View MC33794_4070937.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

gpx 33794 monitor (opt) field electrodes (e1 through e9) iso-9141 bus 5.0 v analog_in analog_in analog_in analog_in analog_in v pwr iso_tx iso_rx watchdog electrode select shield disable mcu simplified application diagram lamp_out lamp_sense lp_cap level v dd _mon pwr_mon lamp_mon iso_in iso_out wd_in lamp_ctrl dis_shield a, b, c, d lamp_gnd test r_osc agnd gnd v dd iso-9141 signal ref_a ref_b e1 e9 shield v pwr v cc reset rst motorola semiconductor technical data this document contains certain information on a new product. specifications and information herein are subject to change without notice. ? motorola, inc. 2004 document order number: MC33794/d rev 7.0, 04/2004 33794 advance information ordering information device temperature range (t a ) package MC33794dh/r2 -40c to 85c 44 hsop MC33794dwb/r2 54 soicw-ep electric field imaging device electric field imaging device the 33794 is intended for applications where noncontact sensing of objects is desired. when connected to external el ectrodes, an electric field is created. the 33794 is intended for use in detecting objects in this electric field. the ic generates a low-frequency sine wave. the frequency is adjustable by using an external resistor and is optimized for 120 khz. the sine wave has very low harmonic content to reduce harmonic interference. the 33794 also contains support circuits for a microcontroller unit (mcu) to allow the construction of a two-chip e-field system. features ? supports up to 9 electrodes and 2 references ? shield driver for driving remote electrodes through coaxial cables ? +5.0 v regulator to power external circuit ? iso-9141 physical layer interface ? lamp driver output ? watchdog and power-on reset timer ? critical internal nodes scaled and selectable for measurement ? high-purity sine wave generator tunable with external resistor dh suffix case 1291-01 44-lead hsop dwb suffix case 1390-01 54-lead soicw-ep 33794 simplified application diagram f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
33794 motorola analog integrated circuit device data 2 figure 1. 33794 simplified internal block diagram control logic mux out osc mux in rect lpf gain and offset attn lamp ckt iso-9141 por/ wd v cc reg v dd reg clk r_osc dis_shield shield lp_cap level signal lamp_sense lamp_mon lamp_out iso_in iso_out lamp_ctrl lamp_gnd v dd _ mon pwr_mon gnd and heat sink agnd v pwr wd_in rst v cc v dd e1 ? e9 + ref_a ? ref_b test a,b,c,d 4 5.6 k ? 47 k ? 39 k ? 10 nf 22 k ? (nominal) iso-9141 5.6 k ? f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
motorola analog integrated circuit device data 33794 3 heat sink gnd hsop pin function description pin pin name formal name definition 1 v cc 5.0 v regulator output this output pin requires a 47 f capacitor and provides a regulated 5.0 v for the mcu and for internal needs of the 33794. 2, 5, 27, 43 nc no connect these pins may be used at some future date and should be left open. 3 agnd analog ground this pin is connected to the ground return of the analog circuitry. this ground should be kept free of transient electrical no ise like that from logic switching. its path to the electrical current return poin t should be kept separate from the return for gnd. 4 shield shield driver this pin connects to cable shield s to cancel cable capacitance. 6, heat sink gnd ground this pin and metal backing is the ic power return and thermal radiator/conductor. 7 test test mode control this pin is normally connected to circ uit ground. there are special operating modes associated with this pin when it is not at ground. 8?16 e1?e9 electrode connections these are the electrode pins. they are conn ected either directly or through coaxial cables to the electrodes for measurem ents. one of these electrodes can be selected at a time for capacitance meas urement. all of the other unselected electrodes are grounded by an internal switch. the signal at the selected electrode pin is routed to the shield driver amplifier by an internal switch. all of the coaxial cable shields should be isolated from ground and connected shield. 17, 18 ref_a, ref_b reference connections these pins can be individually selected like e1 through e9. unlike e1 through e9, these pins are not grounded when not selected. the purpose of these pins is to allow known capacitors to be measured. by using capacitors at the low and high end of the expected range, absolute values for the capacitance on the electrodes can be computed. 19 iso_out iso-9141 output this pin translates iso-9141 receive leve ls to 5.0 v logic levels for the mcu. 20 iso_in iso-9141 input this pin accepts data from the mcu to be sent over the iso-9141 communications interface. it translates the 5.0 v logic levels from the mcu to transmit levels on the iso-9141 bus. v cc e5 e6 e7 e8 e9 ref_a ref_b iso_out iso_in iso-9141 lamp_ctrl gnd test e1 e2 e3 e4 agnd shield nc nc v pwr b c d dis_shield lamp_mon lamp_sense nc lamp_out lamp_gnd wd_in rst r_osc lp_cap pwr_mon level signal a v dd v dd_ mon clk nc 1 12 13 14 15 16 17 18 19 20 21 22 6 7 8 9 10 11 3 4 5 2 44 33 32 31 30 29 28 27 26 25 24 23 39 38 37 36 35 34 42 41 40 43 f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
