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Low end System Basis Chip for Airbag including PSI5 remote sensor interface

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Product overview


The L9678P IC is a system chip solution targeted for emerging market applications. Base system designs can be completed with the L9678P, SPC560Px microcontroller and an on-board acceleration sensor or PSI5 sensor.

Energy reserve voltage is derived through a cost effective high frequency boost regulator. High frequency operation allows the user to pick up low value and cheap inductance. The voltage is programmable to 23 V or 33 V nominal.

Battery voltage is sensed through the VBATMON pin providing start-up and shutdown control for the system. Once battery voltage drops below the minimum operating voltage, the device enables the integrated crossover switch to permit orderly shutdown.

L9678P offers two linear regulators (5 V with external pass transistor and fully integrated 3.3 V). User can use one of these regulators to supply µC. Input/output pins are compatible with both ranges by dedicated supply pin VDDQ. External pass transistor gives the flexibility to easily address different current loads in case of different micro-controllers.

One optional 7.2 V linear regulator with external pass transistor can be used to supply remote sensor interface.

External acceleration data is received through the PSI-5 remote sensor interface. Both channels have independent decoders. Sensor data and diagnostics are available via SPI.

The safing logic monitors inertial sensors (remote sensors via PSI-5 or on-board sensors via SPI) to determine if a crash event is in progress, thereby enabling deployment to occur. Parameters for sensor configuration and thresholds are user programmable.

Squib/pyroswitch/pyroswitch deployment uses four independent high and low side drivers, capable of deploying at 25 V max. Diagnostic data control is provided through the SPI interface.

The Hall-effect, resistive or switch sensor interface can be used to determine the state of external switch devices, such as buckle switches, seat track position sensors, weight sensors, deactivation switches.

The integrated clock module provides a fixed clock signal for the microcontroller. The clock module provides the user the option of deleting the commonly used resonator or crystal.

  • All features

    • AEC-Q100 qualified
    • Energy reserve voltage power supply
      • High frequency boost regulator, 1.882 MHz
      • Output voltage user selectable, 23 V or 33 V ±5%
    • User configurable linear power supplies
      • 5.0 V and 7.2 V ±4% output voltages
      • External pass transistor
    • Fully integrated 3.3 V ±4% linear regulator
    • Battery voltage monitor and shutdown control with wake-up control
    • System voltage diagnostics with integrated ADC
    • Crossover switch
      • Crossover performance, max 3 Ω, 600 mA max.
    • Squib/pyroswitch deployment drivers
      • 4 channel HSD/LSD
      • 25 V maximum deployment voltage
      • 1.2 A @ 2 ms and 1.75 A @ 0.5/0.7 ms deployment profiles
      • Integrated safing FET linear regulator, 20 V/25 V nominal
      • Current monitoring
      • Rmeasure, STB, STG and leakage diagnostics
      • High and low side driver FET tests
      • Safing FET test
    • User customizable safing logic
    • Two channel PSI-5 remote sensor interface (asynchronous mode), [only for L9678P-S version]
    • Four channel hall-effect, resistive or switch sensor interface
    • ISO9141 transceiver
    • Dual channel configurable high-side/low-side LED driver
    • Watchdog timer
    • Two integrated oscillators: 7.5/16 MHz
    • Temperature sensor
    • 32 bit SPI communications
    • Minimum operating voltage = 6 V
    • Operating temperature, -40 °C to 95 °C
    • Packaging - 64 pin

EDA Symbols, Footprints and 3D Models

STMicroelectronics - L9678P-S

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Quality and Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
LQFP 64 10x10x1.4 mm Automotive Ecopack2



LQFP 64 10x10x1.4 mm

Material Declaration**:


Marketing Status



LQFP 64 10x10x1.4 mm



RoHS Compliance Grade


(**) The Material Declaration forms available on st.com may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.

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