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STMicroelectronics L9918
- Part No.:
- L9918
- Manufacturer:
- STMicroelectronics
- Category:
- Special Purpose Regulators
- Package:
- Pentawatt-5 (Straight Leads, Staggered Depth)
- Datasheet:
-
L9918.pdf
- Description:
- ALTERNATOR VOLTAGE REGULATOR WIT
- Quantity:
- Payment:
- Shipping:
Inventory:989
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Product details
Overview
L9918 from STMicroelectronics is an automotive-grade alternator voltage regulator IC with integrated LIN 2.2A interface, high-side excitation driver, and NVM-programmable parameters for 12 V systems. It regulates battery voltage via closed-loop rotor current control, features thermal shutdown (170–190 °C), load response control (LRC), and supports 5–9 pole-pair alternators in engine bay environments.
For engineers reviewing the L9918 datasheet, L9918 pinout, L9918 application, or L9918 equivalent, key selection criteria include LIN protocol compliance (v1.3/2.1/2.2/2.2A), phase-sense self-start activation, internal freewheeling circuit, thermal protection thresholds, and ASIL-B readiness per ISO 26262.
Technical Context
The L9918 implements a digital LIN-based control loop where setpoint voltage is dynamically commanded by the ECU and enforced via PWM-modulated high-side EXC output driving the alternator rotor. Phase (PH) input enables speed sensing, stator monitoring, and self-start detection without external components.
Its regulation architecture integrates thermal compensation, slew-rate control (disabled above 125–145 °C), and dual-stage thermal shutdown (Tsd,1–Tsd,4) with hysteresis. The device embeds a dedicated LIN transceiver compliant with VDA LIN-Generator-Regulator specification and meets AEC-Q100 Grade 0 (−40 °C to +150 °C ambient).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| LIN Compliance | PHY layer compliant with LIN 2.2A; DLL layer compliant with LIN 1.3, 2.1, 2.2, and 2.2A - ensures interoperability with automotive ECUs. |
| Excitation Output | High-side MOSFET driver (EXC pin) with integrated freewheeling circuit - eliminates need for external flyback diode. |
| Thermal Shutdown | Configurable thresholds: Tsd,1 = 170–190 °C; hysteresis = 2–10 °C - prevents latch-up during sustained overload. |
| Supply Range | B+ operating range: 6–18 V; transient tolerance: 58–64 V clamp (load dump) - survives automotive battery transients. |
| Phase Sense Input | PH pin monitors stator winding for rotor speed, voltage level, and self-start detection - enables zero-RPM activation. |
| NVM Programmability | 13 configurable LIN frames + NVM parameter table A1 - supports calibration and alternator variant mapping without hardware change. |
Pinout & Package
L9918 is available in PENTAWATT In Line (TO-220-5) package with exposed thermal pad; junction-to-case thermal resistance is 2 °C/W. Bare die version (L9918BDTR) is also offered for embedded brush holder integration.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EXC (Pin 1) | High-side excitation driver output | Drives alternator rotor coil; includes internal freewheeling path - no external diode required. |
| B+ (Pin 2) | Power supply and battery voltage sense | Supplies IC and feeds regulation loop feedback - enables direct battery voltage monitoring without divider. |
| GND (Pin 3) | Regulator ground reference | Single ground terminal for all analog/digital functions - simplifies PCB layout and noise isolation. |
| LIN (Pin 4) | LIN bus transceiver I/O | Single-wire bidirectional communication interface - compliant with LIN spec v1.3–2.2A and VDA generator-regulator profile. |
| PH (Pin 5) | Stator phase sense input | Detects rotor position/speed and enables self-start at standstill - eliminates need for Hall sensor or crank signal. |
Key Features
| Feature | Design Value |
|---|---|
| Closed-loop voltage regulation | Maintains stable 12 V system voltage under dynamic load/speed changes using ECU-commanded setpoint and internal reference. |
| Load Response Control (LRC) | Adaptive current slew rate and return-LRC minimize voltage overshoot during sudden load transitions - improves EMI performance. |
| ASIL-B functional safety readiness | Fully compliant with ISO 26262 requirements for safety mechanisms, diagnostics, and fault reporting - reduces ASIL-B system integration effort. |
| VDA LIN-Generator-Regulator compliance | Meets German automotive OEM specification for generator control - enables direct qualification in VW, BMW, Daimler platforms. |
| Thermal compensation | Adjusts regulation setpoint vs. junction temperature - maintains battery charging accuracy across full operating range (−40 °C to +150 °C). |
Applications
| Engine Start-Stop Systems | 12 V Mild Hybrid Powertrain |
|---|---|
Use Scenario: Vehicle stops at traffic light and restarts engine within <500 ms using belt-driven starter-generator. IC Role / Device Role / Timing Role: Alternator regulator controls rotor excitation to deliver precise torque and maintain 12 V bus stability during cranking and regen phases. Use Value: Enables seamless start-stop operation with <±0.3 V bus deviation and supports >300,000 cycles per lifetime. |
Use Scenario: Regenerative braking energy captured and stored in 12 V battery via integrated starter-generator. IC Role / Device Role / Timing Role: LIN-controlled regulator modulates field current in real time to match ECU power demand and battery state-of-charge. Use Value: Achieves >92% charge efficiency across 6–18 V input range and supports dynamic setpoint updates at 10 Hz. |
| Electric Power Steering (EPS) | Advanced Driver Assistance Systems (ADAS) |
