L9966 - Automotive System Basis Chip | STMicroelectronics
MPN: L9966 β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.5 | $4.50 |
| 10 | $4.05 | $40.50 |
| 100 | $3.6 | $360.00 |
| 500 | $3.24 | $1,620.00 |
| 1,000 | $2.88 | $2,880.00 |
Drop-in alternatives for L9966 β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
L9966T
β Drop-Inπ Reference alternative (not in catalog)
UJA1169
β Drop-Inπ Reference alternative (not in catalog)
TLE9471
β Drop-Inπ Reference alternative (not in catalog)
L9966 Maximum Ratings & Electrical Characteristics
| Input Voltage Range | 4.5 V to 28 V |
| LDO Output Voltage | 5 V |
| LDO Output Current | 500 mA |
| LDO Dropout Voltage | 300 mV at 500 mA |
| LDO Output Noise | 30 uVrms (10 Hz to 100 kHz) |
| Quiescent Current (Sleep) | 45 uA |
| LIN Transceiver | LIN 2.2A, SAE J2602 |
| High-Side Driver | 1 channel, 500 mA |
| SPI Interface | 16-bit, up to 5 MHz |
| Watchdog | Window watchdog |
| Operating Temperature | -40C to +125C |
| Package | VQFN-48 (7x7 mm) |
| Mounting Type | Surface Mount |
| AEC-Q100 | Qualified |
| RoHS | Compliant |
L9966 Pin Configuration
| Pin 1 | VCC β Power supply input |
| Pin 2 | GND β Ground |
| Pin 3 | LIN β LIN bus |
| Pin 4 | HSD β High-side driver output |
| Pin 5 | SPI_CS β SPI chip select |
| Pin 6 | SPI_CLK β SPI clock |
| Pin 7 | SPI_MOSI β SPI master out slave in |
| Pin 8 | SPI_MISO β SPI master in slave out |
| Pin 9 | LDO_OUT β LDO output |
| Pin 10 | WD β Watchdog input |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
L9966 is suitable for 6 applications: Body Control Module, Smart Junction Box, Lighting Control Unit, HVAC Control Module, Door Control Module, Seat Control Module.
Body Control Module
The L9966 provides the main 5V rail for the microcontroller, communicates via LIN, and drives loads such as interior lights and door locks. Its high-side driver simplifies load switching, and the SPI interface allows the MCU to read diagnostic status and configure the device. The wide input voltage range (4.5V to 28V) ensures operation during cranking and load dump. The integrated watchdog enhances system reliability by resetting the MCU if software hangs. Compared to discrete solutions, the L9966 reduces board space and component count, improving overall system cost and reliability.
Recommended
Smart Junction Box
In a smart junction box, the L9966 manages power distribution to various loads such as relays, LEDs, and sensors. Its high-side driver can directly switch loads up to 500mA, and the LIN interface allows communication with the central body controller. The SPI interface enables precise control and diagnostics. The L9966's low quiescent current (45uA) is critical for reducing battery drain when the vehicle is off. The device's thermal shutdown protection prevents damage during overload conditions. The compact VQFN-48 package allows for dense PCB layouts, saving space in the junction box.
Recommended
Lighting Control Unit
The L9966 can be used in lighting control units to drive LED modules and communicate with the vehicle network. The high-side driver can switch LED strings, and the LIN interface allows dimming commands from the body controller. The LDO provides a stable 5V rail for the microcontroller and LED driver ICs. The device's EMC performance ensures compliance with automotive standards. The window watchdog monitors the MCU, resetting it if necessary to prevent lighting failures. The L9966's thermal management features protect against overheating in high-temperature environments near headlights.
Recommended
HVAC Control Module
The L9966 is suitable for HVAC control modules, providing power and communication for blower motors, actuators, and sensors. The LDO powers the MCU, and the LIN interface connects to the central climate control unit. The high-side driver can control relays for compressor and fan. The SPI interface allows the MCU to read temperature and pressure sensor data. The device's wide input voltage range handles voltage fluctuations from the battery. The low quiescent current is beneficial for maintaining battery life when the vehicle is off. The L9966's robust protection features ensure reliable operation in the harsh automotive environment.
Recommended
Door Control Module
The L9966 can be used in door control modules to manage window lifts, door locks, and mirror adjustments. The high-side driver can control the window motor relay, and the LIN interface communicates with the central body controller. The LDO powers the MCU and sensors. The SPI interface allows the MCU to read switch states and diagnostic information. The device's low quiescent current is important for reducing battery drain when the door is not in use. The L9966's protection features prevent damage from short circuits and overcurrent conditions. The compact package fits well in the limited space inside a door module.
Recommended
Seat Control Module
The L9966 is used in seat control modules to manage seat motors, heaters, and memory functions. The high-side driver can control the seat motor relay, and the LIN interface communicates with the body controller. The LDO powers the MCU and sensors. The SPI interface allows the MCU to read seat position sensors and diagnostic information. The device's wide input voltage range ensures operation during cranking. The low quiescent current is beneficial for battery life. The L9966's protection features prevent damage from overloads. The compact package is ideal for space-constrained seat modules.
Recommended
Recommended Products Summary
Engineering reference data for L9966 β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | L9966T | L9965 | UJA1169 | TLE9471 |
|---|---|---|---|---|---|
| Package | VQFN-48 (7x7 mm) | VQFN-48 (7x7 mm) - same | VQFN-32 (5x5 mm) - different | VQFN-48 (7x7 mm) - same | VQFN-48 (7x7 mm) - same |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | NXP Semiconductors | Infineon |
| LDO Output Current | 500 mA | 500 mA | 300 mA | 500 mA | 500 mA |
| High-Side Driver | Yes (1 channel) | Yes (1 channel) | No | Yes (1 channel) | Yes (1 channel) |
| LIN Transceiver | LIN 2.2A, SAE J2602 | LIN 2.2A, SAE J2602 | LIN 2.2A, SAE J2602 | LIN 2.2A, SAE J2602 | LIN 2.2A, SAE J2602 |
| SPI Interface | 16-bit, up to 5 MHz | 16-bit, up to 5 MHz | 16-bit, up to 5 MHz | 16-bit, up to 5 MHz | 16-bit, up to 5 MHz |
| Quiescent Current (Sleep) | 45 uA | 45 uA | 40 uA | 50 uA | 55 uA |
| AEC-Q100 | Qualified | Qualified | Qualified | Qualified | Qualified |
Key Differentiators
- Integrated high-side driver (vs L9965)
- Higher LDO output current (vs L9965)
- Cross-brand compatibility (vs UJA1169)
Design Notes
The L9966 VQFN-48 package has an exposed pad that must be soldered to a large copper area on the PCB for effective heat dissipation. For typical applications with 500mA LDO load and 12V input, power dissipation is approximately 3.5W. Ensure the PCB copper area is at least 1 square inch to keep junction temperature below 125C.
Place a 100nF ceramic capacitor close to the VCC pin and a 10uF ceramic capacitor on the LDO output for stability. For the LIN bus, add a 1nF capacitor and a 220Ξ© series resistor for EMC protection. Keep SPI traces short and shielded to avoid noise coupling.
Do not exceed the maximum input voltage of 28V. Ensure the watchdog is properly configured to avoid false resets. The high-side driver output must be protected with a flyback diode when driving inductive loads. Verify SPI communication timing to avoid data corruption.
Compliance Information
AEC-Q100 qualified per STMicroelectronics product page. RoHS and REACH compliant.