33794 motorola analog integrated circuit device data 4 21 iso-9141 iso-9141 bus this pin connects to the iso-9141 bus. it provides the drive and detects signaling on the bus and translates it from the bus level to logic levels for the mcu. 22 lamp_ctrl lamp control this signal is used to control the lamp driver. a high logic level turns on the lamp 23 rst reset this output is intended to generate the reset function of a typical mcu. it has a delay for power-on reset, level detectors to force a reset when v cc is out-of- range high or low, and a watchdog timer that will force a reset if wd_in is not asserted at regular intervals. timing is de rived from the oscill ator and will change with changes in the resistor attached to r_osc. 24 wd_in watchdog input this pin must be asserted and deasserted at regular interval in order to prevent rst from being asserted. by having the mcu program perform this operation more often the allowed time, a check that the mcu is running and executing its program is assured. if this doesn?t occur, the mcu will be reset. if the watchdog function is not desired, this pin may be connected to cl k to prevent a reset from being issued. 25 lamp_gnd lamp ground this is the ground for the current from the lamp. the current into lamp_out flows out through this pin. 26 lamp_out lamp driver this is an active low output capable of sink ing current of a typical indicator lamp. one end of the lamp should be connected to a positive supply (for example, battery voltage) and the other side to this pin. t he current is limited to prevent damage to the ic in the case of a short or surge during lamp turn-on or burn-out. 28 lamp_sense lamp sense this pin is normally connected to the lamp _out pin. the voltage at this pin is reduced and sent to lamp_mon so the voltage at the lamp pin is brought into the range of the analog-to-digital converter (adc) in the mcu. 29 lamp_mon lamp monitor this pin is connected through a voltage divider to the lamp_sense pin. the voltage divider scales the voltage at this pin so that battery voltage present when the lamp is off is scaled to the range of the mcu adc. with the lamp off, this pin will be very close to battery voltage if t he lamp is not burned out and the pin is not shorted to ground. this is useful as a lamp check. 30 dis_shield shield driver disable this pin is used to turn off the shield si gnal. the purpose of doing this is to be able to detect that the shield signal is not work ing or the connection to the coax shields is broken. if either of these conditions ex ists, there will be little or no change in the capacitance measured when the dis_shield is asserted. if the shield output is working and properly connected, the capacit ance of the coax will not be cancelled when this pin is asserted and the measur ed capacitance will appear to change by approximately the capacitance between the center conductor and the shield in the coax. 34?31 a, b, c, d selector inputs these input pins control which electrode or reference is active. selection values are shown in table 1, electrode selection, page 14. 35 signal undetected signal this is the undetected signal being applied to the detector. it has a dc level with the low radio frequency signal superimposed on it. care must be taken to minimize dc loading of this signal. a shift of dc wi ll change the center point of the signal and adversely affect the detection of the signal. 36 level detected level this is the detected, amplified, and offs et representation of the signal voltage on the selected electrode. filtering of the re ctified signal is performed by a capacitor attached to lp_cap. 37 pwr_mon power monitor this is connected through a voltage divider to v pwr . it allows reduction of the voltage so it will fall within the range of the adc on the mcu. 38 lp_cap low-pass filter capacitor a capacitor on this pin forms a low pass filt er with the internal series resistance from the detector to this pin. this pin can be used to determine the detected level before amplification or offset is applied. a 10 nf capacitor connecte d to this pin will smooth the rectified signal. more capacit ance will increase the response time unnecessarily. hsop pin function description (continued) pin pin name formal name definition f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
