L9924-TR - 24V Alternator Regulator IC | STMicroelectronics | Automotive
MPN: L9924-TR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.5 | $12.50 |
| 10 | $11.25 | $112.50 |
| 100 | $10 | $1,000.00 |
| 500 | $9 | $4,500.00 |
| 1,000 | $8.1 | $8,100.00 |
L9924-TR Overview
An alternator regulator is a critical component in vehicle electrical systems that maintains the output voltage of the alternator within a specified range to charge the battery and power electrical loads. The L9924-TR belongs to the category of power management ICs, specifically specialized power ICs for automotive applications. It sits within the hierarchy: alternator regulator -> voltage regulator -> power management IC -> semiconductor. This regulator ensures stable voltage output despite variations in engine speed and electrical load, protecting sensitive electronics and ensuring reliable operation.
Key features of the L9924-TR include support for multiple communication protocols (RCV, PCM, C_term, and BSS), enabling flexible integration with vehicle control units. The device is designed for harsh automotive environments, with a maximum operating temperature of 155°C, making it suitable for under-hood applications. The SiP approach combines the power stage and microcontroller in a single package, reducing board space and improving reliability.
Technically, the L9924-TR uses a non-monolithic approach, where the smart power alternator regulator IC and the 8-bit microcontroller are co-packaged. This allows for sophisticated control algorithms, such as load response control and battery state monitoring, while maintaining high power handling capability. The device supports both 12 V and 24 V systems, providing flexibility for different vehicle platforms.
Typical applications include passenger cars, commercial trucks, agricultural vehicles, and construction equipment. In these applications, the L9924-TR ensures efficient battery charging, reduces fuel consumption, and extends battery life. Its robust design and communication capabilities make it ideal for modern vehicles with increasing electrical loads.
When designing with the L9924-TR, engineers must consider the thermal management of the HTQFP package, as the power dissipation can be significant. Adequate PCB copper area and airflow are recommended to keep the junction temperature within limits. Additionally, the communication protocol selection (RCV, PCM, C_term) should be matched to the vehicle's existing control architecture to ensure seamless integration.
Drop-in alternatives for L9924-TR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with L9924-TR (same form factor and footprint) — differing in Architecture, Communication Protocols.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
L9924
✅ Drop-In✓ In Stock
$8.1 / Unit
View Datasheet →L9924TR
✅ Drop-In📋 Reference alternative (not in catalog)
L9924-TR Maximum Ratings & Electrical Characteristics
| Function | Alternator regulator IC |
| System Voltage | 12 V and 24 V |
| Package | HTQFP-44 |
| Terminal Form | Gull Wing |
| Number of Terminals | 44 |
| Package Shape | Square |
| Maximum Operating Temperature | 155 °C |
| Communication Protocols | RCV, PCM, C_term, BSS |
| Architecture | System-In-Package (SiP) with 8-bit microcontroller |
| Mounting Type | Surface Mount |
| Application | Automotive (cars, commercial, agricultural vehicles) |
L9924-TR Pin Configuration
| Pin 1 | B+ — Battery positive sense input |
| Pin 2 | B- — Battery negative sense input |
| Pin 3 | FLD — Field driver output |
| Pin 4 | RCV — Communication line RCV |
| Pin 5 | PCM — Communication line PCM |
| Pin 6 | C_term — Communication line C_term |
| Pin 7 | BSS — Communication line BSS |
| Pin 8 | VCC — Power supply for internal microcontroller |
| Pin 9 | GND — Ground |
| Pin 10 | TEMP — Temperature sensor input |
| Pin 11 | LAMP — Charge indicator lamp output |
| Pin 12 | IGN — Ignition switch input |
Typical Applications
L9924-TR is suitable for 6 applications: Passenger Car Alternator Regulation, Commercial Truck Alternator Regulation, Agricultural Vehicle Alternator Regulation, Construction Equipment Alternator Regulation, Marine Alternator Regulation, Military Vehicle Alternator Regulation.
Passenger Car Alternator Regulation
The L9924-TR is used in passenger cars to regulate the alternator output voltage, ensuring efficient battery charging and stable electrical supply. It supports 12 V systems and communicates with the engine control unit via RCV or PCM protocols. The integrated microcontroller enables advanced load response control, reducing engine load and improving fuel efficiency. With a maximum operating temperature of 155°C, it withstands under-hood conditions. The SiP design saves space and enhances reliability compared to discrete solutions.
