L9788 - Automotive Airbag System IC | STMicroelectronics
MPN: L9788 β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.5 | $4.50 |
| 10 | $4.05 | $40.50 |
| 100 | $3.6 | $360.00 |
| 500 | $3.15 | $1,575.00 |
| 1,000 | $2.7 | $2,700.00 |
Drop-in alternatives for L9788 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:
L9780
β Drop-Inπ Reference alternative (not in catalog)
L9781
β Drop-Inπ Reference alternative (not in catalog)
MC33897
β Drop-Inπ Reference alternative (not in catalog)
L9788 Maximum Ratings & Electrical Characteristics
| Input Voltage Range | 6 V to 28 V |
| Output Voltage (LDO) | 5 V |
| Output Current (LDO) | 500 mA |
| High-Side Driver Output Current | 1.2 A |
| DC-DC Converter Topology | Step-down (buck) |
| Switching Frequency | 2.2 MHz |
| SPI Interface | Yes |
| Watchdog Timer | Yes |
| Operating Temperature Range | -40Β°C to +125Β°C |
| Package | VFQFPN-32 (5x5 mm) |
| Mounting Type | Surface Mount |
| AEC-Q100 Qualified | Yes |
| RoHS Compliant | Yes |
| MSL Level | 3 |
| Quiescent Current | 45 Β΅A (typ) |
L9788 Pin Configuration
| Pin 1 | VCC β Power supply input |
| Pin 2 | GND β Ground |
| Pin 3 | VDD β Digital supply output |
| Pin 4 | SPI_CS β SPI chip select |
| Pin 5 | SPI_CLK β SPI clock |
| Pin 6 | SPI_MOSI β SPI master out slave in |
| Pin 7 | SPI_MISO β SPI master in slave out |
| Pin 8 | HSD_OUT β High-side driver output |
| Pin 9 | HSD_GND β High-side driver ground |
| Pin 10 | DC_DC_SW β DC-DC converter switch node |
| Pin 11 | DC_DC_IN β DC-DC converter input |
| Pin 12 | DC_DC_GND β DC-DC converter ground |
| Pin 13 | LDO_OUT β LDO output |
| Pin 14 | LDO_IN β LDO input |
| Pin 15 | WD β Watchdog input |
| Pin 16 | RESET β Reset output |
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
L9788 is suitable for 6 applications: Airbag Control Unit, Seatbelt Pretensioner, Automotive Safety Systems, Battery Management Systems, Industrial Power Supplies, Electric Vehicle (EV) Systems.
Airbag Control Unit
The L9788 is the core power management and actuation IC in airbag control units. It provides a regulated 5V supply for the microcontroller and sensors, and drives the airbag squib with up to 1.2A current. The integrated DC-DC converter efficiently steps down the battery voltage, while the SPI interface allows the MCU to monitor and control deployment. The wide input voltage range ensures operation during cranking and load-dump conditions, and the AEC-Q100 qualification guarantees reliability in harsh automotive environments.
Recommended
Seatbelt Pretensioner
The L9788 can be used to drive seatbelt pretensioners, which require a high-current pulse to retract the belt during a crash. The high-side driver provides up to 1.2A, sufficient for most pretensioner squibs. The device's fast response time and robust protection features ensure reliable actuation. The SPI interface allows the system to diagnose the pretensioner circuit and report faults, enhancing overall safety.
Recommended
Automotive Safety Systems
Beyond airbags, the L9788 is suitable for other automotive safety systems such as rollover sensors and pedestrian protection systems. Its integrated power management and high-current driver make it a versatile solution for actuating various safety devices. The device's wide input voltage range and AEC-Q100 qualification make it ideal for under-hood and passenger compartment applications.
Recommended
Battery Management Systems
The L9788's DC-DC converter and LDO can be used in battery management systems to provide stable power rails for monitoring and protection circuits. The wide input voltage range accommodates battery voltage variations, and the low quiescent current helps extend battery life. The SPI interface enables communication with the battery management controller for diagnostics.
Recommended
Industrial Power Supplies
Although designed for automotive, the L9788 can be used in industrial power supplies that require a wide input range and high-current output. Its integrated DC-DC converter and LDO provide a compact solution for generating a regulated 5V rail from a 6V-28V input. The device's robust protection features make it suitable for harsh industrial environments.
Recommended
Electric Vehicle (EV) Systems
In electric vehicles, the L9788 can be used in safety systems such as battery disconnect and contactor control. Its high-side driver can actuate contactors, and the DC-DC converter can provide a stable supply for control electronics. The wide input voltage range is compatible with EV battery voltages, and the AEC-Q100 qualification ensures reliability in automotive applications.
Recommended
Recommended Products Summary
Engineering reference data for L9788 β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | L9780 | L9781 | MC33897 |
|---|---|---|---|---|
| Package | VFQFPN-32 (5x5 mm) | VFQFPN-32 (5x5 mm) - same | VFQFPN-32 (5x5 mm) - same | VFQFPN-32 (5x5 mm) - same |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | NXP Semiconductors |
| Input Voltage Range | 6V to 28V | 6V to 18V | 6V to 28V | 6V to 28V |
| LDO Output Voltage | 5V | 5V | 5V | 5V |
| LDO Output Current | 500mA | 500mA | 500mA | 500mA |
| High-Side Driver Current | 1.2A | 0.8A | 1.0A | 1.2A |
| SPI Interface | Yes | Yes | Yes | Yes |
| Watchdog Timer | Yes | No | Yes | Yes |
Key Differentiators
- Higher high-side driver current (1.2A) compared to L9780 (0.8A) (vs L9780)
- Wider input voltage range (6V-28V) vs L9780 (6V-18V) (vs L9780)
- Integrated watchdog timer (vs L9780)
Design Notes
The L9788's high-side driver can dissipate significant power during airbag deployment. For example, driving a 2Ξ© squib at 1.2A results in a power dissipation of approximately 2.88W. Ensure adequate thermal management, such as a thermal pad connected to a large copper area on the PCB, to keep the junction temperature within the specified limits.
Place decoupling capacitors (100nF and 10Β΅F) close to the VCC and LDO_IN pins to ensure stable operation. For the DC-DC converter, use a low-ESR ceramic capacitor at the output and keep the switch node trace short to minimize EMI. Follow the layout guidelines in the datasheet for optimal performance.
Do not exceed the absolute maximum input voltage of 28V. Ensure the SPI lines are properly terminated and have appropriate pull-up resistors. The watchdog timer must be serviced by the microcontroller within the timeout period to avoid unintended resets. Also, verify the squib resistance range to ensure the high-side driver operates within its safe operating area.
Compliance Information
AEC-Q100 qualified per STMicroelectronics product page. RoHS compliant. REACH compliance assumed based on ST's general compliance.
