L9914A - Automotive Alternator Voltage Regulator | STMicroelectronics
Référence : L9914A ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $2.85 | $2,85 |
| 10 | $2.56 | $25,60 |
| 100 | $2.28 | $228,00 |
| 500 | $2.05 | $1 025,00 |
| 1 000 | $1.82 | $1 820,00 |
L9914A Présentation
A voltage regulator is an electronic circuit that maintains a constant output voltage despite variations in input voltage and load current. In automotive alternators, the regulator controls the field coil current to keep the battery voltage within a safe range, typically around 14V, ensuring proper charging and preventing overvoltage damage to sensitive electronics. The L9914A belongs to the family of linear voltage regulators, which are essential in power management systems for vehicles, bridging the gap between the raw alternator output and the stable voltage required by the battery and electrical loads.
Key features of the L9914A include a precise 14.2V output voltage with ±1% tolerance, a low dropout voltage of 1.5V at full load, and an integrated temperature-compensated reference. The device also incorporates overvoltage and overcurrent protection, as well as thermal shutdown, ensuring reliable operation under harsh automotive conditions. Its PowerSO-8 package offers excellent thermal performance, with a thermal resistance of 50°C/W, allowing it to dissipate up to 2W without external heatsinking in typical alternator environments.
The L9914A utilizes a bipolar junction transistor (BJT) as the pass element, providing robust current handling and low saturation voltage. The internal reference is based on a bandgap circuit, which maintains output voltage accuracy across the -40°C to +150°C junction temperature range. The device is designed to withstand load dump transients up to 40V, making it suitable for direct connection to the alternator output without additional external clamping components.
Typical applications include automotive alternators for passenger cars, light trucks, and commercial vehicles, as well as industrial generators and battery charging systems. The L9914A is also used in marine and off-road vehicles where robust voltage regulation is critical. Its wide operating temperature range and protection features make it a reliable choice for under-hood environments.
When designing with the L9914A, ensure adequate PCB copper area for heat dissipation, especially at high output currents. The device requires a minimum input capacitance of 100nF for stability, and the output should be bypassed with a 10µF capacitor to filter ripple. Proper grounding and short leads are essential to minimize parasitic inductance and ensure stable operation.
Alternatives de remplacement direct pour L9914A — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
L9914
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
L9914B
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
TLE4267
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
NCV4275
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
L9914A Valeurs maximales et caractéristiques électriques
| Tension de sortie | 14.2 V ±1% |
| Plage de tension d'entrée | 8 V to 28 V |
| Courant de sortie maximal | 150 mA |
| Tension de déchet | 1.5 V at 150 mA |
| Courant de repos | 5 mA |
| Load Regulation | ±0.5% |
| Line Regulation | ±0.2% |
| Plage de température de fonctionnement | -40°C to +150°C |
| Storage Temperature Range | -55°C to +150°C |
| Thermal Resistance (θJA) | 50 °C/W |
| Boîtier | PowerSO-8 |
| Type de montage | Surface Mount |
| Niveau MSL | 3 (168 hours) |
| Statut RoHS | Compliant |
| AEC-Q100 | Qualified |
Configuration des broches de L9914A
| Broche 1 | OUT — Regulated output voltage (14.2V) |
| Broche 2 | GND — Ground |
| Broche 3 | SENSE — Voltage sense input for regulation |
| Broche 4 | BAT_SENSE — Battery voltage sense |
| Broche 5 | FIELD — Field coil driver output |
| Broche 6 | LAMP — Lamp driver output for charging indicator |
| Broche 7 | IGN — Ignition input |
| Broche 8 | IN — Input voltage from alternator |
Applications typiques
L9914A convient pour 6 applications: Automotive Alternator, Industrial Generator, Marine and Off-Road Vehicles, Battery Charging Systems, Heavy-Duty Trucks, Agricultural Equipment.
Automotive Alternator
The L9914A is specifically designed for automotive alternator voltage regulation. It maintains the battery voltage at 14.2V by controlling the field coil current, ensuring proper charging and preventing overvoltage. The device's wide input range (8V-28V) accommodates alternator output variations with engine speed, while its AEC-Q100 qualification and -40°C to +150°C operating range ensure reliability in under-hood environments. The integrated overvoltage protection handles load dump transients up to 40V, protecting the regulator and downstream electronics. In a typical alternator, the L9914A is connected between the battery sense line and the field coil, with the output driving the field driver transistor. The sense input monitors battery voltage, and the regulator adjusts the field current to maintain the target voltage. The lamp driver output can be used to indicate charging status. Performance considerations include thermal management: at 150mA output and 14.2V drop, power dissipation is approximately 2.1W, requiring adequate PCB copper area or a heatsink to keep junction temperature below 150°C.
Recommandé
Industrial Generator
The L9914A is suitable for industrial generators that require a stable 14.2V output for battery charging. Its robust protection features, including overvoltage, overcurrent, and thermal shutdown, make it reliable in harsh environments. The device can operate from a wide input range, accommodating generator output fluctuations. In a generator application, the L9914A is used to regulate the excitation current of the generator's field winding, ensuring a constant output voltage. The sense input is connected to the battery or load, and the regulator adjusts the field current accordingly. The device's low quiescent current (5mA) minimizes standby power consumption. Performance considerations include the need for proper heat sinking, as the device may dissipate significant power at high output currents. The PowerSO-8 package with exposed pad facilitates heat transfer to the PCB.
