L9788 - Automotive Airbag System IC | STMicroelectronics
MPN： L9788 ✓ 啟用中L9788 概覽
An airbag system IC is a specialized power management and actuation device used in automotive safety systems. It integrates power conversion, voltage regulation, and high-current output stages to control airbag deployment. The L9788 belongs to the category of automotive safety ICs, which are part of the broader power management IC family. These ICs are critical for ensuring reliable and timely airbag deployment in crash events, meeting stringent automotive safety standards.
Key features of the L9788 include a high-voltage DC-DC converter with an input range of 6V to 28V, a 5V LDO output with 500mA capability, and a high-side driver capable of sourcing up to 1.2A for airbag squib firing. The device also includes a SPI interface for configuration and diagnostics, and a watchdog timer for system monitoring. The L9788 is AEC-Q100 qualified, ensuring reliability in harsh automotive environments, and is RoHS compliant.
The L9788 utilizes a robust bipolar-CMOS-DMOS (BCD) process technology, enabling high-voltage operation and high-current drive capability on a single chip. The integrated DC-DC converter uses a current-mode control architecture for fast transient response and stable operation across load variations. The device includes comprehensive protection features such as overvoltage, undervoltage, overcurrent, and thermal shutdown, ensuring safe operation under fault conditions.
Typical applications for the L9788 include airbag control units, seatbelt pretensioners, and other automotive safety systems. Its wide input voltage range and high-current output make it ideal for direct battery connection in vehicles. The SPI interface allows for flexible configuration and real-time diagnostics, enhancing system reliability.
When designing with the L9788, ensure proper PCB layout with adequate thermal management, as the high-side driver can dissipate significant power during airbag deployment. Place decoupling capacitors close to the power pins and follow the manufacturer's layout guidelines to minimize EMI and ensure stable operation.
直接替換替代品，適用於 L9788 — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： L9788 （相同外形與佔位） — 差異在於 Package, AEC-Q100 Qualified.
L9780
✅ 直接替換 ⚠️ 規格未經驗證聯絡詢價
查看資料表 →L9781
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
MC33897
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
L9788 最大額定值與電氣特性
| 輸入電壓範圍 | 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) |
| 切換頻率 | 2.2 MHz |
| SPI Interface | Yes |
| Watchdog Timer | Yes |
| 工作溫度範圍 | -40°C to +125°C |
| 封裝 | VFQFPN-32 (5x5 mm) |
| 安裝類型 | Surface Mount |
| AEC-Q100 Qualified | Yes |
| RoHS Compliant | Yes |
| MSL 等級 | 3 |
| 靜態電流 | 45 µA (typ) |
L9788 腳位配置
| 腳位 1 | VCC — Power supply input |
| 腳位 2 | GND — Ground |
| 腳位 3 | VDD — Digital supply output |
| 腳位 4 | SPI_CS — SPI chip select |
| 腳位 5 | SPI_CLK — SPI clock |
| 腳位 6 | SPI_MOSI — SPI master out slave in |
| 腳位 7 | SPI_MISO — SPI master in slave out |
| 腳位 8 | HSD_OUT — High-side driver output |
| 腳位 9 | HSD_GND — High-side driver ground |
| 腳位 10 | DC_DC_SW — DC-DC converter switch node |
| 腳位 11 | DC_DC_IN — DC-DC converter input |
| 腳位 12 | DC_DC_GND — DC-DC converter ground |
| 腳位 13 | LDO_OUT — LDO output |
| 腳位 14 | LDO_IN — LDO input |
| 腳位 15 | WD — Watchdog input |
| 腳位 16 | RESET — Reset output |
典型應用
L9788 適用於 6 應用s: 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.
推薦
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.
推薦
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.
推薦
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.
推薦
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.
推薦
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.
推薦
推薦產品摘要
工程參考資料，適用於 L9788 — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | 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 |
主要差異化特點
- Higher high-side driver current (1.2A) compared to L9780 (0.8A) (對比L9780)
- Wider input voltage range (6V-28V) vs L9780 (6V-18V) (對比L9780)
- Integrated watchdog timer (對比L9780)
設計說明
The L9788's high-side driver can dissipate significant power during airbag deployment. For example, driving a 2Ω 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 10µF) 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.
合規資訊
AEC-Q100 qualified per STMicroelectronics product page. RoHS compliant. REACH compliance assumed based on ST's general compliance.
