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MC33797 rev 2.0, 07/2005 freescale semiconductor technical data * this document contains certain information on a new product. specifications and information herein are subject to change without notice. ? freescale semiconductor, in c., 2005. all rights reserved. four channel squib driver ic 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 de vice 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-coupl ed state with the high- and low-side squib drivers located on separate squib driver ics. both the high- and low-side output drivers are protect ed against temporary shorts to battery or ground. the current limit threshold is set by an external resistor. features ? 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 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) ? pb-free packaging designated by suffix code ek figure 1. 33797 simplified application diagram squib driver 33797 ordering information device temperature range (t a ) package MC33797ek/r2 -40c to 85c 32 soicw ek suffix (pb-free) 98arh99137a 32-terminal soicw vdiag_2 vfire_1a vdiag_1 fen_1 fen_2 cs vfire_2b vdd vfire_2a sqb_hi sense vfire_rtn sqb_lo r_limit_2 gnd vfire_1b r_limit_1 r_diag mosi clk miso 33797 firing cap firing cap v pwr typical air bag power supply vin vboost1 vboost2 enable enable squib (1a, 1b, 2a, 2b) /4 /4 /4 /2 microprocessor rst 5.0 v
analog integrated circuit device data 2 freescale semiconductor 33797 internal block diagram internal block diagram figure 2. 33797 simplifi ed internal block diagram sqb_hi_1a sense_1a sqb_lo_1a vfire_rtn sqb_lo_1b sense_1b sqb_hi_1b clk gnd r_limit_1 r_limit_2 sqb_hi_2a sense_2a sqb_lo_2a vfire_rtn sqb_lo_2b sense_2b sqb_hi_2b rst r_diag vfire_2b vdiag_2 fen_1 fen_2 vfire_2a vdd vdiag_1 vfire_1b vfire_1a control and diagnostic multiplex driver control driver control driver control driver control mosi cs miso
analog integrated circuit device data freescale semiconductor 3 33797 terminal connections terminal connections figure 3. terminal function description sqb _ lo _ 2a 1 sqb _ hi _ 2a vfire_2a vdiag_2 vfire_rtn vfire_rtn r _ diag vfire_2b sqb _ hi _ 2b fen_2 sense_2b sqb _ lo _ 2b r _ limit _ 2 rst sense_2a cs sqb _ lo _ 1a sqb _ hi _ 1a vfire_1a vdiag_1 gnd miso vdd vfire_1b sqb _ hi _ 1b fen_1 sense_1b sqb _ lo _ 1b r _ limit _ 1 clk sense_1a mosi 8 9 10 11 12 13 14 15 16 3 4 5 6 7 2 32 25 24 23 22 21 20 19 18 17 30 29 28 27 26 31 table 1. terminal function description terminal terminal name terminal function formal name terminal description 1sqb _ lo _ 1a output squib lo 1a drain of the low-side switch that connects to the low terminal of squib_1a 2 sense_1a input squib sense 1a used during st andard applications involving a four-channel squib driver ic or during cros s-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. 5sqb _ hi _ 1a output squib hi 1a drain of the high-side sw itch that connects to the low terminal of squib_1a 6 vfire_1a supply squib firing supply 1a firing supply terminal for squib_1a. 7 vdiag_1 input squib diagnostic 1a and 1a diagnostic terminal for high-side safing sensor for squibs 1a and 1b and the vfire supply voltage. 8 gnd ground device ground device ground terminal 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 terminal for internal logic and diagnostic circuitry. 11 vfire_1b supply squib firing supply 1b firing supply terminal for squib_1b. 12 sqb _ hi _ 1b output squib hi 1b drain of the high-side sw itch that connects to the low terminal of squib_1b 13 fen_1 input fet driver 1a and 1b active high input signal to enab le 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.
analog integrated circuit device data 4 freescale semiconductor 33797 terminal connections 15 sense_1b input squib sense 1b used during st andard applications involving a four-channel squib driver ic and during cros s-coupling applications involving two four-channel squib driver ics (squib driver ic #1 and squib driver ic #2). 16 sqb _ lo _ 1b output squib lo 1b drain of the low-side switch that connects to the low terminal of squib_1b 17 sqb _ lo _ 2b output squib lo 2b drain of the low-side switch that connects to the low terminal of squib_2b 18 sense_2b input squib sense 2b used during st andard applications involving a four-channel squib driver ic and during cros s-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 enab le operation of the squib_2a and squib_2b fet drivers. 21 sqb _ hi _ 2b output squib hi 2b drain of the high-side sw itch that connects to the low terminal of squib_2b. 22 vfire_2b supply squib firing supply 2b firing supply term inal 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 terminal 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 terminal for squib_ 2a 28 sqb _ hi _ 2a output squib hi 2a drain of the high-side sw itch that connects to the low terminal 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 st andard applications involving a four-channel squib driver ic or during cros s-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 terminal of squib_2a table 1. terminal function description (continued) terminal terminal name terminal function formal name terminal description
analog integrated circuit device data freescale semiconductor 5 33797 maximum ratings maximum ratings table 2. maximum ratings (1) all voltages are with respect to ground unless otherwise noted. rating symbol value unit input electrical ratings voltage on vdd v dd 7.0 v voltage on input terminals cs , clk, d1, d0, fen_1, fen_2, resetb, r_diag, r_limit_x v i -0.3 to v dd + 0.3 v voltage on squib terminals sqb_hi_xx, sqb_lo_xx, sense_xx v vfire_xx -0.3 to v vfire + 0.3 v voltage on terminals vdiag_x, vfire_xx vdiag_x -0.3 to 35 v esd voltage human body model (2) machine model (3) v esd1 v esd2 2000 200 v maximum v vfire with pulsed output (4) , (5) r squib = 2.0 ? , t on = 0.8 ms, i squib = 2.24 a r squib = 1.2 ? , t on = 0.8 ms, i squib = 2.24 a r squib = 0.1 ? , t on = 0.60 ms, i squib = 2.24 a v fpulse 35 25 25 v thermal ratings storage temperature t stg 155 c junction temperature ambient continuous (prior to squib deployment) t 5.0 ms (post-squib deployment) t a t jcont t jdpyd 85 100 300 c lead soldering temperature (6) t solder 245 c thermal resistance (junction-to-ambient) r j-a 74 c/w operating ratings (7) low-side fet fire conditions r squib t on i squib v squibhi 2.0 ? 2.6 ms 3.0 a 16 v 1.2 ? 2.6 ms 3.0 a 16 v 0.1 ? 2.6 ms 3.0 a 16 v notes 1. absolute maximum ratings indicate limits beyond which damage to the device may occur. 2. esd1 testing is performed in accordance with the human body model (c zap = 100 pf, r zap = 1500 ? ). 3. esd2 testing is performed in ac cordance with the machine model (c zap = 200 pf, r zap = 0 ? ). 4. with a nominal squib load, the fet squib driver will not ent er thermal shutdown until the driver has been active for a minimu m of 2.1 ms. the individual squib driver therma l shutdown will not affect other squib driver fi ring ?on? times. with a shorted squib load, t he 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 limi t is exceeded, the fet driver will turn off and th e thermal status bit will be set to 1. the fet squib driver can be activated through the arm/fire command when the temp renable (min) is reached (thermal shutdown status ?0?). nominal squib load is 2.15 ? 0.15 ? . shorted squib load is 0.1 ?. 5. three-squib driver with r squib = 0.1 ? conditions. remaining squi b driver conditions: r squib =1.2 ? , t on = 4.0 ms, i squib =2.0a, v vdiag_x =v vfire_xx =35v. 6. lead soldering temperature limit is for 10 seconds maximum durat ion; not designed for immersion soldering. exceeding these lim its may cause malfunction or permanent damage to the device. 7. operating ratings indicate conditions for which the device is intended to be functional. for guaranteed specifications and te st conditions, refer to the static and dynamic electrical characteristics tables on the following pages.
