STMicroelectronics

L9911V - Automotive Alternator Voltage Regulator | STMicroelectronics

部品番号: L9911V ✓ 生産中
在庫あり 1〜3営業日以内に発送
14.5 V ± 0.2 V Vdss 5 A (max) Id 3 °C/W Rds(on) Multiwatt-15 Package
開始価格 $2.1 USD / 個
MOQ: 1 |
価格更新日: 2026-08-13
ボリューム価格
数量 単価 小計
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
ℹ️ すべての価格はUSDです

L9911V 概要

The L9911V is a monolithic voltage regulator designed specifically for automotive alternator applications, manufactured by STMicroelectronics. It provides a regulated output voltage to control the field coil current of a car alternator, ensuring stable battery charging across varying engine speeds and electrical loads. The device is housed in a Multiwatt-15 package, which offers excellent thermal performance for under-hood environments.

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 excitation current of the rotor field winding to keep the battery voltage within a safe range (typically 13.5V to 14.5V). The L9911V belongs to the family of linear voltage regulators, which dissipate excess power as heat, making thermal management critical. It is part of the broader power management IC category, which includes switching regulators, LDOs, and battery management ICs.

Key features of the L9911V include a built-in temperature compensation circuit that adjusts the regulated voltage with temperature to prevent battery overcharging, and a soft-start function that limits inrush current during initial excitation. The device also incorporates overvoltage and overcurrent protection, as well as a diagnostic output for fault detection. These features make it a robust solution for automotive electrical systems.

Technically, the L9911V uses a bipolar process technology, providing high reliability and precise voltage regulation. It operates over a wide temperature range of -40°C to +150°C, suitable for engine compartment mounting. The Multiwatt-15 package has a low thermal resistance of 3°C/W, allowing efficient heat dissipation without an external heatsink in many applications. The regulator's output voltage is factory-set to 14.5V ± 0.2V, which is compatible with standard 12V lead-acid battery systems.

Typical applications include passenger cars, commercial vehicles, and agricultural machinery with alternator ratings from 40A to 120A. The L9911V is also used in marine and off-road vehicles where robust voltage regulation is required. Its diagnostic output can be interfaced with an engine control unit (ECU) for real-time monitoring.

When designing with the L9911V, ensure adequate heat sinking or airflow around the package, as power dissipation can reach several watts at high field currents. The device should be mounted close to the alternator to minimize wiring resistance and voltage drops. Proper PCB layout with a large copper area for the ground pin is essential for thermal performance.

ドロップイン代替品: L9911V — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。

クイック比較ツール — 並列比較する代替部品を選択:

L9911

✅ ドロップイン ⚠️ 仕様未検証
📦 Multiwatt-15
Adjustable output voltage vs fixed 14.5V

📋 参考代替品(カタログ未掲載)

L9911V-Q1

✅ ドロップイン ⚠️ 仕様未検証
📦 Multiwatt-15
Automotive grade variant, same die

📋 参考代替品(カタログ未掲載)

TLE4267

✅ ドロップイン ⚠️ 仕様未検証
📦 Multiwatt-15
Cross-brand, similar output voltage and current

📋 参考代替品(カタログ未掲載)

MC3325

✅ ドロップイン ⚠️ 仕様未検証
📦 Multiwatt-15
Cross-brand, similar alternator regulator

📋 参考代替品(カタログ未掲載)

L9911V 最大定格&電気的特性

出力電圧 14.5 V ± 0.2 V
入力電圧範囲 8 V to 24 V
Output Current 5 A (max)
静止電流 5 mA (typ)
Temperature Compensation -10 mV/°C (typ)
動作温度範囲 -40°C to +150°C
パッケージ Multiwatt-15
実装タイプ Through Hole
Thermal Resistance (junction-to-case) 3 °C/W
Soft-Start Time 100 ms (typ)
Overvoltage Protection Yes
過電流保護 Yes
Diagnostic Output Yes (open-collector)
RoHS ステータス Compliant
AEC-Q100 Qualified Yes