motorola analog integrated circuit device data 33794 5 39 r_osc oscillator resistor a resistor from this pin to circuit ground determines the operating frequency of the oscillator. the 33794 is optimized for operation around 120 khz. 40 clk clock this pin provides a square wave output at the same frequency as the internal oscillator. the edges of the square wave coincide with the peaks (positive and negative) of the sine wave. 41 v dd_ mon v dd monitor this is connected through a voltage divider to v dd . it allows reduction of the voltage so it will fall within the range of the adc on the mcu. 42 v dd v dd capacitor a capacitor is connected to this pin to filter the internal analog regulated supply. this supply is derived from v pwr . 44 v pwr positive power supply input 12 v power applied to this pin will be converted to the regulated voltages needed to operate the part. it is also converted to 5.0 v (v cc ) and 8.5 v (v dd ) to power the mcu and external devices. hsop pin function description (continued) pin pin name formal name definition f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
33794 motorola analog integrated circuit device data 6 lamp_out 1 pwr_mon lp_cap r_osc nc nc nc nc clk v dd_ mon v dd v pwr level 11 12 13 14 15 16 17 18 19 20 9 10 21 22 23 24 25 26 27 6 7 8 4 5 dis_shield d c b a signal nc lamp_sense lamp_mon nc lamp_gnd nc 2 3 54 44 43 42 41 40 39 38 37 36 35 46 45 34 33 32 31 30 29 28 49 48 47 51 50 53 52 rst wd_in nc e3 e2 e1 test nc nc gnd nc shield agnd v cc e4 ref_a e9 e8 e7 e6 e5 nc iso_out ref_b nc iso_in nc lamp_ctrl iso-9414 soicw-ep pin function description pin pin name formal name definition 1 rst reset this output is intended to generate the reset function of a typical mcu. it has a delay for power-on reset, level detectors to force a reset when v cc is out-of- range high or low, and a watchdog timer that will force a reset if wd_in is not asserted at regular intervals. timing is derived from the oscill ator and will change with changes in the resistor attached to r_osc. 2 wd_in watchdog in this pin must be asserted and deasserted at regular interval in order to prevent rst from being asserted. by having the mcu program perform this operation more often the allowed time, a check that th e mcu is running and executing its program is assured. if this doesn?t occur, the m cu will be reset. if the watchdog function is not desired, this pin may be connected to clk to prevent a reset from being issued. 3, 5, 7, 20?23, 31, 33, 34, 48?50, 52 nc no connect these pins may be used at some future date and should be left open. 4 lamp_gnd lamp ground this is the ground for the current from the lamp. the current into lamp_out flows out through this pin. 6 lamp_out lamp driver this is an active low output capable of sink ing current of a typical indicator lamp. one end of the lamp should be connected to a positive supply (for example, battery voltage) and the other side to this pin. the current is limited to prevent damage to the ic in the case of a short or surge during lamp turn-on or burn-out. 8 lamp_sense lamp sense this pin is normally connected to the la mp_out pin. the voltage at this pin is reduced and sent to lamp_mon so the voltage at the lamp pin is brought into the range of the analog-to-digital converter (adc) in the mcu. 9 lamp_mon lamp monitor this pin is connected through a voltage divider to the lamp_sense pin. the voltage divider scales the voltage at this pin so that battery voltage present when the lamp is off is scaled to the range of the mcu adc. with the lamp off, this pin will be very close to battery voltage if the lamp is not burned out and the pin is not shorted to ground. this is useful as a lamp check. f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
motorola analog integrated circuit device data 33794 7 10 dis_shield shield driver this pin is used to turn off the shield si gnal. the purpose of doing this is to be able to detect that the shield signal is not working or the connection to the coax shields is broken. if either of these conditions exis ts, there will be little or no change in the capacitance measured when the dis_shield is asserted. if the shield output is working and properly connected, t he capacitance of the coax will not be cancelled when this pin is asserted and the measured capacitance will appear to change by approximately the capacitance between the center conductor and the shield in the coax. 14?11 a, b, c, d selector inputs these input pins control which electrode or reference is active. selection values are shown in table 1, electrode selection, page 14. 15 signal undetected signal this is the undetected signal being applied to the detector. it has a dc level with the low radio frequency signal superimposed on it. care must be taken to minimize dc loading of this signal. a shift of dc wi ll change the center point of the signal and adversely affect the detection of the signal. 16 level detected level this is the detected, amplified, and offs et representation of the signal voltage on the selected electrode. filtering of the re ctified signal is performed by a capacitor attached to lp_cap. 17 pwr_mon power monitor this is connected through a voltage divider to v pwr . it allows reduction of the voltage so it will fall within the range of the adc on the mcu. 18 lp_cap low-pass filter capacitor a capacitor on this pin forms a low pass fi lter with the internal series resistance from the detector to this pin. this pin can be used to determine the detected level before amplification or offset is applied. a 10 nf capacitor connected to this pin will smooth the rectified signal. more capacit ance will increase the response time unnecessarily. 