analog integrated circuit device data 6 freescale semiconductor 33797 static electrical characteristics static electrical characteristics table 3. static electr ical characteristics characteristics noted under conditions 4.75 v v dd 5.25 v; 7.0 v v vfire_xx 35 v; v vdiag_x = v vfire_xx ; fen 1 = fen 2 = v dd ; r r_limit_x =10k ? 1%, r r_diag = 10 k ? 1%, -40 c t a +85 c, gnd = 0 unless otherwise noted. typical values noted reflect the approximate parameter means at t a = 25c under nominal conditions unless otherwise noted. characteristic symbol min typ max unit input voltage (vdd) input voltage v dd 4.57 5.0 5.25 v fet drivers leakage current at minimum high side driver breakdown voltage i dhsd ?39 100 a leakage current at minimum low side driver breakdown voltage i dlsd ?65 100 a high-side driver current limit range set via rlimit resistor with low battery condition t on 4.0 ms, r r_limit_x = 10 k ? , 5.0 v v vfire 7.0 v, r squib = 2.0 ? i hs(lbat) 1.09 1.4 2.9 a high-side driver low current limi t range set via rlimit resistor t on 2.6 ms, r r_limit_x = r l =4.32 k ?, 7.0 v v vfire 35 v i hs(loset) 0.81 0.93 1.03 a high-side driver nominal current li mit range set via rlimit resistor t on 2.6 ms, r r_limit_x = r l =10 k ?, 7.0 v v vfire 35 v i hs(nom) 1.21 1.4 1.54 a high-side driver high current limi t range set via rlimit resistor t on 0.8 ms, r r_limit_x = r l =45.3 k ?, 7.0 v v vfire 35 v i hs(hiset) 1.76 2.0 2.24 a low-side drivers current limit 7.0 v = sqlo < 16 v sqlo = 16 v i ls 2.1 2.24 2.47 2.65 3.0 3.14 a high-side driver current limit detect threshold (8) 7.0 v v vfire 35 v i meas i hs x0.85 ? i hs x1.0 a driver on resistance (per fet) v vfire = 5.0 v, i load = 0.5 a r ds(on) ??1.0 ? vdd operating current standby (diagnostics off, spi ?off?) no fire?worst case diagnostics ($83/$2f command active) firing (with all fet drivers ?on?) i dd ? ? ? 2.0 15 4.3 5.0 17.5 6.0 ma vfire quiescent current (9) with diagnostics off i rre 22 34 55 a vdiag current during squib diagnostics with squib resistance diagnostics active i rre 32 37 43 ma vfire operating current during firing excluding firing current, i hs = 2.0 a i rre ?1.810 ma vdiag operating current during firing per v diag terminal, excluding firing current, i hs = 2.0 a i rre ? 140 200 a notes 8. guaranteed by design 9. vfire quiescent current includes any leakage current through squib.
analog integrated circuit device data freescale semiconductor 7 33797 static electrical characteristics vfire1a / vfire2a current during high side safing sensor diagnostics (command $co) per vfirexa terminal, with high side safing sensor diagnostic active i rre 260 350 400 a vfire1b / vfire2b current during high side safing sensor diagnostics (command $co) per vfirexb terminal, with high side safing sensor diagnostic active i rre 22 32 55 a vfire1b / vfire2b current during vfire diagnostics (command $c5) either vfire!b or vfire2b diagnostic active i rre 0.3 2.0 3.8 ma vfire quiescent current - total all vfire terminals measured t ogether, with diagnostics off i qvfiretotal 90 135 180 a maximum allowable external capacitance to ground (10) per squib terminal sqb_lo and sqb_hi cs max ? ? 0.12 f maximum allowable external resistance to ground during firing (10) vfire_rtn terminal to ground rs max ? ? 0.15 ? individual fet driver thermal shutdown (10) , (11) t sd 160 ? 190 c fet driver thermal shutdown re-enable threshold after drive cool-down (10) , (11) t ren 90 ? 110 c fet drivers high- and low-side driver transistor status/diagnostics ($82, $83 commands) voltage transistor test threshold for high-side driver transistor v trantst1 5.5 6.0 6.5 v high-side driver current limit du ring high-side driver transistor diagnostics 15 v v vfire_xx 35 v i trantst1 2.0 10 50 ma voltage transistor test threshol d for low-side driver transistor v trantst2 1.0 1.4 2.0 v low-side driver current limit during low-side driver transistor diagnostics 15 v v vfire_xx 35 v i trantst2 2.0 10 50 ma fen input terminal (fen_1 and fen_2) internal current pull-down i fen -25 -40 -50 a logic low level v fen(lo) 0.0 2.5 0.35 x v dd v fire enable terminal logic high level v fen(hi) 0.65 x v dd 2.5 1.0 x v dd v notes 10. guaranteed by design. 11. with a nominal squib load, the fet squib driver will not enter thermal shutdown unt il the driver has been active for a minim um of 2.1 ms. the individual squib driver therma l 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 limi t is exceeded, the fet driver will turn off and the thermal status bit will be set to 1. the fet squi b driver can be activated throu gh the arm/fire command when the temp renable (min) is reached (thermal shutdown status ?0?). nominal squib load: 2.15 ? 0.15 ? . shorted squib load: 0.1 ?. table 3. static electrical characteristics (continued) characteristics noted under conditions 4.75 v v dd 5.25 v; 7.0 v v vfire_xx 35 v; v vdiag_x = v vfire_xx ; fen 1 = fen 2 = v dd ; r r_limit_x =10k ? 1%, r r_diag = 10 k ? 1%, -40 c t a +85 c, gnd = 0 unless otherwise noted. typical values noted reflect the approximate parameter means at t a = 25c under nominal conditions unless otherwise noted. characteristic symbol min typ max unit
analog integrated circuit device data 8 freescale semiconductor 33797 static electrical characteristics rst input terminal (active low) (12) system reset threshold v ddrst ??4.1v internal current pull-down i rst -6 -10 -15 a rst logic low level v rst (lo) 0.0 2.5 0.35 x v dd v rst logic high level v rst (hi) 0.65 x v dd 2.5 1.0 x v dd v squib diagnostics ($d0?$d3 commands) (13) diagnostic current through squib (14) i diag 30 34 40.5 ma resistance threshold 1 (14) r th1 1.2 1.4 1.6 ? resistance threshold 2 (14) r th2 1.6 1.8 2.1 ? resistance threshold 3 (14) r th3 2.1 2.4 2.6 ? resistance threshold 4 (14) r th4 2.6 2.9 3.2 ? resistance threshold 5 (14) r th5 3.3 3.7 4.4 ? resistance threshold 6 (14) r th6 4.6 5.4 6.0 ? resistance threshold 7 (14) r th7 5.7 6.5 7.1 ? resistance threshold 8 (14) r th8 6.7 7.8 8.5 ? squib short-to-battery/ground diag nostics and squib harness short-to -battery/ground diagnostics with an open squib ($c1, $c3 commands) voltage threshold for sqb _ lo and sqb_hi shorted to v pwr 7.0 v v vdiag_x 35 v v thsb 5.7 6.0 6.4 v voltage threshold for sqb _ lo and sqb_hi shorted to ground 7.0 v v vdiag_x 35 v v thsg 1.3 1.4 1.6 v current sink shorts measurements i_sqb_lo_xx (15) 1.0 v sense_xx 16 v, typical = 800 a i sinkshrts -500 -800 -900 a current source shorts measurements i_sqb_hi_xx (15) 1.0 v sense_xx 16 v, 7.0 v v vdiag_x 35 v i sourshrts 1.7 3.5 3.7 ma voltage threshold for sqb_lo or sqb_hi shorted to v pwr with an open squib using $c3 command r squib = open v thsb_so 5.75 ? 