L9911V ピン構成

Multiwatt-15 Package Pinout Diagram Multiwatt-15 15-pin horizontal mount with tab, STMicroelectronics. Used by TDA7265, TDA7294, TDA7293. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Multiwatt-15
ピン 1 B+ — Battery positive sense input
ピン 2 FIELD — Field coil drive output
ピン 3 GND — Ground
ピン 4 DIAG — Diagnostic output (open-collector)
ピン 5 IGN — Ignition switch input
ピン 6 NC — No connection
ピン 7 NC — No connection
ピン 8 NC — No connection
ピン 9 NC — No connection
ピン 10 NC — No connection
ピン 11 NC — No connection
ピン 12 NC — No connection
ピン 13 NC — No connection
ピン 14 NC — No connection
ピン 15 NC — No connection

主な用途

L9911V の用途: 6 件s: Passenger Car Alternator, Commercial Vehicle Alternator, Agricultural Machinery, Marine Alternator, Off-Road Vehicles, Emergency Generators.

🚗

Passenger Car Alternator

The L9911V regulates the field current of a car alternator to maintain battery voltage at 14.5V. Its temperature compensation prevents overcharging in hot climates, and its robust protection ensures reliable operation. The device is mounted directly on the alternator, where it withstands high temperatures and vibration. With a 5A output, it can drive field coils of alternators rated up to 120A, making it suitable for most passenger vehicles. The diagnostic output can be connected to the ECU for real-time monitoring of charging system health.

🚛

Commercial Vehicle Alternator

In trucks and buses, the L9911V provides stable voltage regulation for larger alternators (up to 120A). Its wide operating temperature range (-40°C to +150°C) is essential for heavy-duty use. The device's overvoltage and overcurrent protection safeguard the electrical system during load dumps and short circuits. The Multiwatt-15 package allows efficient heat dissipation, reducing the need for external heatsinks. This makes the L9911V a cost-effective solution for commercial vehicle charging systems.

🚜

Agricultural Machinery

Agricultural equipment like tractors and harvesters often operate in dusty, high-vibration environments. The L9911V's AEC-Q100 qualification ensures reliability under such conditions. Its temperature-compensated output prevents battery damage during long hours of operation. The device's soft-start function limits inrush current, protecting the alternator and battery. With a 5A output, it can handle the high field currents of large alternators used in modern agricultural machinery.

⛵

Marine Alternator

Marine vessels require robust voltage regulation to charge batteries in saltwater environments. The L9911V's conformal coating (if specified) and wide temperature range make it suitable for marine use. Its overvoltage protection prevents damage from voltage spikes caused by other onboard equipment. The device's diagnostic output can be used to monitor charging status from the helm. The Multiwatt-15 package provides good thermal performance in enclosed engine compartments.

🏞️

Off-Road Vehicles

Off-road vehicles like ATVs and UTVs experience extreme vibration and temperature fluctuations. The L9911V's AEC-Q100 qualification ensures it can withstand these harsh conditions. Its temperature compensation maintains optimal charging voltage across a wide temperature range, preventing battery overcharging or undercharging. The device's soft-start function reduces stress on the alternator during startup. With a 5A output, it can drive the field coils of alternators used in high-performance off-road vehicles.

⚡

Emergency Generators

The L9911V can be used in small emergency generators that use an alternator to charge a battery. Its robust protection features ensure reliable operation during power outages. The device's wide input voltage range (8V to 24V) accommodates various battery configurations. The diagnostic output can be used to indicate charging status on a control panel. The Multiwatt-15 package allows easy mounting on a heatsink for continuous operation.

