Analog Mixed Signal and Power Management MC33797 Four Channel Squib Driver IC Applications MC33797 Simplified Application Diagram • Automotive Air Bag Deployment • Automatic Seat Belt Retention • Computer Controlled Model Rocketry Igniters 33797 VPWR VIN • Remote Firing of Pyrotechnic and Firework Displays • Computer Controlled Firing of Blasting Caps for Mining and Construction VFIRE_1 FIRING CAP VFIRE_1B • Military or Police Weapon Systems VFIRE_2A 5.0 V FIRING CAP The device has the capability to be used in a standard four channel squib driver IC or in a cross-coupled state with the high and low side squib drivers located on separate squib driver ICs. Both the high and low side output drivers are protected against temporary shorts to battery or ground. The current limit threshold is set by an external resistor. Microprocessor SQB_LO VFIRE_RTN VFIRE_2B R_LIMIT_1 Overview The Four Channel Squib Driver IC is a complete squib diagnostic and deployment interface for use in automotive air bag modules. Extensive diagnostics and system control features are incorporated to provide fail-safe operation. The device contains a serial peripheral interface (SPI) compatible 8-bit interface to allow microprocessor control. SENSE VDIAG_2 VBOOST2 • Ballistic Recovery Systems SQB_HI VDIA_ VBOS1 Typical Air Bag Power Sply VDD CS CLK MISO MOSI RST FEN1 FEN_2 ENABLE ENABLE R_LIMIT_2 R_DIAG GND Performance Typical Values Output Voltage, VDD 5.0 V Firing Conditions Operating Voltage 7.0 V £ VVFIRE_XX £ 35 V 2.0 Amps, 2.0 ms @ 25 V 2.0 Amps, 0.8 ms @ 35 V ESD (HBM) ± 2000 V Control SPI Outputs 4 Operating Temperature -40 °C £ TA £ 85 °C Junction Temperature -40 °C £ TJ £ 100 °C Squib (1A, B 2A, 2B) Analog Mixed signal and Power Management Features Customer Benefits Questions • Four channel high side and low side 2.0 A FET switches • Externally adjustable FET current limiting • Adjustable current limit range: 0.8 A to 2.0 A • Individual channel current limit detection with timing duration measurement, communicated via the SPI • 8-bit SPI for diagnostics and FET switch activation • Diagnostics for high side safing sensor status • Resistance and voltage diagnostics for squibs • Squib driver IC capability to be used for cross-coupled driver firing application (allows high and low side FET switches to be located on separate squib driver ICs) • Devices available for comparison are in the Analog Product Selector Guide - SG1002 and Automotive Product Selector Guide SG187 • • • • • Are you working with automotive air bag or seat belt retaining systems? • Are you working with any type of controlled explosive devices? • Do you need to control the firing of a squib, blasting cap, or other pyrotechnic devices? • Do you need to control a firing device using an MCU? • Are diagnostic features and near fail-safe operation required? Protection Over-voltage Under-voltage Over-current/SC Lamp Simple and low-cost squib firing control Diagnostics insure reliable performance Easy interface to MCU Automotive temperature range Detect Limiting • • • • • Status Reporting • • Shutdown • • 32 SOICW/EP Ordering Information Device MC33797BPEW/R2 Temperature Range Package -40 to 85°C 32 SOICW-EP Documentation MC33797 Data sheet order number SG1002 Analog Product Selector Guide SG 187 Automotive Product Selector Guide 0.65 mm Pitch 7.5 x 11.0 mm Body 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., 2011. All rights reserved. Document Number: MC33797FS REV 4.0