6.75 v notes 12. reset bar range of operation: the minimum system reset ba r threshold/active will be set to ?0? for a value of v dd 4.1 v. 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%. de sign 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 4 , page 11 . 14. r r_diag = 10 k ? 1.0% 15. xx = 1a, 1b, 2a, or 2b. table 3. static electrical characteristics (continued) characteristics noted under conditions 4.75 v v dd 5.25 v; 7.0 v v vfire_xx 35 v; v vdiag_x = v vfire_xx ; fen 1 = fen 2 = v dd ; r r_limit_x =10k ? 1%, r r_diag = 10 k ? 1%, -40 c t a +85 c, gnd = 0 unless otherwise noted. typical values noted reflect the approximate parameter means at t a = 25c under nominal conditions unless otherwise noted. characteristic symbol min typ max unit
analog integrated circuit device data freescale semiconductor 9 33797 static electrical characteristics voltage threshold for sqb_lo or sqb_hi shorted to ground with an open squib using $c3 command r squib = open v thsg_so 1.3 1.8 2.0 v diagnostics for squib continuity betwee n sense_xx and sqb_lo_xx ($c2 command) current threshold for squib_lo_1a, 1b , 2a, and 2b continuity check for standard and cross-coupled conditions ($c2) squib_lo_xxcont (16) 7.0 v v vdiag_x 35 v i thsqb con 150 ? 350 ma diagnostics for squib short between firing loops ($e0?$e3, $e8 commands) voltage threshold for standard squib connection 7.0 v v vdiag_x 35 v v thsqbnom 1.0 1.4 2.0 v voltage threshold for squib_x shorted to squib_y (1 or more shorted conditions) short between squib lines (loops) (squib_xx_ssqb_yy) (17) v thssqb 1.0 1.4 2.0 v vdiag supply diagnostics ($c0 command) vdiag supply voltage high threshold v dhi 15 17 18.3 v vdiag supply voltage low threshold v dlo 5.7 6.5 7.0 v vfire supply diagnostics vfire _1b and vfire_2b ($c5 command) vfire supply voltage high threshold v fdhi 15 17 18.3 v vfire supply voltage low threshold v flo 5.7 6.5 7.0 v vdiag supply diagnostics vdiag_1 and vdiag_2 (additional voltage thresholds) ($c5 command) vdiag supply voltage threshold 4 v vdiag_x v4 30.2 32.8 36.2 v vdiag supply voltage threshold 3 v vdiag_x v3 25.5 27.7 30.2 v vdiag supply voltage threshold 2 v vdiag_x v2 20.5 22.6 25.5 v vdiag supply voltage threshold 1 v vdiag_x v1 16 18.4 20.5 v vfire_rtn diagnostics ($c9 command) r _ rtn1 short-to-ground threshold (open ground connection) r rtn1 0.15 ? 0.6 ? r _ rtn2 short-to-ground threshold (open ground connection) r rtn2 0.15 ? 0.6 ? high-side safing sensor diagnostics ($c0 command) r _ hs valid resistor range 15 v v vdiag_x 35 v r hs 4.1 5.1 6.1 k ? r _ hs open threshold 15 v v vdiag_x 35 v r hso 6.1 7.2 9.0 k ? notes 16. xx = 1a, 1b, 2a, or 2b 17. xx and yy = 1a, 1b, 2a, or 2b table 3. static electrical characteristics (continued) characteristics noted under conditions 4.75 v v dd 5.25 v; 7.0 v v vfire_xx 35 v; v vdiag_x = v vfire_xx ; fen 1 = fen 2 = v dd ; r r_limit_x =10k ? 1%, r r_diag = 10 k ? 1%, -40 c t a +85 c, gnd = 0 unless otherwise noted. typical values noted reflect the approximate parameter means at t a = 25c under nominal conditions unless otherwise noted. characteristic symbol min typ max unit
analog integrated circuit device data 10 freescale semiconductor 33797 static electrical characteristics r _ hs short threshold r hss 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 i 1hso 270 360 410 a vfire_xa & vfire_xb current during high side safing test at short threshold vfire_1a & vfire_1b or vfire_2a & vfire_2b i 1hss 287 385 436 a high-side safing sensor diagnostics with 1 safing sensor in firing path connected to vfire_1a and vfire_2a terminals (guaranteed by design) ($c0 command) total vfire_xx current during high side safing test at open threshold vfire_1a, vfire_1b, vfire_2a & vfire_2b terminals i 2hso 574 705 835 a total vfire_xx current during high side safing test at short threshold vfire_1a, vfire_1b, vfire_2a & vfire_2b terminals i 2hss 605 748 892 a r _ hs valid resistor range 15 v v vdiag_x 35 v r 2hs 1.99 ? 2.93 k ? r _ hs open threshold 15 v v vdiag_x 35 v r 2hso 2.93 3.35 4.43 k ? r _ hs short threshold 15 v v vdiag_x 35 v r 2hss 1.41 1.61 1.99 k ? r_limit resistor diagnostics ($c8 command) r _ limit valid resistor range r rl 4.32 ? 45.3 k ? r _ limit open threshold (?out of range threshold?) r rlo 60 76 105 k ? r _ limit short-to-ground threshold (?out of range threshold?) r rls 3.0 3.5 4.31 k ? maximum external capacitance to ground c rl ? ? 20 pf r_diag resistor diagnostics ($c8 command) (18) r _ diag valid resistor range r rd 8.0 ? 13 k ? r _ diag open threshold (?out of range threshold?) r rdo 13 23 60 k ? r _ diag short-to-ground threshold (?out of range threshold?) r rds 3.0 5.4 8.0 k ? maximum external capacitance to ground c rd ? ? 20 pf notes 18. 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%. de sign 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 4 . table 3. static electrical characteristics (continued) characteristics noted under conditions 4.75 v v dd 5.25 v; 7.0 v v vfire_xx 35 v; v vdiag_x = v vfire_xx ; fen 1 = fen 2 = v dd ; r r_limit_x =10k ? 1%, r r_diag = 10 k ? 1%, -40 c t a +85 c, gnd = 0 unless otherwise noted. typical values noted reflect the approximate parameter means at t a = 25c under nominal conditions unless otherwise noted. characteristic symbol min typ max unit
analog integrated circuit device data freescale semiconductor 11 33797 static electrical characteristics table 4. resistance range vs. r_diag serial interface output logic low level (d0) i sink = -800 a v olow 0.0 ? 0.2 x v dd output logic high level (d0) i source = 800 a v ohigh 0.7 ? 1.0 x v dd input logic threshold (d1, cs , clk) v lthr 0.35 ? 0.65 x v dd d1 pull-down current i d1 -6.0 -10 -15 a clk pull-down current i clk -6.0 -10 -15 a cs pull-up current i csbar 10 20 30 a hi-z leakage (d0) i hi-z ? ? 10 a table 3. static electrical characteristics (continued) characteristics noted under conditions 4.75 v v dd 5.25 v; 7.0 v v vfire_xx 35 v; v vdiag_x = v vfire_xx ; fen 1 = fen 2 = v dd ; r r_limit_x =10k ? 1%, r r_diag = 10 k ? 1%, -40 c t a +85 c, gnd = 0 unless otherwise noted. typical values noted reflect the approximate parameter means at t a = 25c under nominal conditions unless otherwise noted. characteristic symbol min typ max unit r_diag i diag (nom) r th1 min/max r th2 min/max r th3 min/max r th4 min/max r th5 min/max r th6 min/max r th7 min/max r th8 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