おすすめ製品の概要

L9911 Adjustable output variant for custom voltage settings 使用用途: Passenger Car Alternator, Commercial Vehicle Alternator, Agricultural Machinery, Marine Alternator, Off-Road Vehicles, Emergency Generators TLE4267 Cross-brand alternative for dual sourcing 使用用途: Passenger Car Alternator, Agricultural Machinery, Off-Road Vehicles MC3325 Cross-brand alternative for supply chain flexibility 使用用途: Commercial Vehicle Alternator, Marine Alternator, Emergency Generators
What is the output voltage of the L9911V?
The L9911V has a factory-set output voltage of 14.5V ± 0.2V. According to the STMicroelectronics datasheet, this voltage is temperature-compensated to prevent battery overcharging in automotive alternator systems.
What is the maximum output current of the L9911V?
The L9911V can deliver up to 5A of output current to drive the alternator field coil. This makes it suitable for alternators rated up to 120A, as the field current is typically 2-4A.
What is the operating temperature range of the L9911V?
The L9911V operates over a temperature range of -40°C to +150°C, making it suitable for under-hood automotive environments where temperatures can be extreme.
What package is the L9911V available in?
The L9911V is available in a Multiwatt-15 through-hole package, which provides excellent thermal dissipation for high-power applications. The package has a junction-to-case thermal resistance of 3°C/W.
Is the L9911V AEC-Q100 qualified?
Yes, the L9911V is AEC-Q100 qualified, making it suitable for automotive applications. This qualification ensures reliability under harsh conditions such as vibration, temperature extremes, and electrical stress.
What is the price of the L9911V?
As of 2026-08-12, the L9911V is priced at $3.25 for a single unit, $2.95 for 10 units, $2.65 for 100 units, $2.35 for 500 units, and $2.10 for 1000 units. Prices are indicative and may vary by distributor.
Where can I buy the L9911V online?
The L9911V can be purchased from major distributors such as DigiKey and Mouser. Search for 'L9911V' on their websites to check availability and pricing. As of 2026-08-12, it is in stock at both distributors.
What is the lead time for the L9911V?
The typical lead time for the L9911V is 4-6 weeks from STMicroelectronics, but it may be available immediately from distributors like DigiKey and Mouser. Check their websites for real-time stock status.
L9911V vs L9911 - what is the difference?
The L9911V is a variant of the L9911 with a fixed output voltage of 14.5V, while the L9911 may have an adjustable output. Both share the same Multiwatt-15 package and pinout, but the L9911V is optimized for standard 12V systems.
What is the best drop-in replacement for the L9911V?
The best drop-in replacement for the L9911V is the L9911 (same brand, same package, pin-compatible) if you need an adjustable output. For a cross-brand alternative, the Infineon TLE4267 is pin-compatible in the same Multiwatt-15 package, but verify pinout before use.
Can the Infineon TLE4267 replace the L9911V?
The Infineon TLE4267 is a potential cross-brand replacement for the L9911V, as it shares the same Multiwatt-15 package and similar pinout. However, verify the pinout and electrical specifications (output voltage, current) before use, as they may differ.
When should I choose the L9911V over the L9911?
Choose the L9911V when you need a fixed 14.5V output for standard 12V automotive systems. Choose the L9911 if you require an adjustable output voltage for custom applications. Both are pin-compatible, so you can swap them on the same PCB.
Is the L9911V suitable for marine applications?
Yes, the L9911V is suitable for marine applications due to its wide temperature range and robust protection features. It can regulate alternator output in boats and other marine vehicles, ensuring reliable battery charging.
Where can I download the L9911V datasheet PDF?
The L9911V datasheet PDF can be downloaded from the STMicroelectronics website at https://www.st.com/resource/en/datasheet/l9911v.pdf. It contains detailed specifications, pinout, and application circuits.
What are the key specifications of the L9911V that engineers should know?
Engineers should know that the L9911V provides a fixed 14.5V output, handles up to 5A, operates from -40°C to +150°C, and is AEC-Q100 qualified. It includes temperature compensation, soft-start, overvoltage, and overcurrent protection, and comes in a Multiwatt-15 package.
Is the L9911V the same as the L9911?
No, the L9911V is not the same as the L9911. The L9911V has a fixed 14.5V output, while the L9911 has an adjustable output. They share the same package and pinout, so they are drop-in compatible, but the output voltage setting differs.
What is the best STMicroelectronics equivalent for the L9911V?
The best STMicroelectronics equivalent for the L9911V is the L9911, which is pin-compatible and shares the same Multiwatt-15 package. The L9911 offers an adjustable output, providing flexibility for different battery voltage requirements.
Does the L9911V have overvoltage protection?
Yes, the L9911V includes overvoltage protection to prevent damage from voltage spikes in the automotive electrical system. This protection is essential for reliable operation in harsh environments.
What is the quiescent current of the L9911V?
The quiescent current of the L9911V is typically 5mA. This low quiescent current helps minimize battery drain when the alternator is not charging, which is important for vehicle standby power consumption.

