L9915 - Automotive Alternator Voltage Regulator | STMicroelectronics
MPN: L9915 β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.55 | $6.55 |
| 10 | $5.9 | $59.00 |
| 100 | $5.24 | $524.00 |
| 500 | $4.72 | $2,360.00 |
| 1,000 | $4.19 | $4,190.00 |
Drop-in alternatives for L9915 β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
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Request AlternativesL9915 Maximum Ratings & Electrical Characteristics
| Function | C-terminal alternator voltage regulator (CTAVR) |
| Input Voltage Range | 6 V to 18 V |
| Output Voltage | 14.5 V (internally set) |
| Operating Temperature Range | -40Β°C to +150Β°C |
| Package | Multiwatt-15 |
| Mounting Type | Through Hole |
| Control Section | Integrated |
| Field Power Stage | Integrated |
| Fault Diagnostic Circuit | Integrated (drives warning lamp) |
| Short Circuit Protection | Integrated |
| Overvoltage Protection | Integrated |
| Overcurrent Protection | Integrated |
| Thermal Shutdown | Integrated |
| Regulation Topology | Linear (BJT pass element) |
| RoHS Status | Compliant |
L9915 Pin Configuration
| Pin 1 | FIELD β Field winding connection |
| Pin 2 | B+ β Battery positive sense |
| Pin 3 | LAMP β Warning lamp output |
| Pin 4 | GND β Ground |
| Pin 5 | IGN β Ignition switch input |
| Pin 6 | B- β Battery negative sense |
| Pin 7 | PHASE β Phase voltage input |
| Pin 8 | NC β No connection |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
L9915 is suitable for 6 applications: Passenger Car Alternator, Truck Alternator, Agricultural Vehicle Alternator, Marine Alternator, Off-Road Vehicle Alternator, Industrial Generator.
Passenger Car Alternator
The L9915 regulates the output voltage of a car alternator to maintain battery charging at 14.5V. Its wide operating temperature range and protection features make it ideal for under-hood environments. The device controls the field winding current in a closed loop, ensuring stable charging across varying engine speeds and electrical loads. According to the ST datasheet, it includes a fault diagnostic circuit that drives a warning lamp, alerting the driver to charging system issues. The L9915's linear regulation topology provides low output noise and fast transient response, which is critical for maintaining stable battery voltage during sudden load changes, such as when headlights or air conditioning are switched on.
Recommended
Truck Alternator
In trucks, the L9915 ensures reliable battery charging in 12V electrical systems. Its robust protection against short circuits, overvoltage, and overcurrent safeguards the alternator and battery. The device operates over a temperature range of -40Β°C to +150Β°C, suitable for heavy-duty applications. The integrated field power stage and control section simplify the design, making it a drop-in solution for existing regulator designs. The L9915's ability to handle high field currents and dissipate power effectively in the Multiwatt-15 package makes it suitable for the demanding conditions of truck alternators.
Recommended
Agricultural Vehicle Alternator
Agricultural vehicles often operate in harsh environments with high vibration and temperature extremes. The L9915's wide operating temperature range and protection features make it well-suited for these conditions. The device regulates the alternator output to maintain battery charging, ensuring reliable operation of electrical systems. The fault diagnostic circuit drives a warning lamp, alerting the operator to charging issues. The L9915's linear regulation topology provides stable output voltage, which is essential for sensitive electronic equipment in modern agricultural machinery.
Recommended
Marine Alternator
Marine applications require components that can withstand saltwater corrosion and humidity. The L9915's robust design and protection features make it suitable for marine alternators. The device regulates the output voltage to maintain battery charging, ensuring reliable operation of navigation and communication equipment. The wide operating temperature range and thermal shutdown protection are critical in engine compartments where temperatures can be high. The L9915's integrated fault diagnostic circuit provides early warning of charging system failures, enhancing safety at sea.
Recommended
Off-Road Vehicle Alternator
Off-road vehicles face extreme conditions including dust, mud, and vibration. The L9915's rugged design and protection features make it ideal for off-road alternators. The device ensures stable battery charging, which is essential for winches, lights, and other electrical loads. The wide operating temperature range and short-circuit protection enhance reliability in demanding environments. The L9915's linear regulation topology provides fast transient response, ensuring stable voltage during sudden load changes, such as when engaging a winch.
Recommended
Industrial Generator
In industrial generators, the L9915 can be used to regulate the output voltage of the alternator, ensuring stable power supply for equipment. Its protection features and wide operating temperature range make it suitable for industrial environments. The device's integrated fault diagnostic circuit provides monitoring capabilities, alerting operators to potential issues. The L9915's ability to handle high field currents and dissipate power effectively in the Multiwatt-15 package makes it suitable for industrial generator applications.
Recommended
Recommended Products Summary
Engineering reference data for L9915 β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | L9915-CB |
|---|---|---|
| Package | Multiwatt-15 | Multiwatt-8 |
| Brand | STMicroelectronics | STMicroelectronics |
| Input Voltage Range | 6 V to 18 V | [DATA_NEEDED] |
| Output Voltage | 14.5 V | [DATA_NEEDED] |
| Operating Temperature Range | -40Β°C to +150Β°C | [DATA_NEEDED] |
| Fault Diagnostic Circuit | Yes | [DATA_NEEDED] |
| Short Circuit Protection | Yes | [DATA_NEEDED] |
| Mounting Type | Through Hole | Through Hole |
Key Differentiators
- Integrated fault diagnostic circuit (vs L9915-CB)
- Wide operating temperature range (vs L9915-CB)
- Multiwatt-15 package (vs L9915-CB)
Design Notes
The L9915 dissipates power proportional to the field current and the voltage drop across it. In a typical alternator, the field current can be several amperes, leading to significant power dissipation. Ensure adequate heat sinking by using a large copper area on the PCB and consider a heatsink if the ambient temperature is high. The Multiwatt-15 package is designed for thermal performance, but proper layout is essential to keep the junction temperature within safe limits.
Place input and output capacitors close to the L9915 pins to ensure stability and filter electrical noise from the alternator. Use low-ESR capacitors with appropriate voltage ratings. The ground connection should be robust to minimize voltage drops. Follow the layout recommendations in the ST datasheet for optimal performance.
Do not exceed the maximum input voltage of 18V, as this can damage the regulator. Ensure the field winding is connected correctly to avoid reverse polarity. The warning lamp output should be connected to a suitable indicator lamp with a current-limiting resistor. Verify the pinout of the L9915-CB variant before substitution, as it may differ from the L9915.
Compliance Information
RoHS compliance is assumed based on STMicroelectronics' general compliance, but not explicitly stated in the provided data. AEC-Q100 is not applicable as this is an alternator regulator, not a standard IC.