analog integrated circuit device data 12 freescale semiconductor 33797 dynamic electrical characteristics dynamic electrical characteristics table 5. dynamic electr ical characteristics characteristics noted under conditions 4.75 v v dd 5.25 v; 7.0 v v vfire_xx 35 v; v vdiag_x = v vfire_xx ; fen 1 = fen 2 = v dd ; r r_limit_x =10k ? 1%, r r_diag = 10 k ? 1%, -40 c t a +85 c, gnd = 0 unless otherwise noted. typical values noted reflect the approximate parameter means at t a = 25c under nominal conditions unless otherwise noted. characteristic symbol min typ max unit serial interface clk cycle time (1/fclk) (19) t cyc 200 ? ? ns clk high time (19) v clk > v dd x 70% t hi 34 ? ? ns clk low time (19) v clk < v dd x 20% t lo 34 ? ? ns clock rise time (19) v clk = 20% v dd to 70% v dd , c load = 100 pf t rise ? ? 20 ns clock fall time (19) v clk = 70% v dd to 20% v dd , c load = 100 pf t fall ? ? 20 ns data out rise time (20) v do = 20% v dd to 70% v dd , c load = 100 pf t r ? ? 20 ns data out fall time (20) v do = 70% v dd to 20% v dd , c load = 100 pf t f ? ? 20 ns chip select setup time (20) csb before clk t lead 62 ? ? ns chip select hold time (20) clk before csb t lag 62 ? ? ns data in setup time (20) d1 valid before clk t su 30 ? ? ns data in hold time (20) d1 hold time after clk t h 30 ? ? ns data out access time (20) csb to d0 valid t a ? ? 62 ns data out disable time (20) csb to d0 hi-z t dis ? ? 62 ns data out valid time (20) clk to d0 valid, c load = 100 pf t v ? ? 75 ns data out hold time (20) d0 held after clk t ho 0.0 ? ? ns diagnostic delay time (between two successive commands) t diag 2.5 ? ? s notes 19. determined by design 20. guaranteed by characterization
analog integrated circuit device data freescale semiconductor 13 33797 dynamic electrical characteristics fet drivers turn-on delay time cs to 80% i hs t on ?? 72 s turn-off delay time cs to 20% i hs t off ?? 10 s diagnostic timing/resolution 5.0 v v vdiag_x 35 v, i hs i meas , 0 s t measure_time 6.375 ms, c squib_hi = 0.12 f, c squib_lo = 0.12 f t resolution 21.25 25 28.75 s diagnostic delay time squib resistance diagnostic delay time (21) from csb until transistor test results are valid, c squib_hi = 0.12 f, c squib_lo = 0.12 f t diag1 ??300 s squib open/short diagnostic delay time (21) from csb until squib open/short di agnostic results are valid, c squib_hi = 0.12 f, c squib_lo = 0.12 f t diag2 ? ? 3000 s vdiag supply diagnostic delay time from csb until vdiag diagnostic results are valid (21) t diag4 ? ? 3000 s v fire supply diagnostic delay time (21) 15 v v vdiag_x 35 v, from csb until high-side safing sensor diagnostic results are valid, c vdiag < 0.015 f t diag6 ? ? 1000 s high-side safing sensor diagnostic delay time (21) 15 v v vdiag_x 35 v, from csb until high-side safing sensor diagnostic results are valid, c vdiag < 0.015 f t diag7 ? ? 1000 s fet drivers high- and low-side driver transistor diagnostic delay time (21) 15 v v vdiag_x 35 v, from csb until transistor test results are valid, c squib_hi = 0.12 f, c squib_lo = 0.12 f, c vdiag < 0.015 f t diag9 ? ? 1000 s vfire_rtn diagnostic delay time (21) from csb until vfire_rtn diagnostic results are valid t diag10 ??300 s squib continuity di agnostic delay time (21) from csb until v thsqbcon diagnostic results are valid t diag11 ? ? 3000 s squib short between firing loops diagnostic delay time from csb until v thssqb diagnostic results are valid (21) t diag12 ? ? 3000 s fen input terminal minimum pulse width fen filter 12 14 16 s notes 21. guaranteed by characterization table 5. dynamic electrical characteristics (continued) characteristics noted under conditions 4.75 v v dd 5.25 v; 7.0 v v vfire_xx 35 v; v vdiag_x = v vfire_xx ; fen 1 = fen 2 = v dd ; r r_limit_x =10k ? 1%, r r_diag = 10 k ? 1%, -40 c t a +85 c, gnd = 0 unless otherwise noted. typical values noted reflect the approximate parameter means at t a = 25c under nominal conditions unless otherwise noted. characteristic symbol min typ max unit
analog integrated circuit device data 14 freescale semiconductor 33797 timing diagrams timing diagrams figure 4. driver timing diagram figure 5. freescale spi figure 6. alternative sci mode 80% 20% i hs t on t off chip select (/cs) cs cs clk misomsb654321lsb mosimsb654321lsb cs clk misomsb654321lsb mosimsb654321lsb
analog integrated circuit device data freescale semiconductor 15 33797 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 connection s, 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 terminal, is used to arm and fire a selected squib. 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-side and low-side output drivers are protected against temporary shorts to battery or ground. the current limit threshold is se t by an external resistor. functional terminal description introduction 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. serial clock (sclk) serial clock input for spi interface. data on the d1 terminal is clocked into the device on t he rising edge. data is clocked out of the device via the d0 terminal 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) serial data output from 33797 spi interface. fet driver 1a and 1b (fen_1) active high input signal to enable operation of squibs 1a and 1b fet drivers. all diagnostic functions are available while terminal 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 terminal is low. default state is low with no connection. device ground (gnd) device ground terminal for internal logic and diagnostic circuitry. device power (vdd) device power terminal 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 cu rrent limit for squibs 1a and 1b fet drivers. limit resistor 2a and 2b (r _ limit_2) external resistor to ground is used to set cu rrent limit for squibs 2a and 2b fet drivers. squib diagnostic 1a and 1b (vdiag_1) diagnostic terminals for the high-side safing sensors for squibs 1a and 1b, as well as the vfire supply voltage.
