MCZ33797EK

Freescale Semiconductor Technical Data Document Number: MC33797 Rev 6.0, 2/2014 Four Channel Squib Driver IC 33797 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. 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. This device is powered by SMARTMOS technology. Features • Four channel high side and low side 2.0 A FET switches • Externally adjustable FET current limiting • Adjustable current limit range: 0.8 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) SQUIB DRIVER EW SUFFIX (PB-FREE) 98ARH99137A 32-PIN SOICW Applications • Automotive air bag deployment • Automatic seat belt retention • Computer controlled model rocketry igniters • Remote firing of pyrotechnic and firework displays • Computer controlled firing of blasting caps for mining and construction • Military or police weapon systems 33797 VPWR VIN VBOS1 Typical Air Bag Power Supply VFIRE_1 FIRING CAP VFIRE_1B VFIRE_2A Microprocessor SENSE VDIAG_2 VBOOST2 5.0 V SQB_HI VDIA_ FIRING CAP SQB_LO VFIRE_RTN VFIRE_2B R_LIMIT_1 ENABLE ENABLE VDD CS CLK MISO MOSI RST FEN1 FEN_2 R_LIMIT_2 R_DIAG GND Figure 1. 33797 Simplified Application Diagram © Freescale Semiconductor, Inc., 2006 - 2014. All rights reserved. Squib (1A, B 2A, 2B) 1 Orderable Parts Table 1. Orderable Part Variations Part Number Temperature (TA) Package MC33797BPEW -40 to 85 °C 32 SOICW Notes 1. To order parts in Tape & Reel, add the R2 suffix to the part number. 33797 2 Analog Integrated Circuit Device Data Freescale Semiconductor INTERNAL BLOCK DIAGRAM SQB_LO_2A VFIRE_RTN Driver Control SQB_LO_2B SENSE_2B SQB_HI_2B VFIRE_1B VDD VDIAG_1 CLK MOSI MISO Driver Control VFIRE_1A SQB_HI_1A SENSE_1A SQB_LO_1A VFIRE_RTN SQB_LO_1B Driver Control SENSE_2A Control and Diagnostic Multiplex SQB_HI_2A CS FEN_2 FEN_1 Driver Control VFIRE_2A VDIAG_2 VFIRE_2B INTERNAL BLOCK DIAGRAM SENSE_1B SQB_HI_1B RST R_LIMIT_1 R_DIAG R_LIMIT_2 GND Figure 2. 33797 Simplified Internal Block Diagram 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 3 PIN CONNECTIONS PIN CONNECTIONS SQB_LO_1A SENSE_1A MOSI CLK SQB_HI_1A VFIRE_1A VDIAG_1 GND MISO VDD VFIRE_1B SQB_HI_1B FEN_1 R_LIMIT_1 SENSE_1B SQB_LO_1B 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 SQB_LO_2A SENSE_2A CS RST SQB_HI_2A VFIRE_2A VDIAG_2 VFIRE_RTN VFIRE_RTN R_DIAG VFIRE_2B SQB_HI_2B FEN_2 R_LIMIT_2 SENSE_2B SQB_LO_2B Figure 3. Pin Function Description Table 2. Pin Function Description Pin Pin Name Pin Function Formal Name Pin Description 1 SQB_LO_1A Output Squib Lo 1A Drain of the low side switch that connects to the low pin of Squib_1A 2 SENSE_1A Input Squib Sense 1A Used during standard applications involving a four channel squib driver IC or during cross-coupling applications involving two four channel squib driver ICs (squib driver IC #1 and squib driver IC #2). 3 MOSI Input Data Input 1 Serial data input for SPI interface. 4 CLK Input Serial Clock Serial clock input for SPI interface. 5 SQB_HI_1A Output Squib Hi 1A Drain of the high side switch that connects to the low pin of Squib_1A 6 VFIRE_1A Supply Squib Firing Supply 1A Firing supply pin for Squib_1A. 7 VDIAG_1 Input Squib Diagnostic 1A and 1A Diagnostic pin for high side safing sensor for squibs 1A and 1B and the VFIRE supply voltage. 8 GND Ground Device Ground Device ground pin for internal logic and diagnostic circuitry. 9 MISO Output Data Output 0 Serial data output for SPI interface. 10 VDD Input Logic Power Device power pin for internal logic and diagnostic circuitry. 11 VFIRE_1B Supply Squib Firing Supply 1B Firing supply pin for Squib_1B. 12 SQB_HI_1B Output Squib Hi 1B Drain of the high side switch that connects to the low pin of Squib_1B 13 FEN_1 Input FET Driver 1A and 1B Active high input signal to enable operation of the squib_1A and Squib_1BFET drivers. 14 R_LIMIT_1 Output Limit Resistor - 1A and 1B External resistor to ground is used to set current limit for Squib_1A and squib_1B FET drivers. 15 SENSE_1B Input Squib Sense 1B Used during standard applications involving a four channel squib driver IC and during cross-coupling applications involving two four channel squib driver ICs (squib driver IC #1 and squib driver IC #2). 33797 4 Analog Integrated Circuit Device Data Freescale Semiconductor PIN CONNECTIONS Table 2. Pin Function Description (continued) Pin Pin Name Pin Function Formal Name Pin Description 16 SQB_LO_1B Output Squib Lo 1B Drain of the low side switch that connects to the low pin of Squib_1B 17 SQB_LO_2B Output Squib Lo 2B Drain of the low side switch that connects to the low pin of Squib_2B 18 SENSE_2B Input Squib Sense 2B Used during standard applications involving a four channel squib driver IC and during cross-coupling applications involving two four channel squib driver ICs (squib driver IC #1 and squib driver IC #2). 19 R_LIMIT_2 Output Limit Resistor - 2A and 2B External resistor to ground is used to set current limit for Squib_2A and squib_2B FET drivers. 20 FEN_2 Input FET Driver 2A  and 2B Active high input signal to enable operation of the squib_2A and Squib_2B FET drivers. 21 SQB_HI_2B Output Squib Hi 2B Drain of the high side switch that connects to the low pin of Squib_2B. 22 VFIRE_2B Supply Squib Firing Supply 2B Firing supply pin for squib_2B. 23 R_DIAG Input Limit Resistor Diagnostic External resistor to ground is used to set the diagnostic current for squib resistance. 24 VFIRE_RTN Ground Squib Fire Power Ground Power Ground for squibs 1A, 1B, 2A, and 2B 25 VFIRE_RTN Ground Squib Fire Power Ground Power Ground for squibs 1A, 1B, 2A, and 2B 26 VDIAG_2 Supply Squib Diagnostic 2A and 2b Diagnostic pin for high side safing sensor for squibs 2A and 2B and the VFIRE supply voltage. 27 VFIRE_2A Supply Squib Firing Supply 2A Firing supply pin for squib_ 2A 28 SQB_HI_2A Output Squib Hi 2A Drain of the high side switch that connects to the low pin of Squib_2A 29 RST Input Reset Reset, Active Low 30 CS Input Chip Select Chip Select for SPI interface, Active Low 31 SENSE_2A Input Squib Sense 2A Used during standard applications involving a four channel squib driver IC or during cross-coupling applications involving two four channel squib driver ICs (squib driver IC #1 and squib driver IC #2). 32 SQB_LO_2A Output Squib Lo 2A Drain of the low side switch that connects to the low pin of Squib_2A 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 5 ELECTRICAL CHARACTERISTICS MAXIMUM RATINGS ELECTRICAL CHARACTERISTICS MAXIMUM RATINGS Table 3. Maximum Ratings All voltages are with respect to ground, unless otherwise noted. Exceeding these ratings may cause a malfunction or permanent damage to the device. Rating Symbol Value Unit VDD 7.0 V INPUT ELECTRICAL RATINGS Voltage on VDD Voltage on Input pins CS, CLK, D1, D0, FEN_1, FEN_2, RESET, R_DIAG, R_LIMIT_X VI V -0.3 to VDD + 0.3 Voltage on Squib pins SQB_HI_XX, SQB_LO_XX, SENSE_XX VVFIRE_XX -0.3 to VVFIRE + 0.3 V Voltage on pins VDIAG_X, VFIRE_XX VDIAG_X -0.3 to 35 V (1) ESD Voltage Human Body Model Machine Model V (1), (2) Maximum VVFIRE with Pulsed Output RSQUIB = 2.0 , tON = 0.8 ms, ISQUIB = 2.24 A VESD1 ±2000 VESD2 ±200 VFPULSE V 35 RSQUIB = 1.2 , tON = 0.8 ms, ISQUIB = 2.24 A 25 RSQUIB = 0.1 , tON = 0.60 ms, ISQUIB = 2.24 A 25 THERMAL RATINGS Storage Temperature Junction Temperature Ambient Continuous (Prior to Squib Deployment) t 5.0 ms (Post-squib Deployment) TSTG 155 C C TA 85 TJCONT TJDPYD 100 Peak Package Reflow Temperature During Reflow (3), (4) TPPRT Note 4 °C Thermal Resistance (Junction-to-Ambient) RJA 74 C/W 300 Notes 1 ESD1 testing is performed in accordance with the Human Body Model (CZAP = 100 pF, RZAP = 1500 ), ESD2 testing is performed in accordance with the Machine Model (CZAP = 200 pF, RZAP = 0 ). 2 3 4 5. With a nominal squib load, the FET squib driver will not enter thermal shutdown until the driver has been active for a minimum of 2.1 ms. The individual squib driver thermal shutdown will not affect other squib driver firing “ON” times. With a shorted squib load, the FET squib driver will not enter thermal shutdown until the driver has been active for a minimum of 2.1 ms. When the thermal shutdown limit is exceeded, the FET driver will turn OFF and the thermal status bit will be set to 1. The FET squib driver can be activated through the arm / fire command when the TEMPRENABLE (MIN) is reached (thermal shutdown status “0”). Nominal squib load is 2.15  ± 0.15 . Shorted squib load is 0.1  Three squib driver with RSQUIB = 0.1  conditions. Remaining squib driver conditions: RSQUIB = 1.2 , tON = 4.0 ms, ISQUIB = 2.0 A, VVDIAG_X = VVFIRE_XX = 35 V. Pin soldering temperature limit is for 10 seconds maximum duration. Not designed for immersion soldering. Exceeding these limits may cause malfunction or permanent damage to the device. Freescale’s Package Reflow capability meets Pb-free requirements for JEDEC standard J-STD-020C. For Peak Package Reflow Temperature and Moisture Sensitivity Levels (MSL), Go to www.freescale.com, search by part number [e.g. remove prefixes/suffixes and enter the core ID to view all orderable parts. (i.e. MC33xxxD enter 33xxx), and review parametrics. 33797 6 Analog Integrated Circuit Device Data Freescale Semiconductor ELECTRICAL CHARACTERISTICS MAXIMUM RATINGS Table 3. Maximum Ratings All voltages are with respect to ground, unless otherwise noted. Exceeding these ratings may cause a malfunction or permanent damage to the device. Rating OPERATING RATING Symbol Value Unit (6) FET Driver Firing Current RSQUIB = 2.0 , VSQUIBHI = 16 V, tON = 2.6 ms RSQUIB = 1.2 , VSQUIBHI = 16 V, tON = 2.6 ms RSQUIB = 0.1 , VSQUIBHI = 16 V, tON = 2.6 ms ISQUIB A 3.0 3.0 3.0 Notes 6 Operating ratings indicate conditions for which the device is intended to be functional. For guaranteed specifications and test conditions, refer to the static and dynamic electrical characteristics tables on the following pages. 