19 r_osc oscillator resistor a resistor from this pin to circuit gr ound determines the operating frequency of the oscillator. the 33794 is optimi zed for operation around 120 khz. 24 clk clock this pin provides a square wave output at the same frequency as the internal oscillator. the edges of the square wave coincide with the peaks (positive and negative) of the sine wave. 25 v dd_ mon v dd monitor this is connected through a voltage divider to v dd . it allows reduction of the voltage so it will fall within the range of the adc on the mcu. 26 v dd v dd capacitor a capacitor is connected to this pin to fi lter the internal analog regulated supply. this supply is derived from v pwr . 27 v pwr positive power supply 12 v power applied to this pin will be converted to the regulated voltages needed to operate the part. it is also converted to 5.0 v (v cc ) and 8.5 v (v dd ) to power the mcu and external devices. 28 v cc 5.0 v regulator output this output pin requires a 47 f capacitor and provides a regulated 5.0 v for the mcu and for internal needs of the 33794. 29 agnd analog ground this pin is connected to the ground return of the analog circuitry. this ground should be kept free of transient electrical noise like that from logic switching. its path to the electrical current return point should be kept separate from the return for gnd. 30 shield shield driver this pin connects to cable shie lds to cancel cable capacitance. 32 gnd ground this pin and metal backing is the ic power return and thermal radiator/conductor. 35 test test mode control this pin is normally connec ted to circuit ground. there are special operating modes associated with this pin when it is not at ground. soicw-ep pin function description (continued) pin pin name formal name definition f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
33794 motorola analog integrated circuit device data 8 36?44 e1?e9 electrode connections these are the electrode pins. they are connec ted either directly or through coaxial cables to the electrodes for measurem ents. one of these electrodes can be selected at a time for capacitance meas urement. all of the other unselected electrodes are grounded by an internal switch. the signal at the selected electrode pin is routed to the shield driver amplifier by an internal switch. all of the coaxial cable shields should be isolated from ground and connected shield. 45, 46 ref_a, ref_b reference connections these pins can be individually selected li ke e1 through e9. unlike e1 through e9, these pins are not grounded when not select ed. the purpose of these pins is to allow known capacitors to be measured. by using capacitors at the low and high end of the expected range, absolute values for the capacitance on the electrodes can be computed. 47 iso_out iso-9141 output this pin translates iso-9141 receive levels to 5.0 v logic levels for the mcu. 51 iso_in iso-9141 input this pin accepts data from the mcu to be sent over the iso-9141 communications interface. it translates the 5.0 v logic levels from the mcu to transmit levels on the iso-9141 bus. 53 iso-9141 iso-9141 bus this pin connects to the iso-9141 bus. it provides the drive and detects signaling on the bus and translates it from the bus level to logic levels for the mcu. 54 lamp_ctrl lamp control this signal is used to control the lamp dr iver. a high logic level turns on the lamp. soicw-ep pin function description (continued) pin pin name formal name definition f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
motorola analog integrated circuit device data 33794 9 maximum ratings all voltages are with respect to ground unless otherwise noted. rating symbol value unit peak v pwr voltage v pwrpk 40 v double battery 1 minute maximum t a = 30 c v dblbat 26.5 v esd voltage human body model (note 1) machine model (note 2) v esd1 v esd2 2000 200 v storage temperature t stg -55 to 150 c operating ambient temperature t a -40 to 85 c operating junction temperature t j -40 to 150 c thermal resistance junction-to-ambient (note 3) junction-to-case (note 4) junction-to-board (note 5) r j-a r j-c r j-b 41 0.2 3.0 c/w lead soldering temperature (for 10 seconds) t solder 260 c notes 1. esd1 performed in accordance with the human body model (c zap = 100 pf, r zap = 1500 ? ). 2. esd2 performed in accordance with the machine model (c zap = 200 pf, r zap = 0 ? ). 3. junction temperature is a function of on-chip power dissipati on, package thermal resistance, mounting site (board) temperatur e, ambient temperature, air flow, power dissipation of other components on the board, and board thermal resistance. in accordance with sem i g38- 87 and jedec jesd51-2 with the single layer board horizontal. 4. indicates the average thermal resistance between the die and th e case top surface as measured by the cold plate method (milsp ec 883 method 1012.1) with the cold plate temperature used for the case temperature. 5. thermal resistance between the die and the printed circuit board per jedec jesd51-8. board temperature is measured on the top surface of the board near the package. f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
