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L9679P：Advanced airbag IC for low/mid end applications

The L9679P is an advanced airbag system chip solution targeted for mature airbag market and integrated safety markets. This device is family compatible with the L9678 and L9680 devices. Safety system integration is enabled through higher power supply currents and integrated PSI-5 satellite interface.

High frequency power supply design allows further cost reduction by using smaller and less expensive external components. All switching regulators operate at 1.882 MHz while buck converters have integrated synchronous rectifiers.

Additional attention is given to system integrity and diagnostics. The reserve capacitor is electrically isolated from the boost regulator by a 50 mA nominal fixed current source, controlling in-rush an additional capacitor discharge fixed current source is integrated to diagnose the reserve capacitor value and ESR. The same current sources can be used to discharge the capacitor at shutdown.

Thanks to low quiescent current, the device can be directly connected to battery. In this way, the device start-up and shutdown are controlled through the wake-up input function. The power supply and crossover function are controlled automatically through the internal state machine.

The user can select both ECU logic voltage (V_CCat 3.3 V or 5.0 V) and energy reserve output voltage (at either 23 V or 33 V). Deployment voltage is set to a maximum of 25 V for all profiles and can be controlled through external safing switch circuit using the high side safing switch reference enabled through the system SPI interface or the arming logic.

Key Features

• AEC-Q100 qualified
• Boost regulator for energy reserve
  • 1.882 MHz operation, Iload = 55 mA max
  • Output voltage user selectable, 23 V/ 33 V ±5%
  • Capacitor value & ESR diagnostics
• Boost regulator for PSI-5 SYNC pulse
  • 1.882 MHz operation,
  • Output voltage, 12 V/14.75 V, user configurable
• Buck regulator for remote sensor
  • 1.882 MHz operation
  • Output voltage, 7.2 V/9 V ±4%, user configurable
• Buck regulator for micro controller unit
  • 1.882 MHz operation
  • Output voltage user selectable, 3.3 V or 5.0 V ±3%
• Integrated energy reserve crossover switch
  • 3 Ω - 912 mA max
  • Switch active output indicator
• Battery voltage monitor & shutdown control with Wake-up control
• System voltage diagnostics with integrated ADC
• Squib deployment drivers
  • 8 channel HSD/LSD
  • 25 V max deployment voltage
  • Various deployment profiles
  • Current monitoring
  • Rmeasure , STB, STG & Leakage diagnostics
  • High & low side driver FET tests
• High side safing switch regulator and enable control
• Two channel remote sensor interface
  • PSI-5 satellite sensors
• Three channel GPO, HSD or LSD configurable, with PWM 0-100% control
• Nine channel hall-effect, resistive or switch sensor interface
• User customizable safing logic
• Specific disarm signal for passenger airbag
• Temporal and algorithmic Watchdog timers
• End of life disposal interface
• Temperature sensor
• 32 bit SPI communications
• 5.5 V minimum operating voltage at device battery pin
• Operating temperature, -40 to 95 °C
• Packaging - 100 pin

Product Specifications

Application Notes

Sample & Buy

Quality & Reliability