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 7 ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS Table 4. Static Electrical Characteristics Characteristics noted under conditions 4.75 V  VDD  5.25 V; 7.0 V  VVFIRE_XX  35 V; VVDIAG_X = VVFIRE_XX; FEN 1 = FEN 2 = VDD; RR_LIMIT_X = 10 k ±1%, RR_DIAG = 10 k ±1%, -40 C  TA  +85 C, GND = 0, unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max Unit VDD 4.75 5.0 5.25 V Leakage Current at Minimum High Side Driver Breakdown Voltage IDHSD – 39 100 µA Leakage Current at Minimum Low Side Driver Breakdown Voltage IDLSD – 65 100 µA INPUT VOLTAGE (VDD) Input Voltage FET DRIVERS High Side Driver Current Limit Range Set via Rlimit Resistor with Low Battery Condition tON  4.0 ms, RR_LIMIT_X = 10 k, 5.0 V VVFIRE  7.0 V, RSQUIB = 2.0  High Side Driver Low Current Limit Range Set via Rlimit Resistor tON  2.6 ms, RR_LIMIT_X = RL=4.32 k7.0 V  VVFIRE  35 V IHS(LBAT) IHS(NOM) High Side Driver High Current Limit Range Set via Rlimit Resistor tON  0.8 ms, RR_LIMIT_X = RL=45.3 k7.0 V  VVFIRE  35 V IHS(HISET) High Side Driver Current Limit Detect Threshold (7) 7.0 V  VVFIRE  35 V Driver ON Resistance (per FET) VVFIRE = 5.0 V, ILOAD = 0.5 A VDD Operating Current Standby (Diagnostics off, SPI “OFF”) No Fire—Worst Case Diagnostics ($83/$2F Command Active) Firing (with All FET Drivers “ON”) VFIRE Quiescent Current With Diagnostics Off (8) 1.09 1.4 2.9 0.81 0.93 1.03 IHS(LOSET) High Side Driver Nominal Current Limit Range Set via Rlimit Resistor tON  2.6 ms, RR_LIMIT_X = RL=10 k7.0 V  VVFIRE  35 V Low Side Drivers Current Limit 7.0 V  SQLO < 16 V SQLO = 16 V A A A 1.21 1.4 1.54 1.76 2.0 2.24 2.1 2.24 2.47 2.65 3.0 3.14 IHS x 0.85 – IHS x 1.0 – – 1.0 – – 2.0 15 5.0 18.5 – 4.3 6.0 A ILS A IMEAS A  RDS(ON) IDD mA IRRE VDIAG Current During Squib Diagnostics With Squib Resistance Diagnostics Active IRRE VFIRE Operating Current During Firing Excluding Firing Current, IHS = 2.0 A IRRE VDIAG Operating Current During Firing Per VDIAG pin, excluding Firing Current, IHS = 2.0 A IRRE µA 22 34 55 32 37 43 – 1.8 11 – 140 200 mA mA µA Notes 7 Guaranteed by design 8 VFIRE quiescent current includes any leakage current through squib. 33797 8 Analog Integrated Circuit Device Data Freescale Semiconductor ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS Table 4. Static Electrical Characteristics (continued) Characteristics noted under conditions 4.75 V  VDD  5.25 V; 7.0 V  VVFIRE_XX  35 V; VVDIAG_X = VVFIRE_XX; FEN 1 = FEN 2 = VDD; RR_LIMIT_X = 10 k ±1%, RR_DIAG = 10 k ±1%, -40 C  TA  +85 C, GND = 0, unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol VFIRE1A / VFIRE2A Current During High Side Safing Sensor Diagnostics (Command $CO) Per VFIREXA pin, with High Side Safing Sensor Diagnostic active IRRE VFIRE1B / VFIRE2B Current During High Side Safing Sensor Diagnostics (Command $CO) IRRE Maximum Allowable External Capacitance to Ground Per Squib pin SQB_LO and SQB_HI (9) Maximum Allowable External Resistance to Ground During Firing (9) VFIRE_RTN pin to Ground Individual FET Driver Thermal Shutdown (9), (10) FET Driver Thermal Shutdown Re-enable Threshold After Drive Cool down (9), (10) Max 350 µA 22 32 55 0.3 2.0 3.8 mA IQVFIRETOTAL µA 90 135 180 – – 0.12 – – 0.15 160 – 190 90 – 110 CSMAX µF  RSMAX TSD TREN Unit 415 IRRE Either VFIRE!B or VFIRE2B Diagnostic active VFIRE Quiescent Current - Total All VFIRE pins measured together, with Diagnostics Off Typ µA 260 Per VFIREXB pin, with High Side Safing Sensor Diagnostic active VFIRE1B / VFIRE2B Current During VFIRE Diagnostics (Command $C5) Min C C FET DRIVERS HIGH AND LOW SIDE DRIVER TRANSISTOR STATUS /DIAGNOSTICS ($82, $83 COMMANDS) Voltage Transistor Test Threshold for High Side Driver Transistor VTRANTST1 High Side Driver Current Limit During High Side Driver Transistor Diagnostics 15 V VVFIRE_XX 35 V ITRANTST1 Voltage Transistor Test Threshold for Low Side Driver Transistor VTRANTST2 Low Side Driver Current Limit During Low Side Driver Transistor Diagnostics 15 V VVFIRE_XX 35 V ITRANTST2 5.5 6.0 6.5 V mA 2.0 10 50 1.0 1.4 2.0 V mA 2.0 10 50 IFEN -25 -40 -50 A Logic Low Level VFEN(LO) 0.0 2.5 0.35 x VDD V Fire Enable Pin Logic High Level VFEN(HI) 0.65 x VDD 2.5 1.0 x VDD V FEN INPUT PIN (FEN_1 AND FEN_2) Internal Current Pull-down Notes 9 Guaranteed by design. 10 With a nominal squib load, the FET squib driver will not enter thermal shutdown until the driver has been active for a minimum of 2.1 ms. The individual squib driver thermal shutdown will not affect other squib driver firing ON times. With a shorted squib load, the FET squib driver will not enter thermal shutdown until the driver has been active for a minimum of 2.1 ms. When the thermal shutdown limit is exceeded, the FET driver will turn OFF and the thermal status bit will be set to 1. The FET squib driver can be activated through the arm / fire command when the TEMPRENABLE (MIN) is reached (thermal shutdown status “0”). Nominal squib load: 2.15  ± 0.15 . Shorted squib load: 0.1  33797 Analog Integrated Circuit Device Data Freescale Semiconductor 9 ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS Table 4. Static Electrical Characteristics (continued) Characteristics noted under conditions 4.75 V  VDD  5.25 V; 7.0 V  VVFIRE_XX  35 V; VVDIAG_X = VVFIRE_XX; FEN 1 = FEN 2 = VDD; RR_LIMIT_X = 10 k ±1%, RR_DIAG = 10 k ±1%, -40 C  TA  +85 C, GND = 0, unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max Unit VDDRST – – 4.1 V IRST -6.0 -10 -15 A RST Logic Low Level VRST(LO) 0.0 2.5 0.35 x VDD V RST Logic High Level VRST(HI) 0.65 x VDD 2.5 1.0 x VDD V RST INPUT PIN (ACTIVE LOW) (11) System Reset Threshold Internal Current Pull-down SQUIB DIAGNOSTICS ($D0–$D3 COMMANDS) (12) Diagnostic Current Through Squib (13) IDIAG 30 34 40.5 mA Resistance Threshold 1 (13) RTH1 1.2 1.4 1.6  Resistance Threshold 2 (13) RTH2 1.6 1.8 2.1  Resistance Threshold 3 (13) RTH3 2.1 2.4 2.6  (13) RTH4 2.6 2.9 3.2  Resistance Threshold 5 (13) RTH5 3.3 3.7 4.4  (13) RTH6 4.6 5.4 6.0  Resistance Threshold 7 (13) RTH7 5.7 6.5 7.1  (13) RTH8 6.7 7.8 8.5  Resistance Threshold 4 Resistance Threshold 6 Resistance Threshold 8 SQUIB SHORT-TO-BATTERY / GROUND DIAGNOSTICS AND SQUIB HARNESS SHORT-TO-BATTERY / GROUND DIAGNOSTICS WITH AN OPEN SQUIB ($C1, $C3 COMMANDS) Voltage Threshold for SQB_LO and SQB_HI Shorted to VPWR 7.0 V VVDIAG_X  35 V VTHSB Voltage Threshold for SQB_LO and SQB_HI Shorted to Ground 7.0 V VVDIAG_X  35 V VTHSG Current Sink Shorts Measurements I_SQB_LO_XX 1.0 V  SENSE_XX  16 V, Typical = 800 A (14) Current Source Shorts Measurements I_SQB_HI_XX (14) 1.0 V  SENSE_XX  16 V, 7.0 V  VVDIAG_X  35 V Voltage Threshold for SQB_LO or SQB_HI Shorted to VPWR with an Open Squib using $C3 Command RSQUIB = Open V 5.7 6.0 6.4 V 1.3 1.4 1.6 -500 -800 -900 1.7 3.5 3.7 A ISINKSHRTS ISOURSHRTS mA VTHSB_SO V 5.75 – 6.79 Notes 11 Reset Bar range of operation: The minimum system reset bar threshold/active will be set to “0” for a value of VDD 4.1 V. 12 13 By changing the R_DIAG resistor value, the resistance thresholds can be varied in a linear relationship.The R_DIAG resistance can be changed by ±10% to shift the thresholds by ±10%. Design goal for resistance threshold change is ±15%. R_DIAG threshold limit may have to be changed to accommodate ±15% change. Example: Shifting the R_DIAG resistance value ±10%, the resistance threshold will change by ±10%. Refer to Table 5, page 13. RR_DIAG = 10 k ±1.0% 14 XX = 1A, 1B, 2A, or 2B. 33797 10 Analog Integrated Circuit Device Data Freescale Semiconductor ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS Table 4. Static Electrical Characteristics (continued) Characteristics noted under conditions 4.75 V  VDD  5.25 V; 7.0 V  VVFIRE_XX  35 V; VVDIAG_X = VVFIRE_XX; FEN 1 = FEN 2 = VDD; RR_LIMIT_X = 10 k ±1%, RR_DIAG = 10 k ±1%, -40 C  TA  +85 C, GND = 0, unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max Unit Voltage Threshold for SQB_LO or SQB_HI Shorted to Ground with an Open Squib using $C3 Command RSQUIB = Open VTHSG_SO 1.3 1.8 2.0 V DIAGNOSTICS FOR SQUIB CONTINUITY BETWEEN SENSE_XX AND SQB_LO_XX ($C2 COMMAND) Current Threshold for SQUIB_LO_1A, 1B, 2A, and 2B Continuity Check for Standard and Cross-coupled Conditions ($C2) SQUIB_LO_XXCONT (15) 7.0 V  VVDIAG_X  35 V A ITHSQB CON 150 – 350 1.0 1.4 2.0 DIAGNOSTICS FOR SQUIB SHORT BETWEEN FIRING LOOPS ($E0–$E3, $E8 COMMANDS) Voltage Threshold for Standard Squib Connection 7.0 V  VVDIAG_X  35 V VTHSQBNOM Voltage Threshold for SQUIB_X Shorted to SQUIB_Y (1 or More Shorted Conditions) V VTHSSQB Short Between Squib Lines (Loops) (SQUIB_XX_SSQB_YY) (16) V 1.0 1.4 2.0 VDIAG SUPPLY DIAGNOSTICS ($C0 COMMAND) VDIAG Supply Voltage High Threshold VDHI 15 17 19.0 V VDIAG Supply Voltage Low Threshold VDLO 5.7 6.5 7.2 V VFIRE Supply Voltage High Threshold VFDHI 15 17 19.0 V VFIRE Supply Voltage Low Threshold VFLO 5.7 6.5 7.2 V VFIRE SUPPLY DIAGNOSTICS VFIRE_1B AND VFIRE_2B ($C5COMMAND) VDIAG SUPPLY DIAGNOSTICS VDIAG_1 AND VDIAG_2 (ADDITIONAL VOLTAGE THRESHOLDS) ($C6 COMMAND) VDIAG Supply Voltage Threshold 4 VVDIAG_X V4 29.8 32.8 38.5 V VDIAG Supply Voltage Threshold 3 VVDIAG_X V3 25.5 27.7 30.5 V VDIAG Supply Voltage Threshold 2 VVDIAG_X V2 20.5 22.6 26.5 V VDIAG Supply Voltage Threshold 1 VVDIAG_X V1 16 18.4 21.0 V R_RTN1 Short-to-Ground Threshold (Open Ground Connection) RRTN1 0.15 – 0.6  R_RTN2 Short-to-Ground Threshold (Open Ground Connection) RRTN2 0.15 – 0.6  4.1 5.1 6.1 VFIRE_RTN DIAGNOSTICS ($C9 COMMAND) HIGH SIDE SAFING SENSOR DIAGNOSTICS ($C0 COMMAND) R_HS Valid Resistor Range 15 V VVDIAG_X 35 V RHS R_HS Open Threshold 15 V VVDIAG_X 35 V RHSO k k 6.1 7.2 9.0 Notes 15 XX = 1A, 1B, 2A, or 2B 16 XX and YY = 1A, 1B, 2A, or 2B 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 11 ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS Table 4. Static Electrical Characteristics (continued) Characteristics noted under conditions 4.75 V  VDD  5.25 V; 7.0 V  VVFIRE_XX  35 V; VVDIAG_X = VVFIRE_XX; FEN 1 = FEN 2 = VDD; RR_LIMIT_X = 10 k ±1%, RR_DIAG = 10 k ±1%, -40 