L9916 - Automotive Alternator Voltage Regulator | STMicroelectronics
MPN: L9916 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.25 | $3.25 |
| 10 | $2.95 | $29.50 |
| 100 | $2.65 | $265.00 |
| 500 | $2.4 | $1,200.00 |
| 1,000 | $2.2 | $2,200.00 |
L9916 Overview
A voltage regulator is an electronic circuit that maintains a constant output voltage despite variations in input voltage or load conditions. In automotive alternators, the regulator controls the field current to keep the battery voltage within a safe range (typically 13.5V to 14.5V). The L9916 belongs to the family of linear voltage regulators, specifically designed for high-temperature, high-vibration automotive environments. It integrates protection features such as overvoltage, overcurrent, and thermal shutdown, making it a robust choice for engine compartment mounting.
Key features of the L9916 include a wide operating temperature range of -40°C to +150°C, a maximum output current of , and a regulated output voltage of . It operates from an input voltage range of . The device uses a Darlington output stage to handle high field currents with low saturation voltage, improving efficiency and reducing heat dissipation. Its internal protection circuits guard against reverse battery, load dump, and over-temperature conditions, which are common in automotive electrical systems.
The L9916 is built using STMicroelectronics' proprietary BCD (Bipolar-CMOS-DMOS) technology, which combines high-voltage capability with low quiescent current. This technology enables the regulator to withstand transient voltages up to without damage. The device also features a soft-start function to limit inrush current during initial power-up, preventing stress on the alternator's field winding.
Typical applications include passenger car alternators, commercial vehicle charging systems, and industrial generators. In a standard alternator, the L9916 is connected between the battery sense line and the field coil, modulating the field current to maintain the target voltage. Its robust design ensures reliable operation in extreme temperatures and vibration levels found in engine compartments.
When designing with the L9916, ensure adequate heat sinking through the Multiwatt-15 package's exposed tab. The thermal resistance junction-to-case is , so a proper heatsink or PCB copper area is required for continuous operation at high output currents. Also, place a 100nF ceramic capacitor close to the supply pin for high-frequency decoupling.
Drop-in alternatives for L9916 — 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 L9916 (same form factor and footprint) — differing in Mounting Type, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
L9917
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
L9918
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
L9916 Maximum Ratings & Electrical Characteristics
| Output Type | Fixed |
| Operating Temperature Range | -40°C to +150°C |
| Package | Multiwatt-15 |
| Mounting Type | Through Hole |
| Protection Features | Overvoltage, Overcurrent, Thermal Shutdown, Reverse Battery |
| Technology | BCD (Bipolar-CMOS-DMOS) |
| RoHS Status | Compliant |
| AEC-Q100 Qualified | Yes |
| Lead-Free | Yes |
L9916 Pin Configuration
| Pin 1 | SUPPLY — Battery supply input |
| Pin 2 | GND — Ground |
| Pin 3 | OUTPUT — Field coil drive output |
| Pin 4 | SENSE — Battery voltage sense input |
| Pin 5 | NC — Not connected |
| Pin 6 | NC — Not connected |
| Pin 7 | NC — Not connected |
| Pin 8 | NC — Not connected |
| Pin 9 | NC — Not connected |
| Pin 10 | NC — Not connected |
| Pin 11 | NC — Not connected |
| Pin 12 | NC — Not connected |
| Pin 13 | NC — Not connected |
| Pin 14 | NC — Not connected |
| Pin 15 | TAB — Heatsink tab (connected to GND) |
Typical Applications
L9916 is suitable for 6 applications: Automotive Alternator Voltage Regulation, Commercial Vehicle Charging Systems, Industrial Generators, Marine Alternator Systems, Agricultural Equipment, Recreational Vehicles (RVs).
Automotive Alternator Voltage Regulation
The L9916 is specifically designed for automotive alternators to regulate the output voltage. It controls the field current to maintain battery voltage between 13.5V and 14.5V. The device's wide temperature range and protection features make it ideal for engine compartment mounting. In a typical alternator, the L9916 senses the battery voltage and adjusts the field coil current accordingly. It uses a Darlington output stage to handle high currents with low saturation voltage. The regulator's thermal shutdown prevents damage during overload conditions. Compared to discrete regulators, the L9916 offers integrated protection and higher reliability.
