MC33789 Airbag System Basis Chip (SBC) with Power Supply and PSI5 Sensor Interface

MC33789_IMG   The 33789 is a mixed signal IC for airbag safety applications. The 33789 provides a cost effective and flexible system IC solution across the range of airbag partitions used in cars and other vehicles. The 33789 connects to the 12 V vehicle battery and supplies the multiple voltages of a typical airbag system. The 33789 can detect switched input states, communicate with both local and remote crash sensors. It offers an industry standard interface (SPI) and four PSI5 master interfaces. The 33789 has a dedicated safing state machine that complements the airbag’s MCU hardware/ software safing approach. Also included are a diagnostic – self protection capability and a programmable analog interface accessible by the system MCU.

The MC33789 is a SafeAssure functional safety solution.


  • Designed to operate 5.2 V ≤ VPWR ≤ 20 V, up to 40 V transients
  • Safing state machine with programmable sensing thresholds
  • Two configurable high side/low side drivers with PWM capability
  • Four PSI5 satellite sensor master interfaces
  • Self-protected and diagnostic capability
  • System power mode control with watchdog and system Power On Reset (POR)
  • Supports complete airbag system power supply architecture, including system power mode control, supplies for squib firing (33 V), satellite sensors (6.3 V), and local ECU sensors and ECU logic circuits (5.0 V)
  • Nine configurable switch input monitors for simple switch and Hall-effect sensor interfaces
  • 16-bit SPI interface
  • LIN 2.1 physical layer interface

Block Diagram


Related Products

  • MC33797:Four Channel Squib Driver IC
  • MMA1250KEG:±5g, Z-Axis, Analog Accelerometer
  • MMA51xxW:±60g, ±480g, Z-Axis, Analog PSI5 Airbag Sensor
  • MMA52xx:±60g, ±480g, X-Axis, Analog PSI5 Airbag Sensor
  • MMA68xxKW:±20g, 120g, 2-Axis (XY), SPI Airbag Sensor

Target Applications

  • Automotive
    • PSI5 Airbag System

Featured Documentation

  • MC33789: MC33789, Airbag System Basis Chip (SBC) with Power Supply and PSI5 Sensor Interface
  • MC33789FS: MC33789FS, Airbag System Basis Chip (SBC) with Power Supply and PSI5 Sensor Interface
  • AIRBAGFS: Automotive Airbag Safety Systems – Fact Sheet
  • AN4388: AN4388, Quad Flat Package (QFP) – Application Note



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