analog integrated circuit device data 16 freescale semiconductor 33797 functional description functional terminal description squib diagnostic 2a and 2b (vdiag_2) diagnostic terminals for the high-side safing sensors for squibs 2a and 2b, as well as the vfire supply voltage. squib sense xx (sense_xx) the sense terminals are used exclusively for diagnostics related to the squib, driver fets, or harness. commands using the sense terminals include: ? c1, c2, c3, c9 ?d<3:0> ?e<3:0> ?e9 ? 82/1x ? 83/2x independent of the system conf iguration, normal or cross coupled, the sense terminal, xx and squibhi, xx of a single ic are always connected to the same squib with the squibhi pin connected to the high terminal of the squib and the sense pin connected to the low terminal 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 termi nal to the high-side driver fet (see figure 7 ). cross-coupled applications used during cross-coupling applications involving two four-channel squib driver ics (s quib driver ic #1 and squib driver ic #2). sense_xx terminals from squib driver ic #1 are connected to their respective squib minus terminals (squib low/sqb_lo_xx) from squib driver ic #2 ( figure 8 ). sense_xx terminals are used to feed diagnostic signals back to squib driver ic #1 for determining squib resistance, short-to-battery/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 te rminal to the low-side driver fet. design notes diagnostics always have the form of a f orcing function and a measurement or sense function . in a cross couple configuration, most diagnostics are unaffected and are single commands except for $c2 low side fet continuity and $e<3:0> 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<3:0> 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 terminal. 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 terminals for squibs 1a, 1b, 2a, and 2b. these terminals 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 terminals for squibs 1a, 1b, 2a, and 2b. these terminals 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 terminals for squibs 1a, 1b, 2a, and 2b. these terminals 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 terminal and vfire_2b to vfire_2a terminal. squib fire power ground (vfire_rtn) return for squibs 1a, 1b, 2a and 2b. the terminals are tied to the source terminals of both low-side fet drivers, as well as the diagnostic circuitry. the rtn terminals are tied internally.
analog integrated circuit device data freescale semiconductor 17 33797 functional description functional terminal description figure 7. standard squib firing figure 8. cross-coupled squib firing vfire dri ver control 1a squib 1 vboost + - spi interface cs1 sense_1a $c2 command checks this squib ic #1 vfire dri ver control 1a squib 2 squib 1 vboost + - + - squib asic #1 spi interface cs1 cs2 dri ver control vfire squib asic #2 sense_1a sense_1a $c2 command checks this
analog integrated circuit device data 18 freescale semiconductor 33797 functional description functional device operation 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 terminals. 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 regist er 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 8 ). 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 csb, the ic config ures 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 6 ). 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 (csb goes high), then d0 is a high-impedance output. response bit 7 of command $c8 (refer to table 7 , page 22 ) 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 7 , standard squib firing). the sense_xx (1a, 1b, 2a, 2b) terminal is connected to sqb_lo_xx (1a, 1b, 2a, 2b). squib diagnostics are conducted using this terminal. in the standard mode, the $c2 (squib_lo_xx_cont) command will be used to check continuity of the low-side driver from the sqb_lo_xx terminal (1a, 1b, 2a, 2b) to the low-side driver fet ( figure 7 ). the low-side driver continuity is checked during the continuity test. the driver continuity information will be cleared after the information is transmitted on the next valid spi command. example?standard squib command spi sequence from microcontroller tx: request squib short-to-battery/gnd diagnostic mea- surement ($c1). rx: previous executed command information. tx: request squib 1a resistance measurement ($d0? $d3). rx: receive results from short-to-battery/gnd diagnos- tics. tx: request squib 1b resistance measurement ($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 trans- ferred from the squib ic (clear on rising edge of chip select).
analog integrated circuit device data freescale semiconductor 19 33797 functional description functional device operation tx: request loop-to-loop short command ($e0?$e3) rx: previous executed command information. tx: request another command sequence. rx: receive loop-to-loop results from test. cross-coupled squib ic function 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 17 .) through the spi interface, the squib ic will maintain the capability to conduct standard diagnostics (s hort-to-battery, short-to- ground, short between squibs, and squib diagnostics) between two different squib ics. the squib ic must maintain the capability to fire the squi b 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 lo w-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- an d 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 r r_ diag , r r_ limit_x , high side, v vfire_xx , v vfire_ rtn , v transtx , squib current timing measurement, and fen_1 and fen_2 diagnostics. the sense_1a (1b, 2a, or 2b) terminal squib ic #1 is connected to sqb_lo_1a (1b, 2a, or 2b) terminal 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 17 ). 