Recommandé
Marine and Off-Road Vehicles
The L9914A is ideal for marine and off-road vehicles where robust voltage regulation is critical. Its wide operating temperature range and protection features ensure reliable operation in extreme conditions. The device is AEC-Q100 qualified, making it suitable for automotive-grade applications. In marine applications, the L9914A regulates the alternator output to charge the battery bank, providing a stable 14.2V supply for navigation and communication equipment. The device's overvoltage protection is essential for handling load dump transients caused by disconnecting the battery while the engine is running. The lamp driver output can be used to indicate charging status on the dashboard. Performance considerations include corrosion resistance, which is addressed by the device's conformal coating option (available on request).
Recommandé
Battery Charging Systems
The L9914A can be used in battery charging systems to maintain a constant voltage for lead-acid batteries. Its 14.2V output is ideal for 12V battery charging, and the device's precision ensures optimal charging without overcharging. The regulator's low dropout voltage (1.5V) allows efficient operation even when the input voltage is close to the output. In a battery charger, the L9914A is used as a linear regulator to provide a stable charging voltage. The input is connected to a rectified AC source or a DC-DC converter, and the output is connected to the battery. The sense input monitors the battery voltage, and the regulator adjusts the output to maintain the target voltage. The device's thermal shutdown protects against overheating during prolonged charging. Performance considerations include power dissipation, which can be significant at high charging currents; a heatsink is recommended for currents above 100mA.
Recommandé
Heavy-Duty Trucks
The L9914A is used in heavy-duty trucks for alternator voltage regulation, ensuring reliable charging of the 24V battery system (when used in a 12V configuration). Its robust design and wide temperature range make it suitable for the demanding conditions of commercial vehicles. The device's overvoltage protection is critical for handling load dump transients in trucks with high electrical loads. In a truck alternator, the L9914A regulates the field current to maintain the battery voltage at 14.2V. The device's low quiescent current helps reduce battery drain when the engine is off. The lamp driver output can be used to indicate charging status on the dashboard. Performance considerations include the need for adequate heat dissipation, as the device may operate at high ambient temperatures under the hood.
Recommandé
Agricultural Equipment
The L9914A is suitable for agricultural equipment such as tractors and harvesters, where reliable voltage regulation is essential for electronic controls and lighting. Its wide input range and protection features ensure operation in dusty and harsh environments. The device's AEC-Q100 qualification guarantees reliability in automotive-grade applications. In agricultural equipment, the L9914A regulates the alternator output to charge the battery and power the electrical system. The device's overvoltage protection prevents damage from load dump transients caused by disconnecting the battery. The lamp driver output can be used to indicate charging status. Performance considerations include the need for a sealed enclosure or conformal coating to protect against dust and moisture.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour L9914A — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | L9914 | L9914B | TLE4267 | NCV4275 |
|---|---|---|---|---|---|
| Package | PowerSO-8 | PowerSO-8 | PowerSO-8 | SO-8 | SO-8 |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | Infineon | onsemi |
| Output Voltage | 14.2V ±1% | 14.2V ±2% | 14.2V ±1% | 5V ±2% | 5V ±2% |
| Output Current | 150mA | 150mA | 150mA | 400mA | 450mA |
| Dropout Voltage | 1.5V | 1.5V | 1.5V | 0.5V | 0.6V |
| Quiescent Current | 5mA | 5mA | 5mA | 0.2mA | 0.2mA |
| Operating Temperature | -40°C to +150°C | -40°C to +125°C | -40°C to +150°C | -40°C to +150°C | -40°C to +150°C |
| AEC-Q100 | Qualified | Qualified | Qualified | Qualified | Qualified |
Principaux différenciateurs
- Precision output voltage of 14.2V ±1% (vs L9914)
- Wider operating temperature range of -40°C to +150°C (vs L9914)
- AEC-Q100 qualified for automotive (vs TLE4267)
Notes de conception
The L9914A can dissipate up to 2W in typical alternator applications. With a thermal resistance of 50°C/W, the junction temperature rise is 100°C above ambient. Ensure adequate PCB copper area (at least 1 square inch) connected to the exposed pad to keep the junction temperature below 150°C. For high ambient temperatures, consider adding a heatsink or forced airflow.
Place a 100nF ceramic capacitor close to the input pin (pin 8) and a 10µF electrolytic capacitor on the output (pin 1) to ensure stability and filter ripple. The sense input (pin 3) should be connected directly to the battery positive terminal using a separate trace to avoid voltage drops in the power path. Keep the ground connection short and use a star-ground topology to minimize noise.
Do not exceed the maximum input voltage of 28V (40V transient). Ensure the battery sense line is fused to protect against short circuits. The lamp driver output (pin 6) is an open-collector output and requires an external pull-up resistor to the battery voltage. Avoid running the field driver (pin 5) without a flyback diode across the field coil to prevent inductive spikes.
Informations de conformité
RoHS compliant and AEC-Q100 qualified per STMicroelectronics product page. Halogen-free per datasheet.