Recommended
Commercial Truck Alternator Regulation
For commercial trucks, the L9924-TR supports 24 V systems, which are standard in heavy-duty vehicles. It provides robust voltage regulation under varying loads and engine speeds. The C_term and BSS protocols allow integration with truck body controllers and battery management systems. The high-temperature rating ensures reliable operation in demanding environments. The SiP solution reduces the number of external components, simplifying assembly and improving durability.
Recommended
Agricultural Vehicle Alternator Regulation
Agricultural vehicles often operate in dusty, high-vibration environments. The L9924-TR's robust design and 155°C maximum operating temperature make it suitable for such conditions. It supports 12 V and 24 V systems, accommodating various tractor and harvester platforms. The communication protocols enable remote monitoring and control, improving fleet management. The integrated microcontroller allows for custom control algorithms to optimize charging based on battery state and load.
Recommended
Construction Equipment Alternator Regulation
Construction equipment like excavators and loaders require reliable alternator regulation to power hydraulic systems and electronics. The L9924-TR supports 24 V systems common in this equipment. Its communication protocols (RCV, PCM, C_term) allow integration with machine control systems. The SiP design withstands shock and vibration, ensuring long-term reliability. The high-temperature rating is critical for engine compartments where temperatures can exceed 100°C.
Recommended
Marine Alternator Regulation
In marine applications, the L9924-TR can regulate alternators in boats and yachts, supporting 12 V and 24 V systems. Its sealed package and high-temperature rating make it suitable for engine rooms. The communication protocols enable integration with onboard monitoring systems. The SiP solution reduces the risk of corrosion-related failures by minimizing external connections. However, additional conformal coating may be required for saltwater environments.
Recommended
Military Vehicle Alternator Regulation
Military vehicles require rugged, reliable alternator regulators. The L9924-TR's wide temperature range and robust SiP design meet military standards. It supports 24 V systems used in many military platforms. The communication protocols allow secure integration with vehicle networks. The high-temperature rating ensures operation in extreme climates. The integrated microcontroller enables fail-safe features, enhancing mission reliability.
Recommended
Engineering reference data for L9924-TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | L9924 | L9924TR |
|---|---|---|---|
| Package | HTQFP-44 | HTQFP-44 | HTQFP-44 |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| System Voltage | 12 V and 24 V | 12 V and 24 V | 12 V and 24 V |
| Communication Protocols | RCV, PCM, C_term, BSS | RCV, PCM, C_term, BSS | RCV, PCM, C_term, BSS |
| Maximum Operating Temperature | 155 °C | 155 °C | 155 °C |
| Architecture | SiP with 8-bit MCU | SiP with 8-bit MCU | SiP with 8-bit MCU |
| Terminal Form | Gull Wing | Gull Wing | Gull Wing |
| Number of Terminals | 44 | 44 | 44 |
Key Differentiators
- System-In-Package with integrated 8-bit microcontroller (vs L9924)
- Supports multiple communication protocols (RCV, PCM, C_term, BSS) (vs L9924)
- High maximum operating temperature of 155°C (vs L9924)
Design Notes
The L9924-TR can dissipate significant power in the HTQFP-44 package. Ensure adequate PCB copper area and thermal vias to keep the junction temperature below the maximum rating. For high ambient temperatures (e.g., 105°C), consider forced airflow or a heatsink. The thermal resistance of the package is not specified in the available data; use typical values for HTQFP-44 (around 30-40°C/W) for initial calculations.
Place decoupling capacitors close to the VCC and power pins to filter noise. Use a 100nF ceramic capacitor for high-frequency bypass and a 10uF electrolytic capacitor for bulk decoupling. Ensure the ground plane is solid and connected to the exposed pad (if present) for thermal and electrical performance. Follow the layout guidelines in the ST datasheet for optimal performance.
Do not exceed the maximum operating temperature of 155°C. Ensure the communication protocol (RCV, PCM, C_term, BSS) is correctly configured to match the vehicle's control unit. Incorrect protocol selection can lead to communication failures. Also, verify the input voltage range for the B+ and B- sense lines to avoid overvoltage damage.
Compliance Information
Compliance information not specified in the available data. Refer to the STMicroelectronics datasheet or contact the manufacturer for RoHS, REACH, and AEC-Q100 status.