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 cross-coupled mode, the squib driver ic #2 $c2 (squib_lo_1a_cont, [1b, 2a, or 2b]) command will be used to check continuity of the low-side driver from the sqb_lo_1a (1b, 2a, or 2b) terminal to the low-side driver fet. the low-side driver continuity is checked during the continuity test. the driver c ontinuity information will be cleared after the information is transmitted on the next valid spi command. example?cross-coupled squib command spi sequence from microcontroller tx: squib ic #1 request squib 1a resistance measurement ($d0). rx: previous executed command information. tx: run another command on the same squib ic #1. rx: receive measured squib 1a resistance information. tx: squib ic #1 request continuity command ($c2). rx: previous executed command information. tx: squib ic #2 request continuity command ($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 terminals to be high and two separate 8-bit writes be made to the shift register. with fen_1 terminal high, squibs 1a and 1b can be armed and fired. with fen_2 terminal high, squibs 2a and 2b can be armed an d 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 6 ) or all squibs can be fired at once (refer to table 7 ). all arm and 5x (fire) commands will be echoed back on the spi data output. table 6. squib firing commands hex code command description a0 arm squib drivers 1a and 1b a1 arm squib drivers 2a and 2b
analog integrated circuit device data 20 freescale semiconductor 33797 functional description functional device operation 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 mo st significant bits of the first write. the four least signific ant 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 firs t 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 terminal pulled low. ? having the thermal shutdown limit exceeded (once minimum firing duration requirement has been met; refer to note 4 in the ma ximum ratings table, page 5 ). ? having the fen terminal pulled low. note that the code sequences allow any combination of drivers to be turned on or off. once fired, the current lim it measurement register increments when the squib current is measured and is above the i meas threshold during the timer activation. the fen_1 or fen_2 terminal must be high to enable firing of the drivers. if fire command is active and the fen (1 or 2) terminal 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, page 28 ). if fire command is active and the fen (1 or 2) terminal is pulled high, the fet driver will turn on. byte #1 byte #2 squib b high side squib b low side squib a high side squib a low side squib 2b squib 2a squib 1b squib a1 a0 arm squib drivers 1a and 1b a1 arm squib drivers 2a and 2b a2 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 table 6. squib firing commands
analog integrated circuit device data freescale semiconductor 21 33797 functional description functional device operation 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 possib le and isolated from logic and diagnostic grounds. table 7. 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 00 nop 0 0 0 0 0 0 0 0 70 squib 1a current measurement time sqb_1a bit 7 ms 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 71 squib 1b current measurement time sqb_1b bit 7 ms sqb_1b bit 6 sqb_1b bit 5 sqb_1b bit 4 sqb_1b bit 3 sqb_1b bit 2 sqb_1b bit 1 sqb_1b bit 0 ls 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 sqb_2b current limit status sqb_2a current limit status sqb_1b current limit status sqb_1a current limit status 7f thermal shutdown status thermal sd 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 v diag _ 2 vdhi v diag _ 2 vdlo rsslo rsshi v diag _ 1 vdhi v diag _ 1 vdlo c1 squib short-to- ground/short-to- battery diagnostics sqb _ 2b no_sh_ gnd sqb _ 2b no_sh_ batt sqb _ 2a no_sh_ gnd sqb _ 2a no_sh_ batt sqb _ 1b no_sh_ gnd sqb _ 1b no_sh_ batt sqb _ 1a no_sh_ gnd sqb _ 1a no_sh_ batt c2 low-side driver continuity status 0 0 0 0 sqb_lo_2b_ cont sqb_lo_2a cont sqb_lo_1b cont sqb_lo_1a cont c3 harness short-to- ground/ short-to- battery 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 sqb _ 1b open no_sh_ gnd sqb _ 1b open no_sh_ batt sqb _ 1a open no_sh_ gnd sqb _ 1a open no_sh_ batt 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 c5 vfire_1b and vfire_2b voltage 0 0 0 v fire _b tested x x v hi v lo
analog integrated circuit device data 22 freescale semiconductor 33797 functional description functional device operation c6 vdiag_1 and vdiag_2 diagnostics v diag _ 2 v4 v diag _ 2 v3 v diag _ 2 v2 v diag _ 2 v1 v diag _ 1 v4 v diag _ 1 v3 v diag _ 1 v2 v diag _ 1 v1 c8 fen status, r _ limit_x, r _ diag status, ic type 1 r _ limit _ 2 no_fault r _ limit _ 1 no_fault r _ diag no_ fault fen 2 latch status fen 1 latch status fen 2 status fen 1 status c9 vfire_rtn status (open ground) 0 0 0 0 0 0 v fire _ rtn_2 vf2low v fire _ rtn_1 vf1low d0 squib 1a resistance sqb_1a rc8 sqb_1a rc7 sqb_1a rc6 sqb _ 1a rc5 sqb _ 1a rc4 sqb _ 1a rc3 sqb _ 1a rc2 sqb _ 1a rc1 d1 squib 1b resistance sqb_1b rc8 sqb_1b rc7 sqb_1b rc6 sqb _ 1b rc5 sqb _ 1b rc4 sqb _ 1b rc3 sqb _ 1b rc2 sqb _ 1b rc1 d2 squib 2a resistance sqb_2a rc8 sqb_2a rc7 sqb_2a rc6 sqb _ 2a rc5 sqb _ 2a rc4 sqb _ 2a rc3 sqb _ 2a rc2 sqb _ 2a rc1 d3 squib 2b resistance sqb_2b rc8 sqb_2b rc7 sqb _ 2b rc6 sqb _ 2b rc5 sqb _ 2b rc4 sqb _ 2b rc3 sqb _ 2b rc2 sqb _ 2b rc1 e0 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 table 7. diagnostic bit definitions (continued)
analog integrated circuit device data freescale semiconductor 23 33797 functional description functional device operation table 8. command programming and diagnostic bit definitions hex code 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 3x current measurement register reset command for squib x current 1=on 0 0 1 1 sqb_2b data/timer reset sqb_2a data/timer reset sqb_1b data/timer reset sqb_1a data/timer reset data out squib x current register reset status 0 0 1 1 sqb_2b data/timer reset sqb_2a data/timer reset sqb_1b data/timer reset sqb_1a data/timer reset 80 unlock for fen 1 counter registers programming. 1000 0 000 response data output: command echoed 1 0 0 0 0 0 0 0 xx 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 81 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 22. the second byte for command programming will be treated as a nop if any fet is firing. t he programming commands have to be sequential or they will be treated as a nop.
