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STMicroelectronics L9914A
- Part No.:
- L9914A
- Manufacturer:
- STMicroelectronics
- Category:
- Special Purpose Regulators
- Package:
- Multiwatt-8 (Straight Leads)
- Datasheet:
-
L9914A.pdf
- Description:
- IC REG AUTO APPL 1OUT 8MULTIWATT
- Quantity:
- Payment:
- Shipping:
Inventory:2,833
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Product details
Overview
L9914A from STMicroelectronics is an AEC-Q100 qualified automotive high-side field driver voltage regulator for alternator control. It regulates generator output via variable-frequency PWM-driven field current, accepts setpoint commands via RVC protocol from the ECU, and features LRC load response control with 2.5 s ramp rate. Used in 12 V automotive charging systems with thermal and overvoltage protection.
For engineers reviewing the L9914A datasheet, L9914A pinout, L9914A application, or L9914A equivalent, key selection criteria include RVC interface compatibility, field driver saturation voltage (≤750 mV at 9 A), thermal shutdown threshold (175 ±15 °C), and Multiwatt8 package integration into engine bay PCB layouts.
Technical Context
The L9914A implements closed-loop generator regulation by sensing phase voltage (P pin) and generator output (VGO), dynamically adjusting field duty cycle via high-side F-driver based on RVC-set target voltage. Its regulation logic includes initiation frequency detection (fIFR = 61–83 Hz) and fault latching with 0.935–1.265 s delay before L-terminal warning activation.
Diagnostic functions include overvoltage detection (VOV = 16.5–22 V), phase-loss response (VP2 = 7–9 V threshold), and load-speed compensation - with dedicated LRC timing (2.125–5.75 s) and field strobe duty factor (13.5% at power-up) to stabilize output during transient load steps.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating supply voltage | 8–16 V - powers device from generator output (VGO); supports full automotive battery range including cold-crank dips. |
| Field output saturation voltage | ≤750 mV @ 9 A, Tcase ≤ 25 °C - minimizes conduction loss and thermal stress in high-current field path. |
| Load response control (LRC) rate | 2.125–5.75 s - defines time to ramp field duty from 0% to 100% during load increase; ensures stable bus voltage without overshoot. |
| Thermal shutdown threshold | 175 ±15 °C - protects silicon during sustained overload or poor heatsinking; enables safe recovery after cooling. |
| RVC protocol interface | ECM-controlled PWM input on L pin - allows dynamic setpoint adjustment (e.g., eco-mode voltage reduction or battery temperature compensation). |
| Phase sense threshold (VP2) | 7–9 V - detects stator phase presence for fault diagnosis; triggers field hold if phase drops below threshold while VGO > setpoint. |
| Overvoltage protection (VOV) | 16.5–22 V - disables minimum field duty cycle above threshold to prevent battery overcharge and component damage. |
Pinout & Package
Package: Multiwatt8 (pin 5 = GND), thermally enhanced through-hole package with exposed metal tab for heatsink mounting; RoHS-compliant ECOPACK® grade.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 P | Phase sense input | Monitors stator AC phase voltage to detect rotation speed and initiate regulation; sinking current threshold VP2 = 7–9 V. |
| 2 FM | Field monitor output | Open-collector diagnostic signal reflecting field current status; used for ECM feedback and fault correlation. |
| 3 RESERVED | Reserved | Must be connected to GND per datasheet; no internal connection - prevents floating node noise coupling. |
| 4 L | RVC command input / warning output | Accepts 128 Hz PWM from ECU for setpoint control; switches to 0–1.55 V fault signaling when faults persist > 0.935 s. |
| 5 GND | Power and signal ground | Common reference for all analog and digital circuitry; pin 5 is designated GND in Multiwatt8 mechanical layout. |
| 6 RESERVED | Reserved | Must be connected to GND per datasheet; unused internal bond pad - ensures mechanical and thermal symmetry. |
| 7 F | High-side field driver output | Drives alternator rotor winding; rated for 9 A short-circuit limit at 25 °C; integrates flyback diode (VF ≤ 1.85 V). |
| 8 VGO | Generator output sense & supply | Provides operating power and senses regulated battery voltage; operates from 8–18 V; enables reverse-battery tolerance down to –2.5 V. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 qualification | Qualified for automotive Grade 0 (–40 to +150 °C junction), enabling deployment in engine compartment environments without derating. |
| Integrated field discharge rectifier | On-chip flyback diode (VF ≤ 1.85 V @ 6 A) eliminates external snubber, reducing BOM count and PCB area in alternator control modules. |
| Complex diagnostics with delay filtering | Configurable fault latching (TDELAY = 0.935–1.265 s) prevents false warnings from transient noise or brief phase dropouts. |
| Load and speed regulation compensation | Simultaneous correction for load step (LRC) and RPM variation (VSR ≤ 100 mV) maintains ±300 mV total regulation accuracy across operating range. |
| RVC protocol interface | Dedicated L-pin PWM input enables real-time voltage setpoint updates from ECU - supporting start-stop, battery health, and thermal management strategies. |
Applications
| Engine Start-Stop Systems | 12 V Automotive Charging Control |
|---|---|
|
Use Scenario: Vehicle restarts engine after idle stop; alternator must rapidly restore battery charge without voltage spikes or ECU reset. IC Role / Device Role / Timing Role: High-side field driver regulating rotor current via RVC-set voltage; initiates field ramp within 2.5 s of restart command. Use Value: LRC rate ensures controlled 0–100% field duty transition, limiting bus voltage overshoot to <300 mV during load recovery. |
Use Scenario: Continuous regulation of 12 V battery voltage across engine speeds (2,000–10,000 rpm) and loads (10–95% capacity). IC Role / Device Role / Timing Role: Closed-loop generator controller using P-phase sensing and VGO feedback; adjusts field PWM frequency (61–83 Hz) and duty cycle. Use Value: Speed regulation error ≤100 mV and load regulation ≤300 mV maintain stable power for ADAS, infotainment, and body electronics. |