Use Scenario: EPS motor draws peak current (>80 A) during parking maneuvers, causing transient voltage sag on 12 V bus. IC Role / Device Role / Timing Role: L9918's fast LRC and PH-based phase tracking suppresses voltage dip by preemptively increasing rotor current before load step. Use Value: Limits bus sag to <0.8 V during 50 ms load steps - prevents EPS controller reset and maintains steering assist. |
Use Scenario: ADAS camera, radar, and domain controller require clean, stable 12 V supply with <10 mV ripple under all operating conditions. IC Role / Device Role / Timing Role: Regulator provides low-noise, thermally compensated voltage reference and LIN-based health reporting to ADAS ECU. Use Value: Delivers <5 mV RMS ripple at 12 V output and reports thermal/fault status every 100 ms via LIN diagnostic frame. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar alternator regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Infineon TLE8888 | Integrated dual high-side drivers; no PH input; uses CAN instead of LIN; requires external NVM for configuration. | Targeted at heavy-duty diesel alternators with dual-field windings; lacks phase-sense self-start capability. | Select when CAN bus infrastructure exists and dual-excitation control is required; not suitable for compact 12 V gasoline platforms. |
| NXP MC33816 | Single high-side driver; LIN 2.0 only; no thermal shutdown hysteresis tuning; fixed 7-pole-pair support. | Designed for cost-sensitive entry-level vehicles; limited NVM parameter sets (6 frames vs. 13); no VDA compliance. | Choose for legacy LIN 2.0 systems where VDA certification and multi-pole flexibility are not required. |
Compared with TLE8888 and MC33816, L9918 uniquely combines PH-based self-start, VDA-compliant LIN 2.2A, configurable pole-pair support (5–9), and tunable thermal thresholds - making it optimal for modern start-stop and mild hybrid 12 V architectures.
Availability
L9918 is available at Aetrix Electronics and suitable for engine control units, 12 V mild hybrid powertrains, and electric power steering systems requiring stable component supply with automotive-grade reliability and long lifecycle support.
Supply support for L9918 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, sensors, and automotive ASICs for industrial and automotive markets.
L9918 belongs to ST's Automotive Power & Analog Drivers product line, engineered specifically for intelligent alternator control in ASIL-B-compliant 12 V vehicle electrical systems with LIN-based ECU coordination.
FAQ
What is the maximum transient voltage the L9918 B+ pin can withstand?
The L9918 B+ pin features an internal clamp structure rated at 58–64 V for transient load-dump events lasting less than 400 ms. This meets ISO 7637-2 Pulse 5a requirements for 12 V automotive systems and protects against battery disconnection spikes without external TVS diodes.
Does L9918 require external components for LIN bus termination?
No external termination resistor is needed: the L9918 integrates a LIN bus pull-up to VBAT and a controlled slew-rate driver compliant with LIN 2.2A physical layer specifications. Only a 220 pF capacitor (C2) between LIN and GND is recommended for RF filtering per DB3952 layout guidance.
How does the PH pin enable self-start functionality?
The PH pin detects AC voltage amplitude and zero-crossings from a stator winding. At standstill, residual magnetism induces small PH signals; the IC uses this to detect rotor position and initiate excitation. Once rotation begins, PH provides real-time speed feedback for closed-loop regulation - eliminating need for crankshaft position sensor input.
Can L9918 be used with alternators having fewer than 5 pole pairs?
No - L9918 is factory-configured for 5, 6, 7, 8, or 9 pole-pair alternators only. Its PH input conditioning, regulation timing, and LRC algorithms are optimized for this range. Using it with 2–4 pole alternators would cause incorrect speed estimation and unstable voltage regulation due to mismatched electrical cycle-to-mechanical RPM mapping.
L9918 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- Pentawatt-5 (Straight Leads, Staggered Depth)
- Packaging:
- Tube
- Product Status:
- Active
- Applications:
- Alternator
- Voltage - Input:
- -
- Number of Outputs:
- 1
- Voltage - Output:
- 12V
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 5-PENTAWATT
L9918 FAQ
1.How can I place an order for L9918 through Aetrix?
Please submit a Request for Quotation (RFQ) for L9918 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 L9918 reliable?
The price and inventory of L9918 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L9918 is usually 5 days.
3.What payment methods are accepted for L9918?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L9918 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L9918?
L9918 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L9918 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 L9918?
For technical support, including L9918 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L9918 requirements.
6.How does Aetrix verify that L9918 is sourced from the original manufacturer or authorized distributors?
All L9918 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 L9918 meets industry standards.
7.What is the process for return or replacement of L9918?
All L9918 units undergo pre-shipment inspection (PSI). If there is an issue with L9918, 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 L9918 part is unused and in its original packaging.
Return procedure for L9918:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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