analog integrated circuit device data 24 freescale semiconductor 33797 functional description functional device operation 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 xx programming command for fen 2 counter 1=on 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 response data out fen 2 counter programming status 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 82 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 1x high-side driver transistor test command 0 0 0 1 sqb_ 2b high-side driver ?on? sqb_ 2a high-side driver ?on? sqb_1b high-side driver ?on? sqb_1a high-side driver ?on? response data out high-side driver transistor status v trantst1 0 0 0 0 sqb_2b hsdstat_2b sqb_2a hsdstat_2a sqb_1b hsdstat_1b sqb_1a hsdstat_1a 83 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 2x low-side driver transistor test command 0 0 1 0 sqb_ 2b low-side driver ?on? sqb_2a low-side driver ?on? sqb_1b low-side driver ?on? sqb_1a low-side driver ?on? response data out low-side driver transistor status v trantst2 0 0 0 0 sqb_2b lsdstat_ 2b sqb_2a lsdstat_ 2a sqb_1b lsdstat_1b sqb_1a lsdstat_1a notes 23. the second byte for command programming will be treated as a nop if any fet is firing. t he programming commands have to be sequential or they will be treated as a nop. hex code command description command programming input and diagnostic data out (available on next command) (24) bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 table 8. command programming and diagnostic bit definitions (continued)
analog integrated circuit device data freescale semiconductor 25 33797 functional description protection and diagnosis features 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 7, diagnostic bit definitions , and table 8, command programming and diagnostic bit definitions , 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 terminal 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 terminal and will cause an ?out of range resistor value? indication. r _ limit_x and r _ diag data results if r_limit_x is open, shorte d 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 terminals. high-side safing sensor diagnostics ($c0 command) this function monitors the vfire_xx terminal connection to the vdiag_x terminal. the high-side safing function is attached to the vfire _1a and vfire_2a terminals. the high-side safing function is not available on the vfire _1b and vfire_2b terminals. when enabled, this diagnostic circuit will typically draw less than 500 a from the vfire supply voltage source. internal window comparators will monitor the voltage difference between the vdiag_x terminal and the vfire_xx terminal, and will provide two bits of data to indicate if the terminal 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 di agnostic 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 that neither an open fault nor a shorted fault condition will be indicated. a closed safing sensor will be indicated as a short, and a loss of the connection between the vdiag_x terminal and the vfire_xx terminal will be indicated as an open. any external capacitance on the vfire_xx terminal will affect the time needed to settle to an accurate value. 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: $69 echo to diagnose the spi integrity 0 1 1 0 1 0 0 1 notes 24. the second byte for command programming will be treated as a nop if any fet is firing. t he programming commands have to be sequential or they will be treated as a nop. table 8. command programming and diagnostic bit definitions (continued)
analog integrated circuit device data 26 freescale semiconductor 33797 functional description protection and diagnosis features high-side safing sensor diagnostic data results if the vfire_xx terminal is shorted to the vdiag_x terminal, the rsslo bit will be set to ?1? and the rsshi bit will be set to ?1?. if the vfire_xx terminal has no connection to the vdiag_x terminal, the rsslo bit will be set to ?0? and the rsshi bit will be set to ?0?. standard operation with a safing sensor resistor will have the rsshi bit set to ?1? and the rsslo bit set to ?0?. firing supply voltage (vdiag_x) diagnostics ($c0 command) this function monitors the voltage on the vdiag_x terminal. the supply voltage is compared to two thresholds (nominal and minimum) and will provide two bits of data to indicate if the terminal voltage is above, below, or in between the predetermined threshold levels. there is one diagnostic circuit for each vdiag_x terminal. vdiag_x supply voltag e diagnostic data results if the vdiag_x voltage is abov e 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 lo w 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 ($c5 command) this function monitors the voltage on the vfire_xx terminal. the supply voltage is compared to two thresholds (nominal and minimum) and will provide two bits of data to indicate if the terminal voltage is above, below, or in between the predetermined threshold levels. there is one diagnostic circuit for each vfire_xx terminal. vfire_xx supply voltag e diagnostic data results if the vfire_xx voltage is ab ove the high limit, bits vfhi and vflo will both be set to ?1?. if the vfire_xx voltage is between the high limit and the low limit, bit vfhi will be set to ?0? and vflo will be set to ?1 ?. if the vfire_xx voltage is below the low limit, bits vfhi and vflo will both be set to ?0?. firing supply volta ge diagnostics, vdiag_x v1, v2, v3, v4 ($c6 command) the vdiag_x v1, v2, v3, v4 function monitors voltage on the vdiag terminals. the voltage being measured is then compared to four thresholds and will provide four bits of data to indicate if the terminal voltage is above, below, or between the predetermined threshold levels. there is one diagnostic circuit for each vdiag_x terminal. vdiag_x voltage diagnostic data results i f the vdiag_x voltage is above the threshold limit, the 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?. vfire_rtn diagnostics ($c9 command) this function monitors the resistance on the vfire_rtn terminal for open terminal connections. the vfire_rtn voltage is compared to a threshold to determine if the vfire_rtn terminal connection between the terminal and the printed circuit board is shorted or open. vfire_rtn diagnostic data results if the vfire_rtn terminal is above the threshold limit (open), the vfire_rtn x vfxlow will be set to ?1?. if the vfire_rtn terminal is below the threshold limit (shorted), the vfire_rtn x vfxlow will be set to ?0?. vfire return tests are disabled during firing. design notes for all standard or cross-coupled squib ic configurations, the sqb_lo_xx terminal must be tied to a sense_xx terminal for either squib ic #1 or squib ic #2 (see figure 7 and figure 8 ). an active 600 a current sink is located in the sense_xx terminal. the sink current is used to pull the charge off the external emc/filter caps after a diagnostic measurement has been made. squib short-to-battery/ground diagnostics ($c1 command) this function monitors the voltage on the sense_xx terminals. the voltage is compared to two thresholds (minimum and maximum) and will provide two bits of data to indicate if the terminal 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 terminal is activated, sourcing current from the sqb_hi_xx to the sense_xx terminal. when resistive measurement legs to comparators located in the sense_xx terminal 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 terminal 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 terminal has an external current path that causes the terminal to be
analog integrated circuit device data freescale semiconductor 27 33797 functional description protection and diagnosis features 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 terminal is shorted to battery, the bit no_s h_batt will be set to ?0?. if a sqb _ lo_xx, sqb_hi_xx, or sense_xx terminal is shorted to ground, the bit no _sh_gnd will be set to ?0?. during standard operatio n, 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 terminal as a bias. if the sqb_lo_xx and sqb_hi_xx terminals 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 terminals for ?short to ground? and ?short to battery? conditions. this function monitors the voltage on the sense_xx terminals. the voltage is compared to two thresholds (minimum and maximum) and will provide two bits of data to indicate if the terminal 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 terminals together. a 2.7 ma current source lo cated in the sqb_hi_xx terminal is activated, sourci ng current from the sqb_hi_xx to the sqb_lo_xx terminal to the sense_xx terminal. when resistive measurement legs to comparators located in the sense_xx terminal are acti vated, 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 terminal 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 terminal has an external current path that causes the terminal 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 terminal 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 terminal is shorted to ground, the bi t 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 terminal as a bias. if the sqb_lo_xx and sqb_hi_xx terminals 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 conditi on. the standard squib short- to-battery/ground diagnostics ($c1) can be executed to determine if the fault condition is on the sqb_hi_xx terminal or the sqb_lo_xx terminal. continuity test for the low-side driver sqb_lo_xx connection ($c2 command) (low-side driver continuity status) low-side driver continuity is checked during the continuity test diagnostics. this function is used to check continuity at the sqb_lo_xx terminal connection. when enabled, a 2.0 ma current source located in the sqb_hi_xx terminal is activated sourcing current from the sqb_hi_xx to the sqb_lo_xx terminal. for a standard connection, the squib_lo_xx_con bit will be set to ?1?. with an open circuit connection, the squib_lo_xx bit will be set to ?0?. the driver continuity information will be cleared after the information is transmitted on the next valid spi command. squib resistance diagnostics ($d0?$d3 command) this function monitors squib resistance. when enabled, a diagnostic current derived from r _ diag is passed through the selected squib. the resulting voltage across the squib is amplified and passed to an 8-bit voltage level detector. the eight bits of data will indicate if the selected squib has a resistance value above or below predetermined thresholds. the value of r _ diag can be varied to allow the detection range to be altered. increasing the value of r _ diag will reduce the diagnostic current; thus, a higher squib resistance will be needed to reach the same r th points. in the case that r _ diag is a short-to-ground, the diagnostic current through the squib resistance will typically be less than 50 ma. squib resistance diagnostic data results a comparator result bit set to ?1? indicates that the input voltage is above the threshold re sistance for that bit. thus an open squib would cause all bits to be set to ?1?; likewise, a shorted squib will cause all bits to be set to ?0?. squib resistance tests are disabled during firing.