33794 motorola analog integrated circuit device data 10 static electrical characteristics characteristics noted under condition -40 c t j 150 c. voltages are relative to gnd unless otherwise noted. characteristic symbol min typ max unit voltage regulators 5.0 v regulator voltage 7.0 v v pwr 18 v, 1.0 ma i l 75 ma, c filt = 47 f v cc 4.75 5.0 5.25 v analog regulator voltage 9.0 v v pwr 18 v, c filt = 47 f v analog 8.075 8.5 8.925 v v cc out-of-range voltage detector 5.0 v low voltage detector v lv5 4.0 4.52 4.72 v 5.0 v high voltage detector v hv5 5.26 5.55 5.83 v 5.0 v out-of-range voltage detector hysteresis v hys5 ? 0.05 ? v iso-9141 communications interface input low level (note 6) vif inlo 0.30 0.33 ? v/v input high level (note 6) vif inhi ? 0.53 0.7 v/v input hysteresis (note 6) vif inhys ? 0.2 ? v/v output low (note 6) vif olo ? ? 0.2 v/v output high (note 6) vif ohi 0.8 ? ? v/v output breakdown i out = 20 ma vif z 40 ? ? v output resistance i out = 40 ma rif on ? 58 ? ? current limit sinking current with v out < 0.3 v pwr in iif lim 60 90 120 ma output propagation delay out to iso-9141, c load = 20 pf tif dly ? ? 8.0 s iso in logic output low i sink = 1.0 ma vif olo ? ? 1.0 v logic output pull-up current v out = 0 v iif pu 100 ? ? a input to output propagation delay iso-9141 to iso_in, r l = 10 k ?, c l = 470 pf, 7.0 v v pwr 18 v tif dly ? ? 5.4 s notes 6. ratio to v pwr . f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
motorola analog integrated circuit device data 33794 11 electrode signals total variance between electrode measurements (note 7) all c load = 15 pf elv var ? ? 3.0 % electrode maximum harmonic level below fundamental (note 8) 5.0 pf c load 100 pf el harm ? -20 ? db electrode transmit output range 5.0 pf c load 100 pf el txv 1.0 ? 8.0 v receive input voltage range rx v 0 ? 9.0 v grounding switch on voltage i sw = 1.0 ma sw von ? ? 5.0 v shield driver shield driver output level 0pf c load 500 pf sd txv 1.0 ? 8.0 v shield driver input range sd in 0 ? 9.0 v grounding switch on voltage (note 9) sw von ? ? 1.5 v logic i/o cmos logic input low threshold v thl 0.3 ? ? v cc logic input high threshold v thh ? ? 0.7 v cc voltage hysteresis v hys ? 0.06 ? v cc input current v in = v cc v in = 0 v i in 10 -5.0 ? ? 50 5.0 a signal detector detector output resistance det ro ? 50 ? k ? lp_cap to level gain a rec 3.6 4.0 4.4 a v lp_cap to level offset v recoff -3.3 -3.0 -2.7 v notes 7. verified by design. not tested in production. 8. verified by design and characterization. not tested in production. 9. current into grounded pin under test = 1.0 ma. static electrical charac teristics (continued) characteristics noted under condition -40 c t j 150 c. voltages are relative to gnd unless otherwise noted. characteristic symbol min typ max unit f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
33794 motorola analog integrated circuit device data 12 lamp driver on resistance i in = 400 ma rld dson ? 1.75 3.5 ? current limit v out = 1.0 v ild lim 0.7 ? 1.7 a on-voltage i out = 400 ma vld on ? ? 1.4 v breakdown voltage i out = 100 a, lamp off vld z 40 ? ? v voltage monitors lamp_mon to lamp_sense ratio lmp mon 0.1950 0.20524 0.2155 v/v pwr_mon to v pwr ratio pwr mon 0.2200 0.2444 0.2688 v/v v dd_ mon to v dd ratio v dd mon 0.45 0.5 0.55 v/v static electrical charac teristics (continued) characteristics noted under condition -40 c t j 150 c. voltages are relative to gnd unless otherwise noted. characteristic symbol min typ max unit f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
motorola analog integrated circuit device data 33794 13 dynamic electrical characteristics characteristics noted under condition -40 c t j 150 c. voltages are relative to gnd unless otherwise noted. characteristic symbol min typ max unit osc osc frequency stability (note 10), (note 11) f stab ? ? 10 % osc center frequency r_osc = 39 k ? f osc ? 120 ? khz harmonic content (note 10) 2nd through 4th harmonic level 5th and higher osch arm ? ? ? ? -20 -60 db shield driver shield driver maximum harmonic level below fundamental (note 10) 10 pf c load 500 pf sd harm ? -20 ? db shield driver gain bandwidth product (note 10) measured at 120 khz sd gbw ?4.5 ? mhz por por time-out period t per 9.0 ? 50 ms watchdog watchdog time-out period t wdper 50 68 250 ms watchdog reset hold time t wdhld 9.0 ? 50 ms lamp driver short circuit to batte ry survival time t scb 3.0 ? ? ms notes 10. verified by design and characterization. not tested in production. 11. does not include errors in external reference parts. f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
33794 motorola analog integrated circuit device data 14 table 1. electrode selection pin/signal d c b a source (internal) 0 0 0 0 e1 0 0 0 1 e2 0 0 1 0 e3 0 0 1 1 e4 0 1 0 0 e5 0 1 0 1 e6 0 1 1 0 e7 0 1 1 1 e8 1 0 0 0 e9 1 0 0 1 ref_a 1 0 1 0 ref_b 1 0 1 1 internal osc 1 1 0 0 internal osc after 22 k ? 1 1 0 1 internal ground 1 1 1 0 reserved 1 1 1 1 f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
