L9915 - Automotive Alternator Voltage Regulator | STMicroelectronics
MPN: L9915 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.25 | $3.25 |
| 10 | $2.95 | $29.50 |
| 100 | $2.65 | $265.00 |
| 500 | $2.35 | $1,175.00 |
| 1,000 | $2.1 | $2,100.00 |
Drop-in alternatives for L9915 — 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:
L9910
✅ Drop-In📋 Reference alternative (not in catalog)
L9915-Q1
✅ Drop-In📋 Reference alternative (not in catalog)
L9915
✅ Drop-In✓ 99,999 In Stock
$2.1 / Unit
View Datasheet →L9915 Maximum Ratings & Electrical Characteristics
| Output Voltage | 14.5 V |
| Input Voltage Range | 8 V to 28 V |
| Output Current | 5 A |
| Dropout Voltage | 1.5 V at 5 A |
| Quiescent Current | 10 mA |
| Operating Temperature Range | -40°C to +150°C |
| Package | Multiwatt-15 |
| Mounting Type | Through Hole |
| Thermal Resistance (junction-to-case) | 3 °C/W |
| Line Regulation | 10 mV |
| Load Regulation | 20 mV |
| Protection Features | Overvoltage, Overcurrent, Thermal Shutdown |
| RoHS Status | Compliant |
| AEC-Q100 Qualified | Yes |
| Lead-Free | Yes |
L9915 Pin Configuration
| Pin 1 | B+ — Battery positive sense input |
| Pin 2 | FIELD — Field coil driver output |
| Pin 3 | GND — Ground |
| Pin 4 | IGN — Ignition switch input |
| Pin 5 | LAMP — Charge indicator lamp output |
| Pin 6 | B+ — Battery positive sense input |
| Pin 7 | FIELD — Field coil driver output |
| Pin 8 | GND — Ground |
| Pin 9 | IGN — Ignition switch input |
| Pin 10 | LAMP — Charge indicator lamp output |
| Pin 11 | B+ — Battery positive sense input |
| Pin 12 | FIELD — Field coil driver output |
| Pin 13 | GND — Ground |
| Pin 14 | IGN — Ignition switch input |
| Pin 15 | LAMP — Charge indicator lamp output |
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: Automotive Alternator Voltage Regulation, Marine Battery Charging Systems, Agricultural Vehicle Electrical Systems, Off-Road Vehicle Power Management, Truck and Bus Charging Systems, Industrial Engine Generators.
Automotive Alternator Voltage Regulation
The L9915 is specifically designed for automotive alternator voltage regulation. It maintains the battery voltage at 14.5V by controlling the field current of the alternator. The device's wide input voltage range (8V to 28V) and high output current (5A) make it ideal for handling the varying electrical loads in a vehicle. Its AEC-Q100 qualification ensures reliability in harsh automotive environments, and its protection features (overvoltage, overcurrent, thermal shutdown) safeguard the alternator and battery from damage. In a typical application, the L9915 is connected between the battery and the field coil, with the regulator sensing the battery voltage and adjusting the field current to keep it within the target range. The Multiwatt-15 package with its low thermal resistance (3°C/W) allows efficient heat dissipation, ensuring stable operation even at high ambient temperatures under the hood.
Recommended
Marine Battery Charging Systems
In marine applications, the L9915 regulates the charging voltage of the battery bank, ensuring it stays at 14.5V to prevent overcharging and extend battery life. The device's wide operating temperature range (-40°C to +150°C) and corrosion-resistant packaging make it suitable for the saltwater environment. The L9915's high output current (5A) can handle the demands of multiple batteries and onboard electronics. The regulator's protection features prevent damage from voltage spikes and overloads, which are common in marine electrical systems. The Multiwatt-15 package allows for easy mounting on a heatsink, which is essential for dissipating the heat generated during continuous operation. The L9915's robust design ensures reliable performance in the harsh marine environment, making it a preferred choice for boat builders and marine electronics manufacturers.
Recommended
Agricultural Vehicle Electrical Systems
Agricultural vehicles such as tractors and harvesters rely on the L9915 to maintain a stable battery voltage for their electrical systems, including lights, sensors, and control units. The device's wide input voltage range (8V to 28V) accommodates the voltage fluctuations caused by varying engine speeds and heavy electrical loads. The L9915's high output current (5A) ensures sufficient field current for the alternator, even when multiple accessories are in use. Its rugged construction and wide operating temperature range (-40°C to +150°C) make it suitable for the dusty and vibration-prone environment of agricultural machinery. The regulator's protection features prevent damage from overvoltage and overcurrent conditions, which can occur during sudden load changes. The Multiwatt-15 package provides excellent thermal performance, allowing the device to operate reliably in the high ambient temperatures often found in engine compartments.
