Analog, Mixed-Signal and Power Management MC33789 Airbag system basis chip (SBC) with power supply and PSI5 sensor interface Applications MC33789 Simplified Application Drawing • Automotive Airbag Safety Systems Basic Airbag Systems Advanced Airbag Systems MC33789 VBAT • Motorcycle – ATV Safety Systems Frame Mounted Single Loop Airbag System The MC33789 is a mixed signal IC for airbag safety applications. The MC33789 provides a cost effective and flexible system IC solution across the range of airbag partitions used in cars and other vehicles. The MC33789 connects to the 12 V vehicle battery and supplies the multiple voltages of a typical airbag system. The MC33789 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 MC33789 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 well suited for use in low to high end airbag safety systems by allowing the designer to scale a design for the number of firing loops needed while providing enhanced safety and system reliability. IN1 IN2 9 Input Monitors IN8 IN9 LIN PSI5_1 4 Satellite Sensor Interfaces Wake Up WAKE BSTSW 33 V VBST VER PSI5_2 PSI5_3 VBAT VPWR ERSW PSI5_4 VPWR OUT1_D OUT1_S 5.0 V X/Y Axis Accel. Sensor Sensor SPI 5.0 V VFIRE_x SQB_H1 SQB_H1 BUCKSW VBUCK VCCDRI SPI 5.0 V Energy Storage 9.0 V 5.0 V Output Squib Driver 1 VCC SQB_L1 5.0 V SPI_A VDD AIN SQB_L1 AOUT ARM RESET RESET SPI_B MCU Squib Driver 2 FEN_1 FEN_2 Squib Driver SPI 2 ARM_X and ARM_Y for Squib Driver 2 FENs RESET SPI Cross-coupled Squib Connections MC33789 Key Features • Designed to operate 5.2 V ≤ VPWR ≤ 20 V, up to 40 V transients Performance Performance Typical Values Operating Voltage 5.2 V ≤ VPWR ≤ 20 V • Safing state machine with programmable sensing thresholds Energy Reserve and Squib Firing Supply 33 V VCC Supply 5.0 V • Two configurable high side/low side drivers with PWM capability Selectable Switch Input Detector Supplies 1.5 V, 2.5 V, 5.0 V, 6.5 V Configurable Driver Output Voltage Output Current PWM Frequency 0 V / VPWR Min 70 mA 128 Hz Analog Output Voltage 0 V ≤ VAOUT ≤ VCC ESD (HBM) ±2000 V Ambient Operating Temperature (TA) -40 °C to+125 °C Junction Temperature (TJ) -40 °C to+150 °C • 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 supplies for squib firing (33 V), satellite sensors (6.3 V), and local ECU sensors and logic circuits (5.0 V) • Nine configurable switch input monitors for simple switch and Hall-effect sensor interfaces with internal power supply • 16-bit SPI interface Protection Protection Detect Over-voltage • Over-current/SC • Over-temperature • Open load • Limiting • Shut Down Auto Retry Status Reporting • • • • • • • • Ordering Information • LIN 2.1 physical layer interface Part Number Temperature Range Package Questions MCZ33789AE/R2 -40 °C to 125 °C 64 LQFP-EP Contact Sales Evaluation board to demonstrate the key features of the MC33789 MC33789 Airbag System Basis Chip (SBC) with Power Supply and PSI5 Sensor Interface - Data Sheet SG1002 Analog and Power Management device comparison - Selector Guide SG187 Automotive Selector Guide • Question – Why are there no squib drivers integrated? Answer – The number of squib drivers varies across vehicle platforms so a fixed number could be too many or not enough for an application. • Question – What drove the MC33789 final silicon partition? Answer – The MC33789 was the result of collaboration between Freescale and a leading airbag system supplier who addressed the need for low cost vs. flexibility • Question – Is the MC33789’s PSI5 Interface interoperable with other PSI5 products? • Benefits • Master interface supports the PSI5 standard, V1.3. . • Provides an integrated solution for almost all auxiliary functions in a typical airbag control module AE SUFFIX (PB-FREE) EXPOSED PAD 98ASA10763D 64-PIN LQFP • Automotive temperature range and qualification • Suitable for uses from low squib count to high squib count airbag systems Answer – Yes, Freescale is part of the PSI5 consortium and has an ecosystem of crash sensor parts that communicate with the MC33789. The MC33789’s PSI5 master interface supports the P10P 500/3L operation mode specified in the PSI5 standard V1.3. Learn More: For current information about Freescale products, please visit www.freescale.com. Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc., 2010 - 2011 All rights reserved. Document Number: MC33789FS, Rev. 2.0