motorola analog integrated circuit device data 33794 15 system/application information introduction the 33794 is intended for use in detecting objects using an electric field. the ic generates a low radio frequency sine wave. the frequency is set by an external resistor and is optimized for 120 khz. the sine wave has very low harmonic content to reduce potential inte rference at higher harmonically related frequencies. the internal generator produces a nominal 5.0 v peak-to-peak output that is passed through an internal resistor of about 22 k ? . an internal multiplexer routes the signal to one of 11 pins under control of the abcd input pins. a receiver multiplexer si multaneously connected to the selected electrode routes its signal to a detector, which converts the sine wave to a dc level. this dc level is filtered by an external capacitor and is multiplied and offset to increase sensitivity. all of the unse lected electrode outputs are grounded by the device. the current flowing between the selected electrode and the other grounded electrodes plus other grounded objects around the electrode causes a voltage drop across the internal resistanc e. objects brought into or out of the electric field change the current and resulting voltage at the ic pin, which in turn reduces the voltage at lp_cap and level. a shield driver is included to minimize the effect of capacitance caused by using co axial cables to connect to remote electrodes. by driving t he coax shield with this signal, the shield voltage follows that of the center conductor, significantly reducing the effectiv e capacitance of the coax and maintaining sensitivity to the capacitance at the electrode. the 33794 is made to work with and support a microcontroller. it provides two voltage regulators, a power- on-reset/out-of-range voltage detector, watchdog circuit, lamp driver and sense circuit, and a physical layer iso-9141 communications interface. block diagram components refer to figure 1 , 33794 internal block diagram, page 2, for a graphic representation of the block diagram information in this section. osc this section generates a high purity sine wave. the center frequency is controlled by a resistor attached to r_osc. the normal operating frequency is around 120 khz. a square wave version of the frequency output is available at clk. timing for the power-on reset and watchdog (por/wd) circuit are derived from this oscillator?s frequency. mux out this circuit directs the output of the sine wave to one of nine possible electrode outputs or two reference pins. all unused pins are automatically grounded. the selected output is controlled by the abcd inputs. mux in this circuit connects the selected electrode, reference, or one of two internal nodes to an amplifier/detector. the selection is controlled by the abcd inputs and follows the driven electrode/reference when one is selected. rect the rectifier circuit detects the level from mux in by offsetting the midpoint of th e sine wave to zero volts and inverting the waveform when it is below the midpoint. it is important to avoid dc loading of the signal, which would cause a shift in the midpoint voltage of the signal from the mux in. lpf the rectified sine wave is filter ed by a low pass function in the lpf formed by an internal resistance and an external capacitance attached to lp_cap. the nominal value of the internal resistance is 50 k ? . the value of the external capacitor is selected to provide filtering of noise while still allowing the desired settling time for the detector output. a 10 nf capacitor would allow 99% settling in less than 5.0 ms. gain and offset this circuit multiplies the det ected and filtered signal by a gain and offsets the result by a dc level. this results in an output range that covers 1.0 v to 4.0 v for capacitive loading of the field in the range of 10 pf to 100 pf. this allows higher sensitivity for a digital-to-ana log converter with a 0 v-to-5.0 v input range. attn this circuit passes the undetec ted signal to signal for external use. lamp ckt this section controls the operation of the lamp_out pin. when lamp_ctrl is asserted, lamp_out is pulled to lamp_gnd. if one side of an indicator lamp or led (with appropriate current setting resisto r) is connected to a positive voltage source and the other is connected to lamp_out, and lamp_gnd is connected to ground, the lamp will light. this circuit provides current limiting to prevent damage to itself in the case of a shorted lamp or during a high-surge condition typical of an incandescent lamp burnout. f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