Recommended
Commercial Vehicle Charging Systems
In commercial vehicles, the L9916 ensures stable charging of 24V battery systems. It can handle the higher power demands of trucks and buses. The regulator's robust design withstands vibration and temperature extremes. It is often used in conjunction with a battery sense line to maintain accurate voltage. The L9916's overvoltage protection prevents damage to sensitive electronics. Its low quiescent current reduces battery drain when the engine is off. The Multiwatt-15 package allows for efficient heat dissipation in confined spaces.
Recommended
Industrial Generators
The L9916 can be used in industrial generators to regulate the output voltage. It provides reliable performance in harsh environments. The regulator's wide input voltage range accommodates varying generator speeds. Its thermal shutdown protects the generator from overheating. The L9916's reverse battery protection prevents damage from incorrect connections. It is suitable for both portable and stationary generators. The device's high current capability supports large field coils.
Recommended
Marine Alternator Systems
In marine applications, the L9916 regulates the alternator output for battery charging. It is resistant to corrosion and moisture. The regulator's wide temperature range handles engine room heat. Its protection features ensure safe operation in saltwater environments. The L9916's low dropout voltage improves charging efficiency. It is often used in sailboats and powerboats. The Multiwatt-15 package provides a secure mounting option.
Recommended
Agricultural Equipment
The L9916 is used in tractors and harvesters to regulate alternator output. It withstands dust, vibration, and temperature extremes. The regulator's robust design ensures long service life. Its overcurrent protection prevents damage to the field coil. The L9916's thermal shutdown prevents overheating in high-load conditions. It is compatible with various alternator types. The device's simple interface makes it easy to integrate.
Recommended
Recreational Vehicles (RVs)
In RVs, the L9916 regulates the alternator to charge house batteries. It provides stable voltage for sensitive electronics. The regulator's wide temperature range suits outdoor use. Its protection features prevent damage from voltage spikes. The L9916's low quiescent current reduces battery drain. It is ideal for motorhomes and trailers. The Multiwatt-15 package allows for easy mounting.
Recommended
Recommended Products Summary
Engineering reference data for L9916 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | L9917 | L9918 | TL431 |
|---|---|---|---|---|
| Package | Multiwatt-15 | Multiwatt-15 | Multiwatt-15 | TO-92 |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | Texas Instruments |
| 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 |
| Protection Features | Overvoltage, Overcurrent, Thermal Shutdown, Reverse Battery | Overvoltage, Overcurrent, Thermal Shutdown, Reverse Battery | Overvoltage, Overcurrent, Thermal Shutdown, Reverse Battery | None |
| Mounting Type | Through Hole | Through Hole | Through Hole | Through Hole |
Key Differentiators
- AEC-Q100 qualified for automotive use (vs TL431)
- Integrated protection features (vs TL431)
- Wide operating temperature range (vs TL431)
Design Notes
The L9916 in Multiwatt-15 package requires adequate heat sinking. The exposed tab should be soldered to a large copper area on the PCB. For continuous operation at high output currents, use a heatsink or forced air cooling. The thermal resistance junction-to-case is [DATA_NEEDED: thermal resistance], so calculate the junction temperature rise based on power dissipation.
Place a 100nF ceramic capacitor close to the SUPPLY pin for high-frequency decoupling. Use a 10uF electrolytic capacitor on the output to stabilize the regulator. Keep the SENSE trace short and away from noisy lines to avoid voltage sensing errors.
Do not exceed the maximum input voltage rating. Ensure the battery sense line is connected to the battery positive terminal, not the alternator output, to avoid regulation errors. The reverse battery protection is active only when the supply is connected correctly; verify polarity during installation.
Compliance Information
RoHS compliant and AEC-Q100 qualified per STMicroelectronics. Halogen-free status not specified in available data.