C  TA  +85 C, GND = 0, unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max Unit R_HS Short Threshold RHSS 2.8 – 4.1 k VFIRE_XA & VFIRE_XB Current during High Side Safing Test at Open Threshold VFIRE_1A & VFIRE_1B or VFIRE_2A & VFIRE_2B I1HSO VFIRE_XA & VFIRE_XB Current during High Side Safing Test at Short Threshold VFIRE_1A & VFIRE_1B or VFIRE_2A & VFIRE_2B I1HSS A 270 360 410 A 287 385 439 HIGH SIDE SAFING SENSOR DIAGNOSTICS WITH 1 SAFING SENSOR IN FIRING PATH CONNECTED TO VFIRE_1A AND VFIRE_2A PINS (GUARANTEED BY DESIGN) ($C0 COMMAND) Total VFIRE_XX Current during High Side Safing Test at Open Threshold VFIRE_1A, VFIRE_1B, VFIRE_2A & VFIRE_2B pins I2HSO Total VFIRE_XX Current during High Side Safing Test at Short Threshold VFIRE_1A, VFIRE_1B, VFIRE_2A & VFIRE_2B pins I2HSS R_HS Valid Resistor Range 15 V VVDIAG_X 35 V R2HS R_HS Open Threshold 15 V VVDIAG_X 35 V R2HSO R_HS Short Threshold 15 V VVDIAG_X 35 V R2HSS A 574 705 848 605 748 892 A k 2.10 – 2.93 2.93 3.35 4.43 1.14 1.61 2.10 RRL 4.32 – 45.3 k R_LIMIT Open Threshold (“Out of Range Threshold”) RRLO 60 76 105 k R_LIMIT Short-to-Ground Threshold (“Out of Range Threshold”) RRLS 2.82 3.5 4.31 k Maximum External Capacitance to Ground CRL – – 20 pF RRD 8.0 – 13 k R_DIAG Open Threshold (“Out of Range Threshold”) RRDO 13 23 60 k R_DIAG Short-to-Ground Threshold (“Out of Range Threshold”) RRDS 3.0 5.4 8.0 k Maximum External Capacitance to Ground CRD – – 20 pF k k R_LIMIT RESISTOR DIAGNOSTICS ($C8 COMMAND) R_LIMIT Valid Resistor Range R_DIAG RESISTOR DIAGNOSTICS ($C8 COMMAND) (17) R_DIAG Valid Resistor Range Notes 17 By changing the R_DIAG resistor value, the resistance thresholds can be varied by a linear relationship.The R_DIAG resistance could be changed by ±10% to shift the thresholds by ±10%. Design goal for resistance threshold change is ±15%. R_DIAG threshold limit may have to be changed to accommodate ±15% change. Example: Shifting the R_DIAG resistance value ±10%, the resistance threshold will change by ±10%. Refer to Table 5. 33797 12 Analog Integrated Circuit Device Data Freescale Semiconductor ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS Table 4. Static Electrical Characteristics (continued) Characteristics noted under conditions 4.75 V  VDD  5.25 V; 7.0 V  VVFIRE_XX  35 V; VVDIAG_X = VVFIRE_XX; FEN 1 = FEN 2 = VDD; RR_LIMIT_X = 10 k ±1%, RR_DIAG = 10 k ±1%, -40 C  TA  +85 C, GND = 0, unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25°C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max 0.0 – 0.2 0.7 – 1.0 Unit SERIAL INTERFACE Output Logic Low Level (D0) ISINK = -800 µA VOLOW Output Logic High Level (D0) ISOURCE = 800 µA VOHIGH Input Logic Threshold (D1, CS, CLK) VLTHR 0.35 – 0.65 x VDD D1 Pull-down Current ID1 -6.0 -10 -15 µA CLK Pull-down Current ICLK -6.0 -10 -15 µA CS Pull-up Current ICSBAR 10 20 30 µA HI-Z Leakage (D0) IHI-Z – – ±10 µA x VDD x VDD Table 5. Resistance Range vs. R_DIAG IDIAG (NOM) RTH1 Min / Max RTH2 Min / Max RTH3 Min / Max RTH4 Min / Max RTH5 Min / Max RTH6 Min / Max RTH7 Min / Max RTH8 Min / Max 8.0 k (-20%) 41 0.9 / 1.3 1.2 / 1.7 1.6 / 2.1 2.0 / 2.6 2.6 / 3.6 3.6 / 4.8 4.5 / 5.7 5.3 / 6.8 9.0 k (-10%) 38 1.0 / 1.4 1.4 / 1.9 1.9 / 2.3 2.3 / 2.9 2.0 / 4.0 4.1 / 5.4 5.1 / 6.4 6.0 / 7.7 10.0 k 35 1.2 / 1.6 1.6 / 2.1 2.1 / 2.6 2.6 / 3.2 3.3 / 4.4 4.6 / 6.0 5.7 / 7.1 6.7 / 8.5 11.0 k (+10%) 32 1.3 / 1.8 1.8 / 2.3 2.3 / 2.9 2.9 / 3.6 3.6 / 4.9 5.0 / 6.6 6.2 / 7.8 7.4 / 9.4 12.0 k (+20%) 29 1.4 / 1.9 1.9 / 2.5 2.5 / 3.1 3.1 / 3.9 3.9 / 5.3 5.5 / 7.2 6.8 / 8.6 8.0 / 10.2 13.0 k (+30%) 26 1.5 / 2.1 2.1 / 2.7 2.7 / 3.4 3.4 / 4.2 4.2 / 5.8 6.0 / 7.8 7.4 / 9.3 8.7 / 11.1 R_DIAG 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 13 ELECTRICAL CHARACTERISTICS DYNAMIC ELECTRICAL CHARACTERISTICS DYNAMIC ELECTRICAL CHARACTERISTICS Table 6. Dynamic Electrical Characteristics Characteristics noted under conditions 4.75 V  VDD  5.25 V; 7.0 V  VVFIRE_XX  35 V; VVDIAG_X = VVFIRE_XX; FEN 1 = FEN 2 = VDD; RR_LIMIT_X = 10 k ±1%, RR_DIAG = 10 k ±1%, -40 C  TA  +85 C, GND = 0, unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25 °C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max Unit tCYC 200 – – ns 73 – – 73 – – – – 20 – – 20 – – 20 – – 20 73 – – 73 – – 30 – – 30 – – SERIAL INTERFACE CLK Cycle Time (1/FCLK) (18) (18) CLK High Time VCLK > VDD x 70% tHI CLK Low Time (18) VCLK < VDD x 20% tLO Clock Rise Time (18) VCLK = 20% VDD to 70% VDD, CLOAD = 100 pF tRISE Clock Fall Time (18) VCLK = 70% VDD to 20% VDD, CLOAD = 100 pF tFALL Data Out Rise Time (19) VDO = 20% VDD to 70% VDD, CLOAD = 100 pF tR Data Out Fall Time (19) VDO = 70% VDD to 20% VDD, CLOAD = 100 pF tF Chip Select Setup Time (19) ns ns ns ns ns tSU D1 Valid Before CLK  Data In Hold Time (19) D1 Hold Time After CLK  tH Data Out Access Time (19) tA CSB  to D0 Valid Data Out Disable Time CSB  to D0 HI-Z ns tLAG CLK  Before CSB  Data In Setup Time (19) ns tLEAD CSB  Before CLK  Chip Select Hold Time (19) ns (19) Data Out Valid Time (19) CLK  to D0 Valid, CLOAD = 100 pF (19) Data Out Hold Time D0 held After CLK  Diagnostic Delay Time (Between Two Successive Commands) ns ns ns – – 73 – – 73 tDIS ns tV ns – – 75 0.0 – – 2.5 – – tHO tDIAG ns s Notes 18 Determined by Design 19 Guaranteed by Characterization 33797 14 Analog Integrated Circuit Device Data Freescale Semiconductor ELECTRICAL CHARACTERISTICS DYNAMIC ELECTRICAL CHARACTERISTICS Table 6. Dynamic Electrical Characteristics (continued) Characteristics noted under conditions 4.75 V  VDD  5.25 V; 7.0 V  VVFIRE_XX  35 V; VVDIAG_X = VVFIRE_XX; FEN 1 = FEN 2 = VDD; RR_LIMIT_X = 10 k ±1%, RR_DIAG = 10 k ±1%, -40 C  TA  +85 C, GND = 0, unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25 °C under nominal conditions, unless otherwise noted. Characteristic Symbol Min Typ Max Unit FET DRIVERS Turn-On Delay Time CS  to 80% IHS tON Turn-Off Delay Time CS  to 20% IHS tOFF Diagnostic Timing / Resolution tRESOLUTION 5.0 V  VVDIAG_X  35 V, IHS  IMEAS, 0 s tMEASURE_TIME  6.375 ms,  CSQUIB_HI = 0.12 µF, CSQUIB_LO = 0.12 µF µs – – 72 – – 10 µs µs 21.25 25 28.75 DIAGNOSTIC DELAY TIME Squib Resistance Diagnostic Delay Time (20) From CSB  Until Transistor Test Results Are Valid, CSQUIB_HI = 0.12 µF, CSQUIB_LO = 0.12 µF (20) s tDIAG1 – Squib Open / Short Diagnostic Delay Time From CSB  Until Squib Open / Short Diagnostic Results Are Valid,  CSQUIB_HI = 0.12 µF, CSQUIB_LO = 0.12 µF tDIAG2 VDIAG Supply Diagnostic Delay Time From CSB  until VDIAG Diagnostic Results Are Valid (20) tDIAG4 VFIRE Supply Diagnostic Delay Time (20) 15 V  VVDIAG_X  35 V, From CSB  Until High Side Safing Sensor Diagnostic Results Are Valid, CVDIAG < 0.015 µF tDIAG6 High Side Safing Sensor Diagnostic Delay Time (20) 15 V  VVDIAG_X  35 V, From CSB  Until High-Side Safing Sensor Diagnostic Results Are Valid, CVDIAG < 0.015 µF tDIAG7 – – 3000 – – 100 s s (20) VFIRE_RTN Diagnostic Delay Time From CSB  Until VFIRE_RTN Diagnostic Results Are Valid (20) – 500 s – FET Drivers High and Low Side Driver Transistor Diagnostic Delay Time 15 V  VVDIAG_X  35 V, From CSB  Until Transistor Test Results Are Valid, CSQUIB_HI = 0.12 µF, CSQUIB_LO = 0.12 µF, CVDIAG < 0.015 µF 300 s – (20) – – 500 s tDIAG9 – – 1000 s tDIAG10 Squib Continuity Diagnostic Delay Time From CSB  Until VTHSQBCON Diagnostic Results Are Valid tDIAG11 Squib Short Between Firing Loops Diagnostic Delay Time From CSB  Until VTHSSQB Diagnostic Results Are Valid (20) tDIAG12 – – 300 – – 3000 s s – – 3000 12 14 16 FEN INPUT PIN Minimum Pulse Width FENFILTER s Notes 20 Guaranteed by Characterization 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 15 ELECTRICAL CHARACTERISTICS TIMING DIAGRAMS TIMING DIAGRAMS Chip Select (/CS) CS 80% IHS 20% tON tOFF Figure 4. Driver Timing Diagram CS CLK MISO MSB 6 5 4 3 2 1 LSB MOSI MSB 6 5 4 3 2 1 LSB Figure 5. Freescale SPI CS CLK MISO MSB 6 5 4 3 2 1 LSB MOSI MSB 6 5 4 3 2 1 LSB Figure 6. Alternative SCI Mode 33797 16 Analog Integrated Circuit Device Data Freescale Semiconductor FUNCTIONAL DESCRIPTION INTRODUCTION FUNCTIONAL DESCRIPTION INTRODUCTION 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 for microprocessor control. This interface allows the microprocessor to set up and read back the results of all internal diagnostic functions. Squib resistance level, along with possible shorts-to-battery or ground, open ground connections, or shorts between squib firing loops, are included in the diagnostic set. Additionally, the squib supply voltage levels can be checked and the low side fire return can be checked for an open condition (open ground connection). The SPI interface, along with the additional FEN pin, is used to arm and fire a selected squib. The device has the capability to be used in a standard fourchannel 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 side and low side output drivers are protected against temporary shorts to battery or ground. The current limit threshold is set by an external resistor. FUNCTIONAL PIN DESCRIPTION INTRODUCTION DEVICE GROUND (GND) In this section references are made to XX; e.g., in SENSE_XX, SQB_LO_XX, and SQB_LO_XX_CONT. In these and similar instances, XX denotes 1A, 1B, 2A, and 2B. Device ground pin for internal logic and diagnostic circuitry. SERIAL CLOCK (SCLK) Serial clock input for SPI interface. Data on the D1 pin is clocked into the device on the rising edge. Data is clocked out of the device via the D0 pin on the falling edge. Default state is low with no connection. CHIP SELECT (CS) Chip select for SPI interface. Active low. On rising edge, data shifted into the shift register is internally latched. On falling edge, diagnostic results are latched into shift register. Default state is high with no connection. MASTEROUT/SLAVE IN (MOSI) Serial data input to 33797 SPI interface. Default state is low with no connection. MASTER IN/SLAVE OUT (MISO) DEVICE POWER (VDD) Device power pin for internal logic and diagnostic circuitry. RESET (RST) Reset Bar. Active low. With low input signal the internal functions of the squib driver IC are disabled and all data in the serial interface shift registers is cleared. Default state is low with no connection. LIMIT RESISTOR - DIAGNOSTIC (R_DIAG) External resistor to ground is used to set the diagnostic current for squib resistance. LIMIT RESISTOR 1A AND 1B (R_LIMIT_1) External resistor to ground is used to set current limit for squibs 1A and 1B FET drivers. LIMIT RESISTOR 2A AND 2B (R_LIMIT_2) Serial data output from 33797 SPI interface. External resistor to ground is used to set current limit for squibs 2A and 2B FET drivers. FET DRIVER 1A AND 1B (FEN_1) SQUIB DIAGNOSTIC 1A AND 1B (VDIAG_1) Active high input signal to enable operation of squibs 1A and 1B FET drivers. All diagnostic functions are available while pin is low. Default state is low with no connection. FET DRIVER 2A AND 2B (FEN_2) Active high input signal to enable operation of squibs 2A and 2B FET drivers. All diagnostic functions are available while pin is low. Default state is low with no connection. Diagnostic pins for the high side safing sensors for squibs 1A and 1B, as well as the VFIRE supply voltage. SQUIB DIAGNOSTIC 2A AND 2B (VDIAG_2) Diagnostic pins for the high side safing sensors for squibs 2A and 2B, as well as the VFIRE supply voltage. 