| Thermally Constrained Engine Bay Layouts | Diagnostic-Enabled Battery Management |
|
Use Scenario: Compact alternator control module mounted near hot exhaust components with limited airflow and heatsink mass. IC Role / Device Role / Timing Role: Thermal-protection IC with 175 ±15 °C shutdown and 1.5 °C/W junction-to-case resistance; enables safe operation up to 150 °C ambient. Use Value: Integrated thermal shutdown and field current limiting (6–9 A) prevent thermal runaway without external sensors or protection circuitry. |
Use Scenario: ECU monitors alternator health via FM pin and L-terminal fault pulses to detect open-field, short-field, or phase-loss conditions. IC Role / Device Role / Timing Role: Diagnostic hub generating standardized fault signatures (e.g., 1.1 s L-pulse for overvoltage) for CAN-based vehicle diagnostics. Use Value: Fault delay filtering and multi-condition latching (e.g., VP2 + VGO > setpoint) reduce false DTCs and improve OBD-II compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar automotive alternator field driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3495MTCX/NOPB | Non-AEC-Q100 DC/DC controller; requires external MOSFET and discrete protection; no RVC interface or integrated diagnostics. | Designed for generic buck regulation, not alternator-specific phase sensing or LRC timing. | Select only for non-automotive or prototype use where AEC-Q100, diagnostics, and RVC are unnecessary. |
| UC3906N | Legacy battery charger IC; lacks high-side field drive, phase sensing, and automotive temp range; no thermal shutdown or overvoltage protection. | Targeted at lead-acid battery chargers, not generator regulation in running vehicles. | Not suitable for OEM alternator control; consider only for educational or low-volume legacy repair contexts. |
Compared with LM3495MTCX/NOPB and UC3906N, the L9914A delivers integrated AEC-Q100 reliability, RVC protocol support, and alternator-specific regulation logic - eliminating need for external phase detection, fault filtering, and field driver components required by generic controllers.
Availability
L9914A is available at Aetrix Electronics and suitable for engine control units, start-stop modules, and 12 V automotive charging systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for L9914A includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power ICs, and automotive-grade analog devices since 1987.
The L9914A belongs to ST's automotive power management portfolio, engineered specifically for intelligent alternator control - integrating regulation, diagnostics, and protection in a single AEC-Q100 qualified device for modern vehicle electrical architectures.
FAQ
What is the purpose of the L terminal on the L9914A?
The L terminal serves dual functions: as an input for RVC protocol PWM signals from the ECU to set generator voltage, and as an open-drain diagnostic output that pulses low during detected faults (e.g., overvoltage or phase loss). Its 128 Hz PWM acceptance and 0–1.55 V saturation enable bidirectional communication without additional level-shifting circuitry.
How does the L9914A handle phase loss detection?
The L9914A continuously monitors phase voltage at the P pin. If the sensed voltage falls below VP2 (7–9 V) while VGO remains above the setpoint, it activates a 31.25% field strobe to maintain minimal excitation and prevent rotor demagnetization. This behavior is latched only after confirming the condition persists beyond the 0.935–1.265 s fault delay window.
Can the L9914A operate without a battery connected?
Yes - the L9914A supports no-battery operation with VGO regulated between VS−2 V and VS+2 V at 2–50% load. Its internal design tolerates open-battery conditions during cranking or fault scenarios, maintaining field control and diagnostics while preventing unregulated generator output from damaging downstream electronics.
What thermal considerations apply to the Multiwatt8 package?
The Multiwatt8 package features an exposed metal tab (pin 5 GND) designed for direct heatsink attachment. With Rth j-case = 1.5 °C/W, achieving Tj ≤ 150 °C requires a heatsink thermal resistance ≤ 3.5 °C/W under worst-case 6 W dissipation. PCB copper area (≥20 cm² 2 oz Cu) and forced airflow significantly improve thermal performance in confined engine bay spaces.
L9914A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- Multiwatt-8 (Straight Leads)
- Packaging:
- Tube
- Product Status:
- Last Time Buy
- Applications:
- Power Supply, Automotive Applications
- Voltage - Input:
- 8V ~ 16V
- Number of Outputs:
- 1
- Voltage - Output:
- -
- Operating Temperature:
- -35°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-Multiwatt
L9914A FAQ
1.How can I place an order for L9914A through Aetrix?
Please submit a Request for Quotation (RFQ) for L9914A on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for L9914A reliable?
The price and inventory of L9914A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L9914A is usually 5 days.
3.What payment methods are accepted for L9914A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L9914A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L9914A?
L9914A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L9914A order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for L9914A?
For technical support, including L9914A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L9914A requirements.
6.How does Aetrix verify that L9914A is sourced from the original manufacturer or authorized distributors?
All L9914A products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that L9914A meets industry standards.
7.What is the process for return or replacement of L9914A?
All L9914A units undergo pre-shipment inspection (PSI). If there is an issue with L9914A, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The L9914A part is unused and in its original packaging.
Return procedure for L9914A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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