33794 motorola analog integrated circuit device data 16 iso-9141 this circuit connects to an iso-9141 bus to allow remote communications. iso_in is data from the bus to the mcu and iso_out is data to drive onto the bus from the mcu. por/wd this circuit is a combined power-on reset and watchdog timer. the rst output is held low until a certain amount of time after the v cc output has remained above a minimum operating threshold. if v cc falls below the level at any time, rst is pulled low again and held until the required time after v cc has returned high. an overvoltage circuit is also included, which will force a reset if v cc rises above a maximum voltage. the watchdog function also can force rst low if too long an interval is allowed to pass between positive transitions on wd_in. v cc reg this circuit converts an unregulated voltage from vin to a regulated 5.0 v source, which is used internally and available for other components requiring a regulated voltage source. v dd reg this is a regulator for analog devices that require more than 5.0 v. this is used by the device and some current is available to operate op-amps and other devices. by having this higher voltage available, some applications can avoid the need for a rail-to-rail output amplifier and still achieve the 0 v-to-5.0 v output for a digital-to-analog converter input. v ddmon is a divided output from v dd , which allows a 0 v-to-5.0 v adc to measure v dd . control logic this contains the logic that decodes and controls the muxes and some of the test modes. application information the 33794 is intended to be used where an object?s size and proximity are to be determined. this is done by placing electrodes in the area where the object will be. the proximity of an object to an electrode can be determined by the increase in effective capacitance as the objec t gets closer to the electrode and modifies the electric field between the electrode and surrounding electrically common objects. the shape and size of an object can be determined by us ing multiple electrodes over an area and observing the capacit ance change on each of the electrodes. those that don?t c hange have nothing near them, and those that do change have part of the object near them. the voltage measured is an in verse function of the capacitance between the electrode being measured and the surrounding electrodes and other objects in the electric field surrounding the electrode. increasing capacitance results in decreasing voltage. the value of series resistance (22 k ? ) was chosen to provide a nearly linear relationship at 120 khz over a range of 10 pf to 100 pf. the measured value will change with any change in frequency, series resistance, driving voltage, or detector sensitivity. these can change with temperature and time. the proper use of ref_a and ref_b will allow much of the changes to be compensated for. a typical measurement algorithm would start by measuring the voltage for two known value capacitors (attached to ref_a and ref_b). the value of these capacitors would be chosen to be near the minimum and maximum values of capacitance expected to be seen at the electrodes. these reference voltages and the known capacit ance values are then used with the electrode measurement voltage to determine the capacitance seen by the electrode. this method can be used to detect short- and long-term changes due to objects in the electric field and significantly reduce the effect of temperature- and time-induced changes. the 33794 does not contain an adc. it is intended to be used with an mcu that contains one. offset and gain have been added to the 33794 to maximize the sensitivity over the range of 0 pf to 100 pf. an 8-bit adc can resolve around 0.4 pf of change and a 10-bit converter around 0.1 pf. higher resolution results in more distant detection of smaller objects. dc loading on the electrodes should be avoided. the signal is generated with a dc offset that is more than half the peak-to- peak level. this keeps the signal positive above ground at all times. the detector uses this voltage level as the midpoint for detection. all signals below this level are inverted and added to all signals above this level. loading of the dc level will cause some of the positive half of the signal to be inverted and added and will change the measurement. if it is not possible to assure that the electrodes will always have a high dc resistance to ground or a voltage source, a series capacitor of about 10 nf should be connected between the ic electrode pins and the electrodes. f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
motorola analog integrated circuit device data 33794 17 figure 2. typical application diagram v dd lamp_out v cc lp_cap 33794 v pwr v cc iso-9141 signal ref_a ref_b e1 e2 e9 shield level v dd_ mon pwr_mon lamp_mon lamp_sense iso_in iso_out wd_in rst lamp_ctrl lamp_gnd test a, b, c, d dis_shield r_osc agnd gnd analog_in analog_in analog_in analog_in analog_in iso_tx iso_rx watchdog reset electrode select shield disable 39 k ? 100 pf 10 pf 10 k ? 47 f 0.1 f 47 f 10 nf indicator lamp monitor (optional) +12 v 1 9 2 gpx mcu iso-9141 bus field electrodes 4 f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