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 17 FUNCTIONAL DESCRIPTION FUNCTIONAL PIN DESCRIPTION SQUIB SENSE XX (SENSE_XX) The Sense pins are used exclusively for diagnostics related to the squib, driver FETs, or harness. Commands using the Sense pins include: • C1, C2, C3, C9 • D • E • E9 • 82/1x • 83/2x Independent of the system configuration, normal or cross coupled, the Sense pin, xx and SquibHi, xx of a single IC are always connected to the same squib with the SquibHi pin connected to the high pin of the squib and the Sense pin connected to the low pin of the squib. A cross coupled configuration is achieved by only cross coupling the squib low pins. See Figure 7 and Figure 8. STANDARD APPLICATIONS In the standard mode, the $C2 (SQUIB_LO_XX_CONT) command will be used to check continuity of the low side driver from the SQB_LO_XX pin to the high side driver FET (see Figure 6). CROSS-COUPLED APPLICATIONS Used during cross-coupling applications involving two four channel squib driver ICs (squib driver IC #1 and squib driver IC #2). SENSE_XX pins from squib driver IC #1 are connected to their respective squib minus pins (Squib Low / SQB_LO_XX) from squib driver IC #2 (Figure 8). SENSE_XX pins are used to feed diagnostic signals back to squib driver IC #1 for determining squib resistance, short-tobattery/ground, and squib loop-to-loop short conditions. During a fire event, the fire current passes from squib driver IC #1 high side driver though the squib to squib driver IC #2 low side driver (Figure 8). In the cross-coupled mode, the squib driver IC #2 $C2 (SQUIB_LO_XX_CONT) command will be used to check continuity of the low side driver from the SQB_LO_XX pin to the low side driver FET. DESIGN NOTES configuration, most diagnostics are unaffected and are single commands except for $C2 Low Side FET Continuity and $E Harness Shorts, and 83/2x Low Side FET test. This command must be sent to each IC to be executed. For these three diagnostics, two commands are required because the forcing function and sensing function are on separate ICs. Harness Shorts Diagnostics: Force using $E on IC#1, Sense $E8 on IC2 Low Side FET Continuity: Force using $C1 on IC#1, Sense using $C2 on IC#2 Low Side FET Test: Force using $C1 on IC#1, Sense using $C2 on IC#2 An active 600 A current sink is located in the SENSE_XX pin. The sink current is used to pull the charge off of the external EMC / filter caps after a diagnostic measurement has been made. SQUIB HI XX (SQB_HI_XX) Squib high pins for squibs 1A, 1B, 2A, and 2B. These pins are connected to the sources of the high side FET drivers, as well as the diagnostic circuitry. SQUIB LOW XX (SQB_LO_XX) Squib low pins for squibs 1A, 1B, 2A, and 2B. These pins are connected to the drains of the low side FET drivers, as well as the diagnostic circuitry. SQUIB FIRING SUPPLY XX (VFIRE_XX) Firing supply pins for squibs 1A, 1B, 2A, and 2B. These pins are connected to the drains of the high side FET drivers. Feedback for high side safing for squibs 1A and 1B will be referenced from VFIRE_1A and squibs 2A and 2B from VFIRE_2A. For high side safing, VFIRE_1B should be connected to VFIRE_1A pin and VFIRE_2B to VFIRE_2A pin. SQUIB FIRE POWER GROUND (VFIRE_RTN) Return for squibs 1A, 1B, 2A AND 2B. The pins are tied to the source pins of both low side FET drivers, as well as the diagnostic circuitry. The RTN pins are tied internally. Diagnostics always have the form of a forcing function and a measurement or sense function. In a cross couple 33797 18 Analog Integrated Circuit Device Data Freescale Semiconductor FUNCTIONAL DESCRIPTION FUNCTIONAL PIN DESCRIPTION VBOOST Dri ver Control 1A VFIRE CS1 SPI Interface + Squib 1 SENSE_1A - SQUIB IC #1 $C2 Command checks this Figure 7. Standard Squib Firing VBOOST CS1 SPI Interface CS2 Dri ver Control 1A VFIRE + Squib 1 SENSE_1A Squib 2 SQUIB ASIC #1 Dri ver Control VFIRE + SENSE_1A - SQUIB ASIC #2 $C2 Command checks this Figure 8. Cross-coupled Squib Firing 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 19 FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES INTRODUCTION In this section references are made to XX; e.g., in SQB_HI_XX, SQB_LO_XX, and SENSE_XX pins. SQB_HI_XX refers to SQB_HI_1A, SQB_HI_1B, SQB_HI_2A or SQB_HI_2B, SQB_LO_1A, etc. SERIAL INTERFACE An 8-bit shift register is provided for communication through the serial port to a microprocessor. The four wire SPI interface is used to read from, and write to, the shift register. Data written to the shift register will control the firing of the FET switches or select a diagnostic mode. Data is sequentially shifted into and out of the shift register, most significant bit first. Data read from the shift register will contain the results of the diagnostic mode selected in the previous 8-bit write. If a NOP command is written, all diagnostic modes are cleared and the data in the shift registers will be read out. With any undefined commands, all diagnostic modes are cleared and the data in the shift registers will be read out. All functions are set when CS goes high. All diagnostic commands are cleared on the next valid SPI command. SPI INTERFACE INTEGRITY CHECK The $96 command with corresponding $69 return byte during the next 8-bit write is used as an echo function to diagnose the SPI integrity (refer to Table 9). The Diagnostic Data Out bits not containing data are set to zero. Only 8-bit words will be accepted. Any words that are 7 bits or 9 bits will be ignored or cleared. The second byte for command programming will be treated as a NOP if any FET is firing. The programming commands must be sequential or they will be treated as a NOP. The four channel squib driver IC is a slave peripheral device designed to interface to a Freescale SPI or other serial peripheral interface. Data is read on the rising edge of CLK, and data is transferred out on the rising edge of CLK. On the falling edge of CS, the IC configures itself for one of two SPI modes. If CLK is low, the IC will configure itself to be in Freescale SPI mode (see Figure 5). If CLK is high, the IC will configure itself to be in an alternative SCI mode (see Figure 5). In both cases, data is still read off the rising edge and transferred off the falling edge of the CLK. When the IC is deselected (CS goes high), then D0 is a high-impedance output. Response bit 7 of command $C8 (refer to Table 8, page 24) is hard-wired to “1” or “0” to identify the squib IC as a four or two channel squib driver IC. When a $C8 command is issued for the four channel squib driver IC, the response bit 7 is set to a “0”. When a $C8 command is issued for the two channel squib driver IC, the response bit 7 is set to a “1”. STANDARD SQUIB IC FUNCTION The standard squib IC application utilizes the high and low side squib drivers from the same squib driver ICs (see Figure 6, Standard Squib Firing). The SENSE_XX (1A, 1B, 2A, 2B) pin is connected to SQB_LO_XX (1A, 1B, 2A, 2B). Squib diagnostics are conducted using this pin. In the standard mode, the $C2 (SQUIB_LO_XX_CONT) command will be used to check continuity of the low side driver from the SQB_LO_XX pin (1A, 1B, 2A, 2B) to the low side driver FET (Figure 6). The low side driver continuity is checked during the continuity test. The driver continuity information will be cleared after the information is transmitted on the next valid SPI command. EXAMPLE—STANDARD SQUIB COMMAND SPI SEQUENCE FROM MICROCONTROLLER TX: Request squib short-to-battery / GND diagnostic measurement ($C1). RX: Previous executed command information. TX: Request squib 1A resistance measurement ($D0–$D3). RX: Receive results from short-to-battery / GND diagnostics. TX: Request squib 1B resistance measurement  ($D0–$D3). RX: Receive measured squib 1A resistance information. TX: Request squib 2A resistance measurement  ($D0–$D3). RX: Receive measured squib 1B resistance information. TX: Request squib 2B resistance measurement  ($D0–$D3). RX: Receive measured squib 2A resistance information TX: Request continuity command ($C2). RX: Receive measured squib 2B resistance information TX: Request another command sequence. RX: Receive low side driver 1A, 1B, 2A, and 2B continuity information. Latches will be cleared after data transferred from the squib IC (clear on rising edge of chip select). TX: Request loop-to-loop short command ($E0–$E3) RX: Previous executed command information. 33797 20 Analog Integrated Circuit Device Data Freescale Semiconductor FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES TX: Request another command sequence. RX: Receive loop-to-loop results from test. TX: Run another command on the same squib IC #1. RX: Receive measured squib 1A resistance information. CROSS-COUPLED SQUIB IC FUNCTION TX: Squib IC #1 request continuity command ($C2). RX: Previous executed command information. The cross-coupled application utilizes the high and low side squib drivers from two different squib driver ICs (see Figure 8, Cross-Coupled Squib Firing, page 19.) Through the SPI interface, the squib IC will maintain the capability to conduct standard diagnostics (short-to-battery, short-toground, short between squibs, and squib diagnostics) between two different squib ICs. The squib IC must maintain the capability to fire the squib drivers with the ARM and FIRE command in either cross-coupled or single IC applications. When the firing squib driver IC is used in cross-coupled applications, the low side squib driver must be activated prior to activating the high side squib driver. Cross-coupling the high and low side squib driver from two different squib driver ICs must be done without interfering with standard squib operations when the squib IC is used in an application where the high and low side squib drivers are located on the same IC. All remaining diagnostic functions will operate standard in either a cross-coupled or single IC applications. These functions include RR_DIAG, RR_LIMIT_X, high side, VVFIRE_XX, VVFIRE_RTN, VTRANSTX, squib current timing measurement, and FEN_1 and FEN_2 diagnostics. The SENSE_1A (1B, 2A, or 2B) pin squib IC #1 is connected to SQB_LO_1A (1B, 2A, or 2B) pin squib driver IC #2 and is used to feed the diagnostic signal for determining squib resistance and short-to-battery / ground conditions (see Figure 8, page 19). During a fire event, the fire current passes from squib driver IC #1 high side driver though the squib to squib driver IC #2 low side driver. In the crosscoupled mode, the squib driver IC #2 $C2 (SQUIB_LO_1A_CONT, [1B, 2A, or 2B]) command will be used to check continuity of the low side driver from the SQB_LO_1A (1B, 2A, or 2B) pin to the low side driver FET. The low side driver continuity is checked during the continuity test. The driver continuity information will be cleared after the information is transmitted on the next valid SPI command. EXAMPLE—CROSS-COUPLED SQUIB COMMAND SPI SEQUENCE FROM MICROCONTROLLER TX: Squib IC #2 request continuity command ($C2). RX: Previous executed command information. TX: Squib IC #2 request continuity command ($C2). RX: Receive low side driver continuity information for low side drivers which reside on IC #2. TX: Squib IC #1 request another command sequence. RX: Receive low side driver continuity information for low side drivers that reside on IC #1. TX: Squib IC #1 request loop-to-loop short command  ($E0–$E3) RX: Previous executed command information. TX: Squib IC #2 request loop to loop short command for other ICs ($E8). RX: Previous executed command information. TX: Squib IC #2 request loop-to-loop short command for other ICs ($E8). RX: Receive loop-to-loop results from test run on IC #1. TX: Squib IC #1 request another command sequence. RX: Receive loop-to-loop results from test run on IC #1. FIRING A SQUIB The firing of a squib driver requires the FEN_1 and FEN_2 pins to be high and two separate 8-bit writes be made to the shift register. With FEN_1 pin high, squibs 1A and 1B can be armed and fired. With FEN_2 pin high, squibs 2A and 2B can be armed and fired. The first write is to ARM squib drivers in preparation of receiving the fire command. Squib 1A and squib 1B can be armed separately from squib 2A and squib 2B (refer to Table 7) or all squibs can be fired at once (refer to Table 8). All ARM and 5X (Fire) commands will be echoed back on the SPI Data output. TX: Squib IC #1 request squib 1A resistance measurement ($D0). RX: Previous executed command information. 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 21 FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES Table 7. Squib Firing Commands Hex Code Command Description A0 ARM Squib Drivers 1A and 1B A1 ARM Squib Drivers 2A and 2B Byte #1 Byte #2 Squib B High Side Squib B Low Side Squib A High Side A0 ARM Squib Drivers 1A and 1B A1 ARM Squib Drivers 2A and 2B Squib A Low Side Squib 2B A2 Squib 2A Squib 1B Squib A1 ARM Squib Drivers 1A, 1B, 2A, 2B 50 OFF OFF OFF OFF OFF OFF OFF OFF 51 OFF OFF OFF ON OFF OFF OFF ON 52 OFF OFF ON OFF OFF OFF ON OFF 53 OFF OFF ON ON OFF OFF ON ON 54 OFF ON OFF OFF OFF ON OFF OFF 55 OFF ON OFF ON OFF ON OFF ON 56 OFF ON ON OFF OFF ON ON OFF 57 OFF ON ON ON OFF ON ON ON 58 ON OFF OFF OFF ON OFF OFF OFF 59 ON OFF OFF ON ON OFF OFF ON 5A ON OFF ON OFF ON OFF ON OFF 5B ON OFF ON ON ON OFF ON ON 5C ON ON OFF OFF ON ON OFF OFF 5D ON ON OFF ON ON ON OFF ON 5E ON ON ON OFF ON ON ON OFF 5F ON ON ON ON ON ON ON ON The second write is to actually fire the desired driver. The four most significant bits of the second write are used to establish a parity with the four most significant bits of the first write. The four least significant bits are the data bits, and each bit represents a squib driver or squib driver pair. If there is a parity mismatch of the four most significant bits, the data bits will be ignored and the squib drivers will not have their status changed. The 2-byte write sequence must then be started again. During the first write, when the drivers are armed, all diagnostic functions are cleared. Once fired, a driver can only be turned off by one of the following: • Sending a valid 2-byte write sequence through the shift register. • Having the reset pin pulled low. • Having the thermal shutdown limit exceeded (once minimum firing duration requirement has been met; refer to Note (4) in Maximum Ratings). • Having the FEN pin pulled low. Note that the code sequences allow any combination of drivers to be turned on or off. Once fired, the current limit measurement register increments when the squib current is measured and is above the IMEAS threshold during the timer activation. The FEN_1 or FEN_2 pin must be high to enable firing of the drivers. If fire command is active and the FEN (1 or 2) pin is pulled low, the FET drivers will turn off (assuming the latch and hold function is not in effect; refer to paragraph entitled FEN_1 and FEN_2, FEN_1 and FEN_2 (FEN) ($C8 Command)). If fire command is active and the FEN (1 or 2) pin is pulled high, the FET driver will turn on. During the firing of a squib, significant I•R losses may occur, which could cause a voltage shift across a circuit board trace. It is recommended that current paths for discharging the firing supply storage capacitors through the squib be kept as short as possible and isolated from logic and diagnostic grounds. 33797 22 Analog Integrated Circuit Device Data Freescale Semiconductor FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES Table 8. Diagnostic Bit Definitions Hex Code Command Description Diagnostic Data Out (Available on Next Command) Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 0 0 0 0 0 0 0 0 SQB_1A BIT 6 SQB_1A BIT 5 SQB_1A BIT 4 SQB_1A BIT 3 SQB_1A BIT 2 SQB_1A BIT 1 SQB_1A BIT 0 LS SQB_1B BIT 4 SQB_1B BIT 3 SQB_1B BIT 2 SQB_1B BIT 1 SQB_1B BIT 0 LS 00 NOP 70 Squib 1A Current Measurement Time SQB_1A BIT 7 MS 71 Squib 1B Current Measurement Time SQB_1B BIT 7 MS 72 Squib 2A Current Measurement Time SQB_2A BIT 7 MS SQB_2A BIT 6 SQB_2A BIT 5 SQB_2A BIT 4 SQB_2A BIT 3 SQB_2A BIT 2 SQB_2A BIT 1 SQB_2A BIT 0 LS 73 Squib 2B Current Measurement Time SQB_2B BIT 7 MS SQB_2B BIT 6 SQB_2B BIT 5 SQB_2B BIT 4 SQB_2B BIT 3 SQB_2B BIT 2 SQB_2B BIT 1 SQB_2B BIT 0 LS 79 Squib X Current Status 0 0 0 0 7F Thermal Shutdown Status ThermalSD Thermal LSDSTAT _2B Thermal HSDSTAT _2B Thermal LSDSTAT _2A Thermal HSDSTAT _2A Thermal LSDSTAT _1B Thermal HSDSTAT _1B Thermal LSDSTAT _1A Thermal HSDSTAT _1A C0 VDIAG and High Side Safing Sensor Diagnostics RSSLO RSSHI VDIAG _2 VDIAG _2 RSSLO RSSHI VDIAG _1 VDIAG _1 VDHI VDLO VDHI VDLO C1 Squib Short-toGround / Short-toBattery Diagnostics SQB_2B NO_SH_ GND SQB_2B NO_SH_ BATT SQB_2A NO_SH_ GND SQB_2A NO_SH_ BATT SQB_1A NO_SH_ GND SQB_1A NO_SH_ BATT C2 Low Side Driver Continuity Status 0 0 0 0 C3 Harness Short-toGround / Short-toBattery with Squib Open (No Squib Present) SQB_2B OPEN NO_SH_ GND SQB_2B OPEN NO_SH_ BATT SQB_2A OPEN NO_SH_ GND SQB_2A OPEN NO_SH_ BATT Hex Code Command Description C5 C6 SQB_1B BIT SQB_1B BIT 6 5 SQB_2B SQB_2A SQB_1B SQB_1A Current Limit Current Limit Current Limit Current Limit Status Status Status Status SQB_1B NO_SH_ GND SQB_1B NO_SH_ BATT SQB_LO_2B_ SQB_LO_2A SQB_LO_1B SQB_LO_1A CONT CONT CONT CONT SQB_1B OPEN NO_SH_ GND SQB_1B OPEN NO_SH_ BATT SQB_1A OPEN NO_SH_ GND SQB_1A OPEN NO_SH_ BATT Diagnostic Data Out (Available on Next Command) Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 VFIRE_1B and VFIRE_2B Voltage 0 0 0 VFIRE _B X X VHI VLO VDIAG_1 and VDIAG_2 Diagnostics VDIAG_2 V4 VDIAG_1 V4 VDIAG_1 V3 VDIAG_1 V2 VDIAG_1 V1 Tested VDIAG_2 V3 VDIAG_2 V2 VDIAG_2 V1 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 23 FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES Table 8. Diagnostic Bit Definitions (continued) C8 FEN Status, R_LIMIT_X, R_DIAG Status,  IC Type 1 C9 VFIRE_RTN Status (Open Ground) 0 0 0 D0 Squib 1A Resistance SQB_1A RC8 SQB_1A RC7 SQB_1A RC6 D1 Squib 1B Resistance SQB_1B RC8 SQB_1B RC7 D2 Squib 2A Resistance SQB_2A RC8 D3 Squib 2B Resistance E0 R_LIMIT_2 R_LIMIT_1 R_DIAG NO_FAULT NO_FAULT NO_ FAULT FEN 2 Latch Status FEN 1 Latch Status FEN 2 Status FEN 1 Status 0 0 VFIRE_ RTN_2 VF2LOW VFIRE_ RTN_1 VF1LOW SQB_1A RC5 SQB_1A RC4 SQB_1A RC3 SQB_1A RC2 SQB_1A RC1 SQB_1B RC6 SQB_1B RC5 SQB_1B RC4 SQB_1B RC3 SQB_1B RC2 SQB_1B RC1 SQB_2A RC7 SQB_2A RC6 SQB_2A RC5 SQB_2A RC4 SQB_2A RC3 SQB_2A RC2 SQB_2A RC1 SQB_2B RC8 SQB_2B RC7 SQB_2B RC6 SQB_2B RC5 SQB_2B RC4 SQB_2B RC3 SQB_2B RC2 SQB_2B RC1 Shorts Between Squib Loops, Squib 1A 0 0 0 0 SQB_2B SQB_1A SQB_2A SQB_1A SQB_1B SQB_1A SQB_1A E1 Shorts Between Squib Loops, SQUIB 1B 0 0 0 0 SQB_2B SQB_1B SQB_2A SQB_1B SQB_1B SQB_1A SQB_1B E2 Shorts Between Squib Loops, Squib 2A 0 0 0 0 SQB_2B SQB_2A SQB_2A SQB_1B SQB_2A SQB_1A SQB_2A E3 Shorts Between Squib Loops, Squib 2B 0 0 0 0 SQB_2B SQB_2A SQB_2B SQB_1B SQB_2B SQB_1A SQB_2B E8 Shorts Between Squib Loops, for Additional ICs 0 0 0 0 SQB_2B SHORT SQB_2A SHORT SQB_1B SHORT SQB_1A SHORT 0 33797 24 Analog Integrated Circuit Device Data Freescale Semiconductor FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES Table 9. Command Programming and Diagnostic Bit Definitions Hex Code 3X 80 XX 81 Command Description Command Programming Input and Diagnostic Data Out (Available on Next Command) (21) Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Current Measurement Register Reset Command for Squib X Current 1 = ON 0 0 1 1 SQB_2B Data / Timer Reset SQB_2A SQB_1B SQB_1A Data / Timer Data / Timer Data / Timer Reset Reset Reset DATA OUT Squib X Current Register Reset Status 0 0 1 1 SQB_2B Data / Timer Reset SQB_2A SQB_1B SQB_1A Data / Timer Data / Timer Data / Timer Reset Reset Reset Unlock for FEN 1 Counter Registers Programming. 1 0 0 0 0 0 0 0 Response DATA Output: Command Echoed 1 0 0 0 0 0 0 0 Programming Command for FEN 1 Counter 1 = ON FEN1 CNT BIT 7 MSB FEN1 CNT BIT 6 FEN1 CNT BIT 5 FEN1 CNT BIT 4 FEN1 CNT BIT 3 FEN1 CNT BIT 2 FEN1 CNT BIT 1 FEN1 CNT BIT 0 LSB Response DATA OUT FEN 1 Counter Programming Status FEN1 CNT BIT 7 MSB FEN1 CNT BIT 6 FEN1 CNT BIT 5 FEN1 CNT BIT 4 FEN1 CNT BIT 3 FEN1 CNT BIT 2 FEN1 CNT BIT 1 FEN1 CNT BIT 0 LSB Unlock for FEN 2 Counter Registers Programming 1 0 0 0 0 0 0 1 Response DATA Output: Command Echoed 1 0 0 0 0 0 0 1 Notes 21 The second byte for command programming will be treated as a NOP if any FET is firing. The programming commands have to be sequential or they will be treated as a NOP. 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 25 FUNCTIONAL DEVICE OPERATION OPERATIONAL MODES Table 9. Command Programming and Diagnostic Bit Definitions (continued) Hex Code XX Command Description Command Programming Input and Diagnostic Data Out (Available on Next Command) (22) Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 FEN2 CNT BIT 7 MS FEN2 CNT BIT 6 FEN2 CNT BIT 5 FEN2 CNT BIT 4 FEN2 CNT BIT 3 FEN2 CNT BIT 2 FEN2 CNT BIT 1 FEN2 CNT BIT 0 LS FEN2 CNT BIT 7 MS FEN2 CNT BIT 6 FEN2 CNT BIT 5 FEN2 CNT BIT 4 FEN2 CNT BIT 3 FEN2 CNT BIT 2 FEN2 CNT BIT 1 FEN2 CNT BIT 0 LS Unlock to Test High Squib Drivers 1A, 1B, 2A, 2B 1 0 0 0 0 0 1 0 Response DATA Output: Command Echoed 1 0 0 0 0 0 1 0 High Side Driver Transistor Test Command 0 0 0 1 SQB_ 2B High Side Driver “ON” Response DATA OUT High Side Driver Transistor Status VTRANTST1 0 0 0 0 Unlock to Test Low Squib Drivers 1A, 1B, 2A, and 2B 1 0 0 0 0 0 1 1 Response Data Output: Command Echoed 1 0 0 0 0 0 1 1 Low Side Driver Transistor Test Command 0 0 1 0 Response DATA OUT Low Side Driver Transistor Status VTRANTST2 0 0 0 0 Programming Command for FEN 2 Counter 1 = ON Response DATA OUT FEN 2 Counter Programming Status 82 1X 83 2X SQB_2B SQB_ 2A SQB_1B SQB_1A High Side High Side High Side Driver “ON” Driver “ON” Driver “ON” SQB_2A SQB_1B SQB_1A HSDSTAT_2B HSDSTAT_2A HSDSTAT_1B HSDSTAT_1A SQB_ 2B Low SQB_2A SQB_1B SQB_1A Side Driver Low Side Low Side Low Side “ON” Driver “ON” Driver “ON” Driver “ON” SQB_2B SQB_2A SQB_1B SQB_1A LSDSTAT_ 2B LSDSTAT_ 2A LSDSTAT_1B LSDSTAT_1A Notes 22 The second byte for command programming will be treated as a NOP if any FET is firing. The programming commands have to be sequential or they will be treated as a NOP. 33797 26 Analog Integrated Circuit Device Data Freescale Semiconductor FUNCTIONAL DEVICE OPERATION PROTECTION AND DIAGNOSIS FEATURES Table 9. Command Programming and Diagnostic Bit Definitions (continued) Hex Code Command Description Command Programming Input and Diagnostic Data Out (Available on Next Command) (23) Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 90 Reserved for Freescale Read NVM Low X X X X X X X X 91 Reserved for Freescale Read NVM High X X X X X X X X 92 Reserved for Freescale NVM Enable X X X X X X X X 93 Reserved for Freescale Test Mode Enable X X X X X X X X 96 SPI Integrity Check 1 0 0 1 0 1 1 0 Response DATA OUT: $69 Echo to Diagnose the SPI Integrity 0 1 1 0 1 0 0 1 Notes 23 The second byte for command programming will be treated as a NOP if any FET is firing. The programming commands have to be sequential or they will be treated as a NOP. PROTECTION AND DIAGNOSIS FEATURES The diagnostic circuit’s internal references are provided by a bandgap voltage reference, and by scaled currents determined by the resistor value of R_DIAG and the value of the bandgap voltage. Refer to Table 8, and Table 9, as necessary throughout this section. R_DIAG and R_LIMIT_X RESISTOR DIAGNOSTICS ($C8 COMMAND) This function monitors reference currents derived by the R_LIMIT_1, R_LIMIT_2, and R_DIAG resistors. An open pin or short to ground will cause the comparator to give an “out of range resistor value” indication. A short to VDD will have the same effect as an open pin and will cause an “out of range resistor value” indication. R_LIMIT_X and R_DIAG DATA RESULTS If R_LIMIT_X is open, shorted to ground, or shorted to VDD, the bit R_LIMIT_NO_FAULT will be set to “0”. Standard operation will have this bit set to “1”. If R_DIAG is open, shorted to ground, or shorted to VDD, the bit R_DIAG_NO_FAULT will be set to “0”. Standard operation will have this bit set to “1”. The FEN 1 and FEN 2 status bits are a reflection of the FEN_1 and FEN_2 pins. HIGH SIDE SAFING SENSOR DIAGNOSTICS ($C0 COMMAND) This function monitors the VFIRE_XX pin connection to the VDIAG_X pin. The high side safing function is attached to the VFIRE _1A and VFIRE_2A pins. The high side safing function is not available on the VFIRE _1B and VFIRE_2B pins. When enabled, this diagnostic circuit will typically draw less than 500 µA from the VFIRE supply voltage source. Internal window comparators will monitor the voltage difference between the VDIAG_X pin and the VFIRE_XX pin, and will provide two bits of data to indicate if the pin voltage is either above (open) or below (shorted) the threshold levels. When using a high side safing sensor, typical 5.1 k reference resistor must be placed across the sensor to provide a current path for the diagnostic circuit. As long as there is a current path and the safing sensor switch is open, the resulting differential voltage will fall between the comparator thresholds so neither an open fault nor a shorted fault condition will be indicated. A closed safing sensor will be 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 27 FUNCTIONAL DEVICE OPERATION PROTECTION AND DIAGNOSIS FEATURES indicated as a short, and a loss of the connection between the VDIAG_X pin and the VFIRE_XX pin will be indicated as an open. Any external capacitance on the VFIRE_XX pin will affect the time needed to settle to an accurate value. compared to four thresholds and will provide four bits of data to indicate if the pin voltage is above, below, or between the predetermined threshold levels. There is one diagnostic circuit for each VDIAG_X pin. HIGH SIDE SAFING SENSOR DIAGNOSTIC DATA RESULTS VDIAG_X VOLTAGE DIAGNOSTIC DATA RESULTS If the VDIAG_X voltage is above the threshold limit, the If the VFIRE_XX pin is shorted to the VDIAG_X pin, the RSSLO bit will be set to “0” and the RSSHI bit will be set to “0”. If the VFIRE_XX pin has no connection to the VDIAG_X pin, the RSSLO bit will be set to “1” and the RSSHI bit will be set to “1”. Standard operation with a safing sensor resistor will have the RSSHI bit set to “0” and the RSSLO bit set to “1”. VDIAG_X VX bit will be set to “1”. If the VDIAG_X voltage is below the threshold limit, the VDIAG_X VX bit will be set to “0”. FIRING SUPPLY VOLTAGE (VDIAG_X) DIAGNOSTICS ($C0 COMMAND) This function monitors the voltage on the VDIAG_X pin. The supply voltage is compared to two thresholds (nominal and minimum) and will provide two bits of data to indicate if the pin voltage is above, below, or in between the predetermined threshold levels. There is one diagnostic circuit for each VDIAG_X pin. VDIAG_X SUPPLY VOLTAGE DIAGNOSTIC DATA RESULTS If the VDIAG_X voltage is above the high limit, bits VDHI and VDLO will both be set to “1”. If the VDIAG_X voltage is between the high limit and the low limit, bit VDHI will be set to “0” and VDLO will be set to “1”. If the VDIAG_X voltage is below the low limit, bits VDHI and VDLO will both be set to “0”. FIRING SUPPLY VOLTAGE (VFIRE_XX) DIAGNOSTICS ($C5 COMMAND) This function monitors the voltage on the VFIRE_XX pin. The supply voltage is compared to two thresholds (nominal and minimum) and will provide two bits of data to indicate if the pin voltage is above, below, or in between the predetermined threshold levels. There is one diagnostic circuit for each VFIRE_XX pin. VFIRE_XX SUPPLY VOLTAGE DIAGNOSTIC DATA RESULTS If the VFIRE_XX voltage is above the high limit, bits VFHI and VFLO will both be set to “1”. If the VFIRE_XX voltage is between the high limit and the low limit, bit VFHI will be set to “0” and VFLO will be set to “1”. If the VFIRE_XX voltage is below the low limit, bits VFHI and VFLO will both be set to “0”. FIRING SUPPLY VOLTAGE DIAGNOSTICS, VDIAG_X V1, V2, V3, V4 ($C6 COMMAND) The VDIAG_X V1, V2, V3, V4 function monitors voltage on the VDIAG pins. The voltage being measured is then VFIRE_RTN DIAGNOSTICS ($C9 COMMAND) This function monitors the resistance on the VFIRE_RTN pin for open pin connections. The VFIRE_RTN voltage is compared to a threshold to determine if the VFIRE_RTN pin connection between the pin and the printed circuit board is shorted or open. VFIRE_RTN DIAGNOSTIC DATA RESULTS If the VFIRE_RTN pin is above the threshold limit (open), the VFIRE_RTN X VFXLOW will be set to “1”. If the VFIRE_RTN pin is below the threshold limit (shorted), the VFIRE_RTN X VFXLOW will be set to “0”. VFIRE return tests are disabled during firing. DESIGN NOTES For all standard or cross-coupled squib IC configurations, the SQB_LO_XX pin must be tied to a SENSE_XX pin for either squib IC #1 or squib IC #2 (see Figure 6 and Figure 8). An active 600 A current sink is located in the SENSE_XX pin. The sink current is used to pull the charge off the external EMC / filter caps after a diagnostic measurement has been made. SQUIB SHORT-TO-BATTERY / GROUND DIAGNOSTICS ($C1 COMMAND) This function monitors the voltage on the SENSE_XX pins. The voltage is compared to two thresholds (minimum and maximum) and will provide two bits of data to indicate if the pin voltage is above, below, or in between the predetermined threshold levels. When enabled, a 2.7 mA current source located in the SQB_HI_XX pin is activated, sourcing current from the SQB_HI_XX to the SENSE_XX pin. When resistive measurement legs to comparators located in the SENSE_XX pin are activated, a fault on either side of the squib can be easily detected. An external current path that causes the SQB_LO_XX, SQB_HI_XX, or SENSE_XX pin to be pulled below the minimum threshold, will be indicated as a “Short to Ground”. If the SQB_LO_XX, SQB_HI_XX, or SENSE_XX pin has an external current path that causes the pin to be pulled above the maximum threshold, a “Short to Battery” will be indicated. 33797 28 Analog Integrated Circuit Device Data Freescale Semiconductor FUNCTIONAL DEVICE OPERATION PROTECTION AND DIAGNOSIS FEATURES SQUIB SHORT-TO-BATTERY/GROUND DIAGNOSTIC DATA RESULTS If SQB_LO_XX, SQB_HI_XX, or SENSE_XX pin is shorted to battery, the bit NO_SH_BATT will be set to “0”. If a SQB_LO_XX, SQB_HI_XX, or SENSE_XX pin is shorted to ground, the bit NO_SH_GND will be set to “0”. During standard operation, both NO_SH_BATT and NO_SH_GND will be set to “1”. Note This diagnostic circuit uses an internal 2.7 mA current source connected to the SQB_HI_XX pin as a bias. If the SQB_LO_XX and SQB_HI_XX pins have any capacitance (due to discrete capacitors or parasitic loading), the diagnostic condition will require a settling time based on the RC time constant. SQUIB HARNESS SHORT-TO-BATTERY / GROUND DIAGNOSTICS WITH AN OPEN SQUIB ($C3 COMMAND) This diagnostic function is to be used with no squib present (open squib condition) in the wiring harness. For an open squib condition, the function must monitor the voltage on the SQB_HI_XX and SQB_LO_XX pins for “Short to Ground” and “Short to Battery” conditions. This function monitors the voltage on the SENSE_XX pins. The voltage is compared to two thresholds (minimum and maximum) and will provide two bits of data to indicate if the pin voltage is above, below, or in between the predetermined threshold levels. When enabled, a pair of opposing N-channel CMOS transistors are activated, creating roughly a 500 resistance between the SQB_HI_XX and SQB_LO_XX pins together. A 2.7 mA current source located in the SQB_HI_XX pin is activated, sourcing current from the SQB_HI_XX to the SQB_LO_XX pin to the SENSE_XX pin. When resistive measurement legs to comparators located in the SENSE_XX pin are activated, a short to BAT / GND fault can easily be detected. An external current path that causes the SQB_LO_XX, SQB_HI_XX, or SENSE_XX pin to be pulled below the minimum threshold, will be indicated as a “Shortto-Ground”. If the SQB_LO_XX, SQB_HI_XX, or SENSE_XX pin has an external current path that causes the pin to be pulled above the maximum threshold, a “Short-to-Battery” will be indicated. SQUIB SHORT-TO-BATTERY/GROUND DIAGNOSTIC DATA RESULTS If SQB_LO_XX, SQB_HI_XX, or SENSE_XX pin is shorted to battery, the bit OPEN NO_SH_BATT will be set to “0”. If a SQB_LO_XX, SQB_HI_XX, or SENSE_XX pin is shorted to Ground, the bit OPEN NO_SH_GND will be set to “0”. During standard operation, both OPEN NO_SH_BATT and OPEN NO_SH_GND will be set to “1”. Notes 1. This diagnostic circuit uses an internal 2.7 mA current source connected to the SQB_HI_XX pin as a bias. If the SQB_LO_XX and SQB_HI_XX pins have any capacitance (due to discrete capacitors or parasitic loading) the diagnostic condition will require a settling time based on the RC time constant. 2. With an OPEN NO_SH_GND or OPEN_NO_SH_BATT indicated, the SQB_HI_XX or SQB_LO_XX line contains the fault condition. The standard squib shortto-battery / ground diagnostics ($C1) can be executed to determine if the fault condition is on the SQB_HI_XX pin or the SQB_LO_XX pin. CONTINUITY TEST for the LOW SIDE DRIVER SQB_LO_XX CONNECTION ($C2 COMMAND) (LOW SIDE DRIVER CONTINUITY STATUS) Low side driver continuity is checked during the continuity test diagnostics. This function is used to check continuity at the SQB_LO_XX pin connection. When enabled, a 2.0 mA current source located in the SQB_HI_XX pin is activated sourcing current from the SQB_HI_XX to the SQB_LO_XX pin. For a standard connection, the SQUIB_LO_XX_CON bit will be set to “1”. With an open circuit connection, the SQUIB_LO_XX bit will be set to “0”. The driver continuity information will be cleared after the information is transmitted on the next valid SPI command. SQUIB RESISTANCE DIAGNOSTICS ($D0–$D3 COMMAND) This function monitors squib resistance. When enabled, a diagnostic current derived from R_DIAG is passed through the selected squib. The resulting voltage across the squib is amplified and passed to an 8-bit voltage level detector. The eight bits of data will indicate if the selected squib has a resistance value above or below predetermined thresholds. The value of R_DIAG can be varied to allow the detection range to be altered. Increasing the value of R_DIAG will reduce the diagnostic current; thus, a higher squib resistance will be needed to reach the same RTH points. In the case that R_DIAG is a short-to-ground, the diagnostic current through the squib resistance will typically be less than 50 mA. SQUIB RESISTANCE DIAGNOSTIC DATA RESULTS A comparator result bit set to “1” indicates that the input voltage is above the threshold resistance for that bit. Thus an open squib would cause all bits to be set to “1”; likewise, a shorted squib will cause all bits to be set to “0”. Squib resistance tests are disabled during firing. SQUIB DIAGNOSTICS SHORTS BETWEEN SQUIB LINES (FIRING LOOPS) ($EX COMMAND) This function monitors conditions that have shorts between squib lines (firing loops). When enabled, a 2.7 mA current source located in the SQB_HI_XX pin is activated sourcing current from the selected SQB_HI_XX to the SENSE_XX pin. The resulting voltage is checked on all other squib lines to 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 29 FUNCTIONAL DEVICE OPERATION PROTECTION AND DIAGNOSIS FEATURES determine if the squib lines are shorted. In applications using more than one squib driver IC, a separate command can also be issued to check all squibs for shorted squib lines. SQUIB DIAGNOSTICS SHORTS BETWEEN SQUIB LINES DIAGNOSTIC DATA RESULTS (SHORTS BETWEEN FIRING LOOPS) A comparator result bit set to “1” for SQUIB_XX indicates standard test current detected in squib line under test. A comparator result bit set to “0” for SQUIB_XX indicates faulty diagnostic current detected in squib line under test. A comparator result bit set to “1” for SQUIB_XX_SSQB_ YY indicates that the squib line is shorted to the squib under test. A comparator result bit set to “0” for SQUIB_XX_SSQB_YY indicates no shorted squib line detected (standard conditions). If more than two squibs are shorted together, the response will consist of all “0”s. RESET (RST) The RESET pin has an internal current pull-down of typically 40 A. While this pin is low, the internal functions of the squib driver IC are disabled and all data in the serial interface shift registers is cleared. This includes all FEN 1 and 2 counter programming, squib driver activation, and squib driver FET tests. With a minimum system VDD  4.1 V, the system reset bar threshold will be set to “0”. FEN_1 and FEN_2 (FEN) ($C8 COMMAND) FEN_1 and FEN_2 have an internal current pull-down of typically 40 A. While the FEN pin is low, firing of the FET drivers is disabled. All internal diagnostic functions and results will be available through the serial interface. The FEN pin must be pulled high to enable firing of the FET drivers. Also, the pin state can be used to turn the FET driver “ON” and “OFF” after the arm and fire command has been issued. (That is, once the FET drivers are turned on, pulling FEN_1 or FEN_2 low can turn the drivers off if the latch and hold function is not active, and pulling FEN_1 or FEN_2 high will activate the drivers if the fire command is still active). Status of FEN 1 and FEN 2 is contained in the C8 diagnostic byte, as shown in Table 8). The FEN_1 and FEN_2 function should be capable of latching and holding the enable function for electronic safing function input. This function is required for dual-stage air bag applications. FEN_1 or FEN_2 will be considered active when either pin is active (“1”) for more than 12 ms. Tolerance range for the filter to be used will be 12 to 16 s. When FEN_1 or FEN_2 input is active high, the FEN_1 or FEN_2 function will be active high. When the FEN_1 or FEN_2 input state transitions from high to low, a programmable latching function will hold the FEN function active until the timeout of the FEN timer. The programmable latch and hold function will be capable of delays from 1.0 ms to 255 ms, in 1.0 ms increments. The timer is reset to programmed time when FEN_1 or FEN_2 pin transitions from “0” to “1”. The programmable counter delay will be set through an SPI command during module power-up / proveout. The default for the counter will be 0 ms. The bits FEN 1 and FEN 2 STATUS are a reflection of their respective pins. The counter will be reset to 0-Sec time during a reset condition. Notes 1. Status information will be required to read counterprogrammed value. 2. Precautions need to be taken in the design to prevent the latching function from becoming a glitch catching function. FEN 1 and FEN 2 COUNTER PROGRAMMING ($80 and $81 COMMAND) The FEN 1 and FEN 2 counters require two separate 8-bit writes be made to the shift register. The first write is to unlock ($80 or $81) and reset the FEN counter registers in preparation of receiving a command. The second byte contains the programming information to set the required counter delay time (0 ms to 255 ms with 1.0 ms interval). Squib IC Power-Up default and $80 or $81 followed by $00 command will set the counter to 0 ms timer delay (refer to Table 9, page 25.) The FEN 1 and FEN 2 Counter programming status bits are a reflection of the counters programming. The programming status information can be compared to the data sent to ensure the squib driver was programmed properly. Counter programming status will be shifted from the shift register during the next read / write operation (Table 9). All unlock commands will be echoed back on the SPI Data output. FET DRIVER CURRENT LIMIT A single resistor is used to set the current limit protection of the high side drivers of both squib channels. The low side current limit is never less than the high side current limit. Table 10. RR_LIMIT_X Current Limit RR_LIMIT_X VVFIRE = 7.0 V VVFIRE = 35 V 4.32 k 0.92 A 0.92 A 10 k 1.37 A 1.37 A 45.3 k 2.0 A 2.0 A Example of current limit conditions: RR_LIMIT_X = 10 k, IHS = A ± A The high side driver controls the current through the squib. The current limit for the low side driver is only to protect the low side driver stage from excessive current in the event of a short to battery. With RR_LIMIT_X conditions < 4.32 k or shorted to ground, the current limit will default to the RR_LIMIT_X = 10 k current limit, not to exceed. With RR_LIMIT_X resistance value > 60 k 33797 30 Analog Integrated Circuit Device Data Freescale Semiconductor FUNCTIONAL DEVICE OPERATION PROTECTION AND DIAGNOSIS FEATURES or open, the current limit will default to the RR_LIMIT_X = 10 k maximum current limit. FET DRIVER CURRENT LIMIT MEASUREMENT ($7X COMMAND) This function measures the firing current in each squib line and records the “ON” time in which the IMEAS is above the threshold for each squib. (Refer to Dynamic Electrical Characteristics table, Dynamic Electrical Characteristics.) The timing registers can be reset via SPI command so additional current measurements can be made. An 8-bit message will be used to determine 255 time steps. The driver current limit measurement is activated when each individual high side driver is activated. Each time the squib current is measured above the IMEAS threshold during the timer activation, a status bit will be set to “1”. If the current measured is not above the IMEAS threshold during the timer activation, the timing data log bit will not increment. Each squib timing register can be reset via SPI command so additional current measurements can be made. Initial squib IC power-up will reset the timing registers (i.e., “Power-ON Reset”). When reset, the current limit measurement register byte will be set to $00. Command $79 will indicate the status of the current limit measurement comparator. The current limit measurement from the test is captured and loaded into the register on the next valid SPI command. When the firing current is above IMEAS, the current limit is activated and the status bit will be set to “1”. If the firing current is below IMEAS, the current limit status bit will be set to “0”. FET DRIVER CURRENT LIMIT MEASUREMENT RESET COMMAND ($3X COMMAND) The current limit status registers can be individually reset with the command set found in Table 9. When the register bit is set to “1” for squib X, the current measurement register will be reset to $00. SQUIB DRIVER THERMAL SHUTDOWN ($7F COMMAND) With a nominal squib load, the FET squib driver will not enter thermal shutdown until the driver has been active for a minimum of 2.09 ms. The individual squib driver thermal shutdown will not affect other squib drivers firing “ON” times. With a shorted squib load, the FET squib driver will not enter thermal shutdown until the driver has been active for a minimum of 2.090 ms. For the shorted squib load, the associated FET squib driver may enter thermal shutdown with an “ON” time of 2.09 ms  tON  2.82 ms. When the thermal shutdown limit is exceeded, the thermal status will be set to “1”. The thermal shutdown status ($7F) diagnostics latch the thermal bit status when executed. The Squib Driver Thermal shutdown status latch will be cleared after the information is transmitted on the next valid SPI command (i.e., TX: NOP or next $7F, latch cleared on rising edge of chip select). The FET squib driver can be activated through the arm / fire command when the TEMPRENABLE (MIN) is reached (thermal shutdown status “0”). VTRANTSTX, HIGH AND LOW SIDE SQUIB DRIVER FET TEST and STATUS ($82 TO $83 COMMAND) This function checks the squib driver FET transistor status. The high and low side squib driver FET test requires FEN_1 and FEN_2 pins to be low and two separate 8-bit write commands to be made to the shift register. With the FEN_1 and FEN_2 pins status LOW, the first write is to unlock in preparation of receiving the diagnostic command for testing the high and low side squib drivers. The unlock command ($82 and $83) is an “AND” function with the FEN_1 and FEN_2 BAR. All transistor test unlock commands ($82 and $83) will be echoed back on the SPI Data output. The high or low side squib driver FET test will be aborted if firing from any FET is enabled. During the first write (unlock command), all diagnostic functions are cleared. After the second write is completed, all other diagnostic functions are made available again. Squib 1A, squib 1B, squib 2A, and squib 2B high side squib drivers will be activated and diagnosed by the $82 followed by $1X diagnostic command (refer to Table 9). A load from the SQB_HI_XX pin to the SENSE_XX pin is required for the high side squib driver to be tested. Squib 1A, squib 1B, squib 2A, and squib 2B low side squib drivers will be activated and diagnosed by the $83 followed by $2X diagnostic command (Table 9). When enabled the high or low side FET driver will be enabled and current limited to a nominal current limit of 10 mA. The high and low side driver test time is not automated and is controlled through SPI. When either a $82 or a $83 command is issued, the previous transistor test will stop to prevent coinciding high and low side FET drive transistors from turning “ON”. This prevents high and low side drivers from being activated simultaneously. Note The high or low side squib driver test is capable of checking a code sequence, allowing any combination of high or low side drivers to be tested. The diagnostic squib driver bit (HSDSTAT_X or LSDSTAT_X) will be set to “1” if the squib driver did not activate (turn “ON”) during the diagnostic test. The diagnostic squib driver bit (HSDSTAT_X or LSDSTAT_X) will be set to “0” if the squib driver did activate (turn “ON”) during the diagnostic test. Diagnostic data will be shifted from the shift register during the next read/write operation. The diagnostic squib driver register will be set / cleared to “0” when the unlock command is loaded ($82 or $83 loaded with rising edge of CS). A diagnostic bit set to “0” indicates standard squib driver transistor operation. 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 31 PACKAGING PACKAGE DIMENSIONS PACKAGING PACKAGE DIMENSIONS Important For the most current revision of the package, visit www.freescale.com and do a keyword search on the 98A drawing number below. EW SUFFIX (PB-FREE) 32-PIN 98ARH99137A REVISION B 33797 32 Analog Integrated Circuit Device Data Freescale Semiconductor PACKAGING PACKAGE DIMENSIONS . EW SUFFIX (PB-FREE) 32-PIN 98ARH99137A REVISION B 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 33 PACKAGING PACKAGE DIMENSIONS EW SUFFIX (PB-FREE) 32-PIN 98ARH99137A REVISION B 33797 34 Analog Integrated Circuit Device Data Freescale Semiconductor REVISION HISTORY REVISION HISTORY Revision 3.0 4.0 Date 11/2006 Description of Changes • • • • Updated to the current Freescale format and style Implemented Revision History page Added MCZ33797EK/R2 Removed Peak Package Reflow Temperature During Reflow (solder reflow) parameter from Maximum Ratings on page 6. Added note with instructions from www.freescale.com. • In Static Electrical Table changed Input Voltage minimum from 4.57 to 4.75 on page 7, for symbol ITHSQB CON, corrected Unit of Measurement from mA to , and for VDIAG Supply Diagnostics, changed Command from $C5 to $C6 onpage 10 Changed High Side Safing Sensor Diagnostic Data Results on page 28. Updated Outline Drawing to Revision B. 6/2007 • • 5.0 11/2011 6.0 2/2014 • • Removed MCZ33797EK/R2 from the ordering information and added MC33797BPEW/R2 Updated the Static and Dynamic Electrical Characteristics Table (min and max ratings) for MC33797BPEW. • No technical changes. Revised back page. Updated document properties. Added SMARTMOS sentence to last paragraph. 33797 Analog Integrated Circuit Device Data Freescale Semiconductor 35 How to Reach Us: Information in this document is provided solely to enable system and software implementers to use Freescale products. Home Page: freescale.com There are no express or implied copyright licenses granted hereunder to design or fabricate any integrated circuits based Web Support: freescale.com/support Freescale reserves the right to make changes without further notice to any products herein. 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Freescale and the Freescale logo are trademarks of Freescale Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off.SMARTMOS is a trademark of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © 2014 Freescale Semiconductor, Inc. Document Number: MC33797 Rev 6.0 2/2014