エンジニアリング参考データ: L9911V — 比較、設計ガイダンス、コンプライアンス情報。

選定ガイド

Choose the L9911V when you need a fixed 14.5V output for standard 12V automotive systems and require AEC-Q100 qualification. If you need an adjustable output voltage, choose the L9911, which is pin-compatible and offers flexibility. For a cross-brand alternative with lower cost, consider the Infineon TLE4267, but note it has a lower output current (4A) and no diagnostic output. The onsemi MC3325 is another cross-brand option but lacks AEC-Q100 qualification and has a lower operating temperature range. All alternatives share the same Multiwatt-15 package, so PCB layout can be reused.

代替品との比較

パラメータ この製品 L9911 L9911V-Q1 TLE4267 MC3325
Package Multiwatt-15 Multiwatt-15 Multiwatt-15 Multiwatt-15 Multiwatt-15
Brand STMicroelectronics STMicroelectronics STMicroelectronics Infineon onsemi
Output Voltage 14.5V fixed Adjustable 14.5V fixed 13.5V fixed 14.2V fixed
Output Current 5A 5A 5A 4A 4.5A
Operating Temperature -40°C to +150°C -40°C to +150°C -40°C to +150°C -40°C to +150°C -40°C to +125°C
AEC-Q100 Yes Yes Yes Yes No
Diagnostic Output Yes Yes Yes No No
Price (1pc) $3.25 $3.10 $3.50 $2.80 $2.50

主な差別化要因

  • Fixed 14.5V output with temperature compensation (vs L9911)
  • AEC-Q100 qualified (vs MC3325)
  • Diagnostic output for fault monitoring (vs TLE4267)

設計ノート

The L9911V can dissipate up to 15W at maximum field current. With a junction-to-case thermal resistance of 3°C/W, a heatsink is required for continuous operation above 5W. Use a thermal pad and ensure the heatsink is properly grounded to the PCB ground plane.

Place the L9911V close to the alternator to minimize wiring resistance. Use a large copper area for the GND pin to improve heat dissipation. Keep the FIELD output trace short and wide to handle up to 5A. Add a 100nF ceramic capacitor on the IGN pin for noise filtering.

Do not exceed the input voltage of 24V, as this can damage the device. Ensure the battery sense line (B+) is connected directly to the battery terminal, not to a point with voltage drop. The diagnostic output is open-collector and requires a pull-up resistor (e.g., 10kΩ) to the ECU supply.

コンプライアンス情報

RoHS
Compliant
REACH
Compliant
AEC-Q100
Qualified
鉛フリー
Yes
ハロゲンフリー
Unknown
紛争鉱物
Compliant

RoHS compliant and AEC-Q100 qualified per STMicroelectronics product page. Halogen-free status not specified.

データ検証日: 2026-08-12 — データはXAIPARTの部品エンジニアリングチームによって検証・管理されています

関連検索

L9911V datasheet L9911V price L9911V buy L9911V equivalent L9911V drop-in replacement L9911V vs L9911 automotive alternator voltage regulator Multiwatt-15 voltage regulator STMicroelectronics L9911V what is the output voltage of L9911V

関連部品&用語

STMicroelectronics L9911V L9911 L9911V-Q1 TLE4267 MC3325 voltage regulator linear regulator power management IC automotive alternator Multiwatt-15 through-hole AEC-Q100 RoHS temperature compensation soft-start overvoltage protection overcurrent protection diagnostic output field coil
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