33794 motorola analog integrated circuit device data 18 package dimensions seating plane datum plane bottom view a x 45 e1 e d h e 42x b m bbb c 44 23 22 1 e2 d2 d1 e3 a2 section w-w b c1 b1 c e4 a m aaa c exposed heatsink area a b c h pin one id 22x y gauge plane detail y (1.600) l w w q bbb c l1 a1 0.325 notes: 1. controlling dimension: millimeter. 2. dimensions and tolerances per asme y14.5m, 1994. 3. datum plane -h- is located at bottom of lead and is coincident with the lead where the lead exits the plastic body at the bottom of the parting line. 4. dimensions d and e1 do not include mold protrusion. allowable protrusion is 0.150 per side. dimensions d and e1 do include mold mismatch and are determined at datum plane -h-. 5. dimension b does not include dambar protrusion. allowable dambar protrusion shall be 0.127 total in excess of the b dimension at maximum material condition. 6. datums -a- and -b- to be determined at datum plane -h-. 7. dimension d does not include tiebar protrusions. allowable tiebar protrusions are 0.150 per side. dim min max millimeters a 3.000 3.400 a1 0.025 0.125 a2 2.900 3.100 d 15.800 16.000 d1 11.700 12.600 d2 0.900 1.100 e 13.950 14.450 e1 10.900 11.100 e2 2.500 2.700 e3 6.400 7.300 e4 2.700 2.900 l 0.840 1.100 l1 0.350 bsc b 0.220 0.350 b1 0.220 0.320 c 0.230 0.320 c1 0.230 0.280 e 0.650 bsc h --- 0.800 q 0 8 aaa 0.200 bbb 0.100 e5 --- 1.000 d3 --- 1.000 d3 4x e5 4x dh suffix 44-lead hsop plastic package case 1291-01 issue o f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
motorola analog integrated circuit device data 33794 19 dwb suffix 54-lead soicw-ep case 1390-01 issue b notes: 1. all dimensions are in millimeters. 2. dimensioning and to lerancing 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 no t 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 0.46 mm. 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 0.1 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 17.8 7.4 1 27 28 54 0.10 a 2.35 seating plane 0.9 section b-b 0.65 r0.08 min b a (0.29) 0.38 0.30 (0.25) plating base metal section a-a rotated 90 clockwise 8 0.25 0.22 9 5 0.13 m c ab 6 a c 7.6 18.0 9 4 10.3 5.15 a 54x 52x 2.65 0.3 a 2x 27 tips b c bb 0.1 0.0 0.5 0 8 0 0.25 gauge plane min pin 1 index c c (1.43) 4.8 4.3 0.30 c ab 4.8 4.3 0.30 c ab view c-c plastic package f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .
how to reach us: usa/europe/locations not listed: japan: motorola japan ltd.; sps, technical information center motorola literature distribution 3-20-1 minami-azabu. minato-ku, tokyo 106-8573, japan p.o. box 5405, denver, colorado 80217 81-3-3440-3569 1-800-521-6274 or 480-768-2130 asia/pacific: motorola semiconductors h. k. ltd.; silicon harbour centre 2 dai king street, tai po industrial estate, tai po, n.t., hong kong 852-26668334 home page: http://motorola.com/semiconductors MC33794/d information in this document is provided solely to enable system and software implem enters to use motorola products. there are no express or implied copyright licenses granted hereunder to desig n or fabricate any integrated circuits or integrated circuits based on the informa tion in this document. motorola reserves the right to make changes without further noti ce to any products herein. motorola makes no warranty, represen tation or guarantee regarding the suitability of its products for any particular purpose, nor does motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. ?typical? parameters which may be provided in motorola data sheets and/or s pecifications can and do vary in different applications and actual performance may var y over time. all operating parameters, including ?typicals? must be validated for each customer application by customer?s technical experts. motorola does not convey any license under its patent rights nor the rights of others. motorola pro ducts are not designed, intended, or authorized for use as compon ents in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in whic h the failure of the motorola product could create a situation where personal injury or death may occur. should buyer purchase or use motorola products for any such unintended or unauthorized application, buyer shall indemnify and hold motorola and its officers, employees, subsidiaries, affiliates, and di stributors harmless against all claims, costs, damages, and expenses , and reasonable attorney fees arising out of, directly or indirectly, any claim of persona l injury or death associated with such unintended or unauthorized use, even if such claim a lleges that motorola was negligent regarding the design or manufa cture of the part. motorola and the stylized m logo are registered in the us patent and trademark office. all other product or service names are t he property of their respective owners. ? motorola, inc. 2004 f r e e s c a l e s e m i c o n d u c t o r , i freescale semiconductor, inc. f o r m o r e i n f o r m a t i o n o n t h i s p r o d u c t , g o t o : w w w . f r e e s c a l e . c o m n c . . .

▲Up To Search▲

Price & Availability of MC33794

	To Download MC33794 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .