EyebrowMixed Signal and Power Management Analog, Headline MC33789 Target Applications • Automotive Airbag Safety Systems Airbag system basis chip (SBC) with power supply and PSI5 sensor interface Overview Basic Airbag Systems The MC33789 is a mixed signal IC for airbag safety applications. The MC33789 is a Advanced Airbag Systems SafeAssure functional safety solution. The MC33789 provides a cost effective and flexible • Motorcycle - ATV Safety Systems system IC solution across the range of airbag partitions used in cars and other vehicles. Frame Mounted Single Loop The MC33789 connects to the 12 V vehicle battery and supplies the multiple voltages of a Airbag System 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. MC33789 Simplified Application Drawing MC33789 VBAT 9 Input Monitors Wake Up IN1 WAKE IN2 VPWR IN8 BSTSW VBAT IN9 33V VBST PSI5_1 PSI5_2 VER 4 Satellite Sensor Interfaces PSI5_3 5V Energy Reserve PSI5_4 ERSW 5V VFIRE_x SQB_H1 VBAT OUT1_D OUT1_S 5V 5V BUCKSW VBUCK VCCDRI X/Y-axis Accel. Sensor Sensor SPI SPI AOUT RESET SPI_A SQB_H1 9V 5V Output Squib Driver 1 Squib Driver 2 VCC SQB_L1 LIN ARM FEN_1 SQB_L1 FEN_2 AIN RESET Squib Driver SPI SPI_B MCU RESET SPI 2 ARM_X and ARM_Y for Squib Driver 2 FENs Cross-coupled Squib Connection SafeAssure Protection, Performance, and Ordering Information The MC33789, a SafeAssure solution, is well suited for use in low to high end airbag Performance safety systems by allowing the designer Performance Typical Values to scale a design for the number of firinig Operating Voltage 5.2 V < VPWR < 20 V safety and system reliability. Energy Reserve and Squib Firing Supply 33 V SafeAssure Program: Functional Safety, Simplified VCC Supply 5.0 V Selectable Switch Input Detector Supplies 1.5 V, 2.5 V, 5.0 V, 6.5 V loops needed while providing enhanced Freescale’s SafeAssure functional safety Configurable Driver Output Voltage Output Current PWM Frequency 0 V / VPWR Min 70 mA 128 Hz Analog Output Voltage 0 V < VAOUT < VCC Commission (IEC) 61508. The program ESD (HBM) ±2000 V highlights Freescale solutions – hardware Ambient Operating Temperature (TA) -40 °C to +125 °C and software – that are optimally designed Junction Temperature (TJ) -40 °C to +150 °C program is designed to help system manufacturers more easily achieve system compliance with functional safety standards: International Standards Organization (ISO) 26262 and International Electrotechnical to support functional safety implementations Protection and come with a rich set of enablement collateral. For more information, visit Protection freescale.com/safeassure. Over-voltage • Over-current/SC • Over-temperature • Open load • MC33789 Key Features • Designed to operate 5.2 V < VPWR < 20 V, up to 40 V transients • • • • • Status Report • • • • • • • • Temperature Range Package - 40 °C to 125 °C 64 LQFP-EP Contact Sales Evaluation board to demonstrate the key features of the MC33789 MC33789 Data Sheet - Airbag System Basis Chip (SBC) w/ Power Supply and PSI5 Sensor interfaces SG1002 Selectable Switch Input Detector Suppliesr Self-protected and diagnostic capability SG187 Automotive Selector Guide Two configurable high side/low side Four PSI5 satellite sensor master System power mode control with Questions watchdog and system Power ON Reset • Supports complete airbag system 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 • LIN 2.1 physical layer interface. 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. power supply architecture, including • Auto Retry MCZ33789AE/R2 (POR) • Shut Down Order Number drivers with PWM capability • Limiting Ordering Information Safing state machine with programmable sensing thresholds • Detect • 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? 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. For more information, please visit freescale.com Freescale and the Freescale logo are trademarks of Freescale Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off. Qorivva, SafeAssure and Xtrinsic are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. The Power Architecture and Power.org word marks and the Power and Power.org logos and related marks are trademarks and service marks licensed by Power.org. © 2012 Freescale Semiconductor, Inc. Document Number: MC33789FS, Rev. 3.0