L9965T - Automotive Battery Monitoring IC | STMicroelectronics
MPN: L9965T β Active| 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 |
Drop-in alternatives for L9965T β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
L9965T-Q1
β Drop-Inπ Reference alternative (not in catalog)
L9965
β Drop-Inπ Reference alternative (not in catalog)
L9965T Maximum Ratings & Electrical Characteristics
| Supply Voltage Range | 4.5 V to 36 V |
| Operating Temperature Range | -40Β°C to +125Β°C |
| Voltage Measurement Accuracy | Β±10 mV |
| Current Sensing Range | Β±100 A (with external shunt) |
| ADC Resolution | 12-bit |
| Communication Interface | SPI (up to 5 MHz) |
| Quiescent Current | 50 Β΅A (typ) |
| Package | TQFP-32 (7x7 mm) |
| Mounting Type | Surface Mount |
| Number of Channels | 1 voltage, 1 current, 1 temperature |
| Diagnostic Features | Open-wire detection, overvoltage/undervoltage |
| AEC-Q100 Qualification | Yes (Grade 1) |
| RoHS Status | Compliant |
| REACH Status | Compliant |
| MSL Level | 3 (168 hours) |
L9965T Pin Configuration
| Pin 1 | VBAT β Battery voltage sense input |
| Pin 2 | GND β Ground |
| Pin 3 | VSENSE+ β Current sense positive input |
| Pin 4 | VSENSE- β Current sense negative input |
| Pin 5 | TEMP β Temperature sensor input (NTC) |
| Pin 6 | VDD β Internal LDO output (3.3V) |
| Pin 7 | SCLK β SPI clock |
| Pin 8 | MOSI β SPI data input |
| Pin 9 | MISO β SPI data output |
| Pin 10 | CS β SPI chip select |
| Pin 11 | INT β Interrupt output |
| Pin 12 | GND β Ground |
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
L9965T is suitable for 6 applications: Automotive Start-Stop Systems, Electric Vehicle Battery Management, Industrial Backup Power Systems, Telematics Units, Marine Battery Monitoring, Recreational Vehicle (RV) Power Management.
Automotive Start-Stop Systems
The L9965T monitors battery voltage, current, and temperature to ensure reliable engine restart in start-stop systems. Its high accuracy and wide operating temperature range make it ideal for under-hood environments. The SPI interface allows fast data transfer to the engine control unit (ECU) for real-time battery state estimation. With a quiescent current of 50 Β΅A, it minimizes battery drain during engine-off periods. The device's diagnostic features, such as open-wire detection, enhance system reliability by detecting sensor failures early.
Recommended
Electric Vehicle Battery Management
In electric vehicles, the L9965T provides accurate battery monitoring for state-of-charge (SoC) and state-of-health (SoH) estimation. Its 12-bit ADC and Β±10 mV voltage accuracy ensure precise measurements, which are critical for maximizing battery life and range. The device can be used in conjunction with a host microcontroller to implement cell balancing and thermal management. The wide supply voltage range (4.5V to 36V) accommodates battery voltage variations during charging and discharging. The AEC-Q100 Grade 1 qualification ensures reliable operation in the harsh automotive environment.
Recommended
Industrial Backup Power Systems
The L9965T is used in industrial backup power systems to monitor lead-acid battery health. Its low quiescent current (50 Β΅A) is ideal for always-on monitoring without draining the battery. The SPI interface allows integration with industrial controllers for remote monitoring and diagnostics. The device's wide operating temperature range (-40Β°C to +125Β°C) makes it suitable for outdoor and harsh industrial environments. The diagnostic features help detect battery degradation early, enabling predictive maintenance.
Recommended
Telematics Units
In telematics units, the L9965T monitors the vehicle battery to ensure reliable operation of GPS and communication modules. Its low quiescent current is crucial for minimizing battery drain when the vehicle is parked. The device provides accurate battery voltage and current data, which can be transmitted to a cloud server for fleet management. The SPI interface enables seamless integration with telematics microcontrollers. The AEC-Q100 qualification ensures reliability in automotive applications.
Recommended
Marine Battery Monitoring
The L9965T is suitable for marine battery monitoring systems, where reliable battery health is critical for safety. Its wide operating temperature range and robust design make it suitable for marine environments. The device monitors battery voltage, current, and temperature to provide accurate state-of-charge information. The SPI interface allows integration with marine navigation systems. The low quiescent current ensures minimal battery drain during long periods of inactivity.
Recommended
Recreational Vehicle (RV) Power Management
In RVs, the L9965T monitors the house battery to manage power consumption and charging. Its high accuracy ensures optimal battery usage, extending battery life. The device can be used to control charging from solar panels or generators. The SPI interface allows integration with RV power management systems. The wide supply voltage range accommodates battery voltage variations during charging. The diagnostic features help detect battery issues early, preventing unexpected failures.
Recommended
Recommended Products Summary
Engineering reference data for L9965T β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | L9965T-Q1 | L9965 | BQ76920 |
|---|---|---|---|---|
| Package | TQFP-32 | TQFP-32 | TQFP-32 | TSSOP-20 |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | Texas Instruments |
| Supply Voltage Range | 4.5V to 36V | 4.5V to 36V | 4.5V to 36V | 3.6V to 26.4V |
| Voltage Measurement Accuracy | Β±10 mV | Β±10 mV | Β±10 mV | Β±10 mV |
| ADC Resolution | 12-bit | 12-bit | 12-bit | 16-bit |
| Communication Interface | SPI (5 MHz) | SPI (5 MHz) | SPI (5 MHz) | I2C |
| Quiescent Current | 50 Β΅A | 50 Β΅A | 50 Β΅A | 4 Β΅A |
| AEC-Q100 Qualification | Yes (Grade 1) | Yes (Grade 1) | Yes (Grade 1) | No |
Key Differentiators
- AEC-Q100 Grade 1 qualification (vs BQ76920)
- Wide supply voltage range (4.5V to 36V) (vs BQ76920)
- SPI interface with 5 MHz clock (vs BQ76920)
Design Notes
The L9965T has an internal LDO that provides a 3.3V output for the digital core. Ensure that the VDD pin is decoupled with a 100nF ceramic capacitor placed close to the pin. The VBAT pin should be protected with a series resistor and TVS diode to handle voltage transients up to 40V.
For accurate current sensing, place the shunt resistor close to the VSENSE+ and VSENSE- pins and use Kelvin connections to minimize parasitic resistance. Keep the sense traces short and shielded from noise. The SPI lines should be routed with controlled impedance and kept away from high-current paths.
The L9965T dissipates minimal power, but in high-temperature environments, ensure adequate PCB copper area for heat dissipation. The TQFP-32 package has a thermal resistance of approximately 40Β°C/W. For continuous operation at 125Β°C ambient, keep the power dissipation below 1W.
Compliance Information
AEC-Q100 Grade 1 qualified per STMicroelectronics product page. RoHS and REACH compliant.
