Overview
The L9679P is an advanced system chip solution developed by STMicroelectronics, primarily targeted for the cut-off battery market and advanced airbag systems. This device is part of a family that includes the L9678 and L9680, ensuring compatibility and ease of integration across various safety systems. It is designed to enhance safety system integration through higher power supply currents and integrated PSI-5 satellite interfaces. The L9679P features a high-frequency power supply design, allowing for cost reduction by using smaller and less expensive external components. It also includes comprehensive system integrity and diagnostics, making it a robust solution for automotive safety applications.
Key Specifications
| Parameter | Description |
|---|---|
| Operating Voltage | 5.5 V minimum at device battery pin |
| Operating Temperature | -40 to 95 °C |
| Package | TQFP 100 14x14x1.0 |
| Grade | Automotive |
| RoHS Compliance | Ecopack2 |
| Boost Regulator Frequency | 1.882 MHz |
| Energy Reserve Output Voltage | User selectable, 23 V or 33 V ± 5% |
| PSI-5 SYNC Pulse Output Voltage | User selectable, 12 V or 14.75 V ± 5% |
| Remote Sensor Output Voltage | User selectable, 7.2 V or 9 V ± 4% |
| Logic Voltage (VCC) | User selectable, 3.3 V or 5.0 V ± 4% |
| Deployment Voltage | Maximum of 25 V |
| Deployment Profiles | Various profiles, up to 4.032 ms deployment time |
| SPI Communication | 32-bit SPI |
Key Features
- AEC-Q100 qualified
- Boost regulator for energy reserve with user-selectable output voltage (23 V or 33 V ± 5%)
- Boost regulator for PSI-5 SYNC pulse with user-selectable output voltage (12 V or 14.75 V ± 5%)
- Buck regulator for remote sensors with user-selectable output voltage (7.2 V or 9 V ± 4%)
- Buck regulator for microcontroller unit with user-selectable output voltage (3.3 V or 5.0 V ± 4%)
- Integrated energy reserve crossover switch with 3 Ω - 912 mA max performance
- Battery voltage monitor and shutdown control with wake-up control
- System voltage diagnostics with integrated ADC
- Squib/pyroswitch deployment drivers with 8 channel HSD/LSD and various deployment profiles
- Current monitoring and diagnostics for Rmeasure, STB, STG, and leakage
- High and low side driver FET tests and safing FET test
- Two-channel interface for PSI-5 remote sensors and two channels for active wheel speed sensors
- Three-channel GPO, HSD or LSD configurable, with PWM 0-100% control
- Nine-channel interface for Hall-effect, resistive or switch sensors
- User customizable safing logic and specific disarm signal for passenger airbag
- Temporal and algorithmic Watchdog timers and end of life disposal interface
- Temperature sensor and 32-bit SPI communication
Applications
The L9679P is designed for use in advanced airbag systems and cut-off battery systems, particularly in the automotive sector. It is suitable for both mature airbag markets and integrated safety markets. The device's features make it an ideal solution for safety-critical applications where reliable power management, diagnostics, and deployment control are essential.
Q & A
- What is the primary application of the L9679P?
The L9679P is primarily used in advanced airbag systems and cut-off battery systems for integrated safety markets.
- What are the key power supply regulators in the L9679P?
The device includes boost regulators for energy reserve and PSI-5 SYNC pulse, and buck regulators for remote sensors and microcontroller units.
- What is the operating frequency of the boost regulators?
The boost regulators operate at 1.882 MHz.
- What is the maximum deployment voltage for the squib/pyroswitch deployment drivers?
The maximum deployment voltage is 25 V.
- How many channels are available for PSI-5 remote sensors and active wheel speed sensors?
There are two channels for each type of sensor.
- What is the purpose of the integrated energy reserve crossover switch?
The integrated energy reserve crossover switch provides a crossover performance of 3 Ω - 912 mA max and includes a switch active output indicator.
- What diagnostics are available for the system voltage and reserve capacitor?
The device includes system voltage diagnostics with an integrated ADC and diagnostics for the reserve capacitor value and ESR.
- Can the safing logic be customized by the user?
- What communication interface is used by the L9679P?
The device uses a 32-bit SPI communication interface.
- What is the operating temperature range of the L9679P?
The operating temperature range is -40 to 95 °C.