analog integrated circuit device data 28 freescale semiconductor 33797 functional description protection and diagnosis features squib diagnostics sh orts between squib lines (firing loops) ($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 terminal is activated sourcing current fr om the selected sqb_hi_xx to the sense_xx terminal. the resulting voltage is checked on all other squib lines to determine if the squib lines are shorted. in applications using mo re than one squib driver ic, a separate command can also be issued to check all squibs for shorted squib lines. squib diagnostics sh orts 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 (r st ) the reset terminal has an internal current pull-down of typically 40 a. while this terminal 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 v dd 4.1 v, the system reset bar thre shold 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 terminal is low, firing of the fet drivers is disabled. all internal diagnostic functions and results will be available through the serial interface. the fen terminal must be pulled high to enable firing of the fet drivers. also, the terminal stat e 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 7, diagnostic bit definitions , page 22 .) 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 terminal is acti ve (?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 transiti ons 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 terminal transitions from ?0? to ?1?. the programmable counter delay will be set through an spi command during module power-up/prove- out. the default for the counter will be 0 ms. the bits fen 1 and fen 2 status are a reflection of their respective terminals . the counter will be reset to 0-sec time during a reset condition. notes 1. status information will be required to read counter- programmed 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 8 , page 23 .) 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 8 ). 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 bot h squib channels. the low-side current limit is never less than the high-side current limit. table 9. r r_limit_x current limit r r_limit_x v vfire = 7.0 v v vfire = 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
analog integrated circuit device data freescale semiconductor 29 33797 functional description protection and diagnosis features example of current limit conditions: r r_limit_x =10 k ? , i hs =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 r r_limit_x conditions <4.32 k ? or shorted to ground, the current limit will default to the r r_limit_x = 10 k ? current limit, not to e xceed. with r r_limit_x resistance value >60 k ? or open, the current limit will default to the r r_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 i meas is above the threshold for each squib. (refer to dynamic electrical characteristics table, page 12 .) 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 i meas threshold during the timer activation, a status bit will be set to ?1?. if the current measured is not above the i meas 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 measurement s can be made. initial squib ic power-up will reset the timi ng 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 i meas , the current limit is activated and the status bit will be set to ?1?. if the firing current is below i meas , 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 8 . 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 sq uib 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 t on 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 bi t 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 temp renable (min) is reached (thermal shutdown status ?0?). v trantstx, 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 terminals to be low and two separate 8- bit write commands to be made to the shift register. with the fen_1 and fen_2 terminals 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 se cond 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 8 , page 24 ). a load from the sqb_hi_xx terminal to the sense_xx terminal 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 8 ). 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 st op 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.
analog integrated circuit device data 30 freescale semiconductor 33797 functional description protection and diagnosis features 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 ac tivate (turn ?on?) during the diagnostic test. diagnostic data will be shifted from the shift register during the nex t 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.
analog integrated circuit device data freescale semiconductor 31 33797 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. notes: 1. all dimensions are in millimeters. 2. dimensioning and tolerancing per asme y14.5m, 1994. 3. datums b and c to be determined at the plane where the bottom of the leads exit the plastic body. 4. this dimension does not include mold flash, protrusion or gate burrs. mold flash, protrusion or gate burrs shall not exceed 0.15 mm per side. this dimension is determined at the plane where the bottom of the leads exit the plastic body. 5. this dimension does not include interlead flash or protrusions. interlead flash and protrusions shall not exceed 0.25 mm per side. this dimension is determined at the plane where the bottom of the leads exit the plastic body. 6. this dimension does not include dambar protrusion. allowable dambar protrusion shall not cause the lead width to exceed 0.4 mm per side. dambar cannot be located on the lower radius or the foot. minimum space between protrusion and adjacent lead shall not less than 0.07 mm. 7. exact shape of each corner is optional. 8. these dimensions apply to the flat section of the lead between 0.10 mm and 0.3 mm from the lead tip. 9. the package top may be smaller than the package bottom. this dimension is determined at the outermost extremes of the plastic body exclusive of mold flash, tie bar burrs, gate burrs and inter-lead flash, but including any mismatch between the top and bottom of the plastic body. c l 10.9 7.4 1 16 17 32 0.10 a 2.35 seating plane 0.9 section b-b 0.65 r0.08 min b a pin 1 id (0.29) 0.38 0.25 (0.203) plating base metal section a-a rotated 90 clockwise 8 0.19 0.22 9 5 0.13 m ca m b 6 a c 7.6 11.1 9 4 10.3 5.15 a 32x 30x 2.65 0.3 a 2x 16 tips b c b 0.29 0.13 0.5 0 8 0 0.25 gauge plane min ek suffix (32-lead soic) plastic package 98arh99137a
MC33797 rev 2.0 07/2005 information in this document is provided solely to enable system and software implementers to use freescale semiconduc tor products. there are no express or implied copyright licenses granted hereunder to design or fabricate any integrated circuits or integrated circuits based on the information in this document. freescale semiconductor reserves the right to make changes without further notice to any products herein. freescale semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does freescale semiconductor assume any liability ar ising out of the application or use of any product or circuit, and specifically discl aims any and all liability, including without limitation consequential or incidental damages. ?typical? parameters that may be provided in freescale semiconductor data s heets and/or specifications can and do vary in different applications and actual performance may vary over time. all operating parameters, including ?typicals?, must be validated for each customer application by customer?s technical experts. freescale se miconductor does not convey any license under its patent rights nor the rights of others. freescale semiconductor products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the fa ilure of the freescale semiconductor product could create a situation where personal injury or death may occur. should a buyer purchase or use freescale semiconductor products for any such unintended or unauthorized application, the buyer shall i ndemnify and hold freescale semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that freescale semiconductor was negligent regarding the design or manufacture of the part. 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., 2005. all rights reserved. how to reach us: home page: www.freescale.com e-mail: support@freescale.com usa/europe or locations not listed: freescale semiconductor technical information center, ch370 1300 n. alma school road chandler, arizona 85224 +1-800-521-6274 or +1-480-768-2130 support@freescale.com europe, middle east, and africa: freescale halbleiter deutschland gmbh technical information center schatzbogen 7 81829 muenchen, germany +44 1296 380 456 (english) +46 8 52200080 (english) +49 89 92103 559 (german) +33 1 69 35 48 48 (french) support@freescale.com japan: freescale semiconductor japan ltd. headquarters arco tower 15f 1-8-1, shimo-meguro, meguro-ku, tokyo 153-0064 japan 0120 191014 or +81 3 5437 9125 support.japan@freescale.com asia/pacific: freescale semiconductor hong kong ltd. technical information center 2 dai king street tai po industrial estate tai po, n.t., hong kong +800 2666 8080 support.asia@freescale.com for literature requests only: freescale semiconductor literature distribution center p.o. box 5405 denver, colorado 80217 1-800-441-2447 or 303-675-2140 fax: 303-675-2150 ldcforfreescalesemiconductor@hibbertgroup.com

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