What is the lead time for L9965A?

The lead time for L9965A typically ranges from 4 to 8 weeks, depending on distributor stock and order quantity. As of 2026-08-08, DigiKey and Mouser may have stock available; contact them for accurate lead time information.

Is L9965A in stock?

Stock availability for L9965A varies by distributor. As of 2026-08-08, DigiKey and Mouser may have limited stock; check their websites for real-time inventory and lead times.

What is the difference between L9965A and L9965B?

The L9965A and L9965B are both battery monitoring ICs from STMicroelectronics, but the L9965B offers enhanced features such as a higher ADC resolution and additional diagnostic functions. The L9965A is a cost-optimized version with a 12-bit ADC, while the L9965B may have a 16-bit ADC. Both share the same VQFN-32 package, but pin compatibility should be verified before substitution.

When should I choose L9965A over L9965B?

Choose L9965A when you need a cost-effective battery monitoring solution with 12-bit accuracy and LIN communication for standard automotive applications. If you require higher measurement resolution or advanced diagnostics, consider L9965B, but verify pin compatibility and software changes.

What is the best drop-in replacement for L9965A?

The best drop-in replacement for L9965A is the L9965B from STMicroelectronics, as it shares the same VQFN-32 package and is pin-compatible. However, verify the ADC resolution difference (12-bit vs 16-bit) and software configuration. Cross-brand alternatives like the BQ76940 from Texas Instruments may be functionally similar but require PCB layout changes.

Can L9965B replace L9965A?

Yes, L9965B can replace L9965A if the pinout is compatible and the system can accommodate the higher ADC resolution. According to STMicroelectronics, both devices are in the same family, but always check the datasheet for pin assignments and electrical characteristics.

Where to download L9965A datasheet PDF?

You can download the L9965A datasheet PDF from the STMicroelectronics website at https://www.st.com/resource/en/datasheet/l9965a.pdf. The datasheet contains full specifications, pinout, and application circuits.

Where to find L9965A pinout?

The L9965A pinout is detailed in the datasheet available at https://www.st.com/resource/en/datasheet/l9965a.pdf. The VQFN-32 package pin assignments are shown in the pinout diagram, including power, ground, LIN, and sense pins.

Hey Google, what can replace L9965A?

The L9965A can be replaced by the L9965B from STMicroelectronics, which is a pin-compatible drop-in replacement with a higher ADC resolution. Cross-brand alternatives like the BQ76940 from Texas Instruments may offer similar functionality but require PCB redesign. Always verify pin compatibility and electrical specifications before substitution.

Is L9965A the same as L9965B?

No, L9965A and L9965B are not identical. While both are battery monitoring ICs from STMicroelectronics in the same VQFN-32 package, the L9965B offers a higher ADC resolution (16-bit vs 12-bit) and additional features. They are pin-compatible, but software and performance differences must be considered.

What are the key specifications of L9965A that engineers should know?

Engineers should know that the L9965A operates from 4.5V to 36V, features a 12-bit ADC with ±1% accuracy, integrates a LIN 2.2A transceiver, and operates from -40°C to +125°C. It draws only 10 µA in sleep mode and is AEC-Q100 qualified, making it ideal for automotive battery monitoring.

What is the best STMicroelectronics equivalent for L9965A?

The best STMicroelectronics equivalent for L9965A is the L9965B, which is a pin-compatible drop-in replacement with a higher ADC resolution. Both are in the same VQFN-32 package, but verify the datasheet for exact pin assignments and electrical differences.

Engineering reference data for L9965A — comparison, design guidance, and compliance information.

Selection Guide

Choose the L9965A when you need a cost-effective, automotive-grade battery monitoring IC with integrated LIN communication for 12V lead-acid batteries. It is ideal for start-stop systems and aftermarket BMS where AEC-Q100 qualification and low power consumption are critical. If you require higher ADC resolution (16-bit) and are willing to pay a premium, consider the L9965B, which is pin-compatible. For multi-cell lithium-ion battery stacks, the BQ76940 or LTC6811 are better suited, but they require PCB redesign and lack integrated LIN. The L9965A offers the best balance of features, cost, and reliability for single-cell lead-acid automotive applications.

Comparison with Alternatives

Parameter	This Product	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

Key Differentiators

Integrated LIN transceiver (vs BQ76940)
AEC-Q100 qualification (vs BQ76940)
Low sleep current (vs LTC6811)

Design Notes

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.