Recommended
Off-Road Vehicle Power Management
Off-road vehicles, including ATVs and utility vehicles, use the L9915 to regulate the charging voltage of their batteries, ensuring reliable starting and operation in remote locations. The device's wide input voltage range (8V to 28V) and high output current (5A) make it suitable for the demanding electrical loads of off-road vehicles, such as winches and auxiliary lighting. The L9915's protection features (overvoltage, overcurrent, thermal shutdown) protect the battery and electrical system from damage caused by voltage spikes and overloads, which are common in off-road environments. The device's wide operating temperature range (-40°C to +150°C) ensures reliable performance in extreme weather conditions, from freezing winters to scorching summers. The Multiwatt-15 package allows for easy mounting on a heatsink, which is essential for dissipating the heat generated during continuous operation. The L9915's robust design makes it a trusted choice for off-road vehicle manufacturers.
Recommended
Truck and Bus Charging Systems
In trucks and buses, the L9915 regulates the alternator output to maintain a stable battery voltage, which is critical for the operation of lights, air conditioning, and other electrical systems. The device's high output current (5A) can handle the large field currents required by heavy-duty alternators. The L9915's wide input voltage range (8V to 28V) accommodates the voltage variations caused by engine speed changes and electrical load fluctuations. Its AEC-Q100 qualification ensures reliability in the demanding commercial vehicle environment, where the regulator is subjected to vibration, temperature extremes, and electrical noise. The protection features of the L9915 prevent damage from overvoltage and overcurrent conditions, which can occur during jump starts or load dumps. The Multiwatt-15 package provides excellent thermal performance, allowing the device to operate reliably in the high ambient temperatures found in engine compartments.
Recommended
Industrial Engine Generators
The L9915 is used in industrial engine generators to regulate the voltage of the battery charging system, ensuring reliable starting and operation of the generator. The device's wide input voltage range (8V to 28V) and high output current (5A) make it suitable for the demanding electrical loads of industrial generators, such as control panels and electric starters. The L9915's protection features (overvoltage, overcurrent, thermal shutdown) protect the battery and electrical system from damage caused by voltage spikes and overloads, which are common in industrial environments. The device's wide operating temperature range (-40°C to +150°C) ensures reliable performance in harsh industrial conditions, including high temperatures and vibration. The Multiwatt-15 package allows for easy mounting on a heatsink, which is essential for dissipating the heat generated during continuous operation. The L9915's robust design makes it a reliable choice for industrial generator manufacturers.
Recommended
Recommended Products Summary
Engineering reference data for L9915 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | L9910 | L9915-Q1 | LM2941 |
|---|---|---|---|---|
| Package | Multiwatt-15 | Multiwatt-15 | Multiwatt-15 | TO-220 |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | Texas Instruments |
| Output Voltage | 14.5V | 14.5V | 14.5V | Adjustable (1.2V to 26V) |
| Output Current | 5A | 3A | 5A | 1A |
| Input Voltage Range | 8V to 28V | 8V to 24V | 8V to 28V | 4.5V to 26V |
| Dropout Voltage | 1.5V at 5A | 1.2V at 3A | 1.5V at 5A | 0.5V at 1A |
| Operating Temperature Range | -40°C to +150°C | -40°C to +150°C | -40°C to +150°C | -40°C to +125°C |
| AEC-Q100 Qualified | Yes | Yes | Yes | No |
Key Differentiators
- Higher output current (5A) compared to L9910 (vs L9910)
- Wider input voltage range (8V to 28V) compared to L9910 (vs L9910)
- AEC-Q100 qualified, unlike LM2941 (vs LM2941)
Design Notes
The L9915 can dissipate significant power when the input voltage is high and the output current is high. For example, at VIN=28V, VOUT=14.5V, and IOUT=5A, the power dissipation is (28-14.5)*5 = 67.5W. With a junction-to-case thermal resistance of 3°C/W, the junction temperature rise is 202.5°C above the case temperature. A proper heatsink with a thermal resistance of less than 1°C/W is required to keep the junction temperature below 150°C. Ensure the heatsink is properly attached to the metal tab of the Multiwatt-15 package.
Place input and output capacitors close to the L9915 pins to minimize parasitic inductance and ensure stability. Use a 100uF electrolytic capacitor on the input and a 100uF electrolytic capacitor on the output, with a 0.1uF ceramic capacitor in parallel for high-frequency noise filtering. The ground connection should be a low-impedance path to the battery negative terminal to avoid ground bounce.
Do not exceed the maximum input voltage of 28V, as this can damage the regulator. Ensure the ignition switch input (IGN) is properly connected to the vehicle's ignition system to enable the regulator only when the engine is running. The charge indicator lamp output (LAMP) should be connected to a lamp with a current rating of at least 100mA to avoid false indications. Use a flyback diode across the field coil to protect the regulator from inductive voltage spikes.
Compliance Information
RoHS compliant and AEC-Q100 qualified per STMicroelectronics datasheet. Halogen-free status not specified.
