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differential two-wire hall effect sensor ic TLE4942 TLE4942c features two-wire pwm current interface detection of rotation direction airgap diagnosis assembly position diagnosis dynamic self-calibration principle single chip solution no external components needed high sensitivity psso2-1 south and north pole pre-induction possible high resistance to piezo effects large operating air-gaps wide operating temperature range TLE4942c: 1.8nf overmolded capacitor type marking ordering code package tle 4942 4200e4 q62705-k428 psso2-1 tle 4942c 42c0e4 q62705-k437 psso2-2
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 2 the hall effect sensor ic TLE4942 is designed to provide information about rotational speed , direction of rotation , assembly position and limit airgap to modern vehicle dynamics control systems and abs. the output has been designed as a two wire current interface based on a pulse width modulation principle. the sensor operates without external components and combines a fast power-up time with a low cut-off frequency. excellent accuracy and sensitivity is specified for harsh automotive requirements as a wide temperature range , high esd robustness and high emc resilience. s tate-of-the-art bicmos technology is used for monolithic integration of the active sensor areas and the signal conditioning. finally, the optimised piezo compensation and the integrated dynamic offset compensation enable easy manufacturing and elimination of magnet offsets. the TLE4942c is additionally provided with an overmolded 1.8nf capacitor for improved emi performance.
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 3 functional description the differential hall effect ic detects the motion of ferromagnetic or permanent magnet structures by measuring the differential flux density of the magnetic field. to detect the motion of ferromagnetic objects the magnetic field must be provided by a backbiasing permanent magnet. either the south or north pole of the ma g net can be attached to the rear, unmarked side of the ic package. magnetic offsets of up to 20mt and mechanical offsets are cancelled out through a self-calibration algorithm. only a few transitions are necessary for the self-calibration procedure. after the initial self-calibration sequence switching occurs when the input signal crosses the arithmetic mean of its max. and min. values (e.g. zero-crossing for sinusoidal si g nals). the on and off state of the ic are indicated by high and low current consumption. each zero crossing of the magnetic input signal triggers an output pulse. i figure 3 zero-crossing principle and corre sponding output pulses differential magnetic flux density d b t range for el pulse: d b el range for warning pulse: d b warning d b limit (max . airgap exceeded) figure 4 definition of differential magnetic flux density ranges magnetic signal output signal pulse length
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 4 pin configuration (view on branded side of component) figure 1 right left center pga offset dac main comp digital gain range power supply regulator oscillator "x" "x"= (left + right)/2 - center "vcc" "signal" - - hall probes: speed adc direction adc adc circuit (syst clock) figure 2 bloc k diagram s 0015 4942 date code marking center of sensitive area 0.15 gnd v cc s 0015 4200e4 2.5 v cc gnd 1.44 2.67
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 5 in addition to the speed signal, the following information is provided by varying the length of the output pulses in figure 3 (pwm modulation): airgap warning range = warning warning information is issued in the output pulse length when the magnetic field is below a critical value. (e. g. the airgap between the hall effect ic and the target wheel exceeds a critical value). the device works with reduced functionality. assembly position range = el el information is issued in the output pulse length when the magnetic field is below a predefined value (the airgap between the hall effect ic and the target wheel e x ceeds a predefined value). the device works with full functionality. direction of rotation right = dr - r dr?r information is issued in the output pulse length when the target wheel in front of the hall effect ic moves from the pin gnd to the pin v cc . direction of rotation left = dr - l dr?l information is issued in the output pulse length when the target wheel in front of the hall effect ic moves from the pin v cc to the pin gnd. figure 5 definition of rotation direction s 0015 4942 dr-l dr-r
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 6 circuit description the circuit is supplied internally by a voltage regulator. an on-chip oscillator serves as a clock ge n erator for the dsp and the output encoder. speed signal circuitry: TLE4942 speed signal path comprises of a pair of hall effect probes, separated from each other by 2.5mm, a differential a m plifier including noise limiting low-pass filter, and a comparator triggering a switched current output stage. an offset cancellation feedback loop is provided through a signal-tracking a/d converter, a digital signal processor (dsp), and an offset cancellation d/a co n verter. during the power-up phase ( uncalibrated mode) the output is disabled. the differential input signal is digitized in the speed a/d converter and fed into the dsp part of the ci r cuit. the minimum and maximum values of the input signal are extracted and their corresponding arithmetic mean value is calculated. the offset of this mean value is determined and fed into the offset cancellation dac. after successful correction of the offset, the output switching is enabled. in running mode (calibrated mode) the offset correction algorithm of the dsp is switched into a low-jitter mode, thereby avoiding oscillation of the offset dac lsb. switching occurs at zero-crossover. it is only affected by the small residual offset of the comparator and by the propagation delay time of the signal path, which is mainly determined by the noise limiting filter. signals which are below a predefined threshold d b limit are not detected. this prevents unwanted switching. the comparator also detects whether the signal amplitude exceeds d b warning or d b el . this information is fed into the dsp and the output encoder. the pulse length of the high output current is generated according to the rotational speed, the direction of rotation and the magnetic field strength. direction signal circuitry: the differential signal between a third hall probe and the mean of the differential hall probe pair is obtained from the direction input amplifier. this signal is digitized by the direction adc and fed into the dsp circuitry. there, the phase of the signal referring to the speed signal is analyzed and the direction info r mation is forwarded to the output encoder.
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 7 absolute maximum ratings t j = -40 to 150c, 4.5v v cc 16.5v limit values unit remarks parameter symbol min max supply voltage v cc -0.3 t j < 80c supply voltage v cc 16.5 v t j = 170c supply voltage v cc 20 v t j = 150c supply voltage v cc 22 v t = 10 * 5 min supply voltage v cc 24 v t = 10 * 5 min, r m 3 75 w supply voltage v cc 27 v t = 400 ms, r m 3 75 w reverse polarity current i rev 200 ma external current limit a tion required, t < 4h junction temperature junction temperature junction temperature junction temperature t j t j t j t j 150 160 170 190 c c c c 5000 h, v cc < 16.5v 2500 h, v cc < 16.5v 500 h, v cc < 16.5v 4 h, v cc < 16.5v active lifetime t b,active 10000 h storage temperature t s -40 150 c thermal resistance psso2-1 r thja 190 k/w 1) esd u esd 2 kv according to standard eia/jesd22-a114-b hbm 2) r=1500 w , c=100pf 1) can be improved significantly by further processing like overmolding 2) covers mil std 883d note: stresses in excess of those listed here may cause permanent damage to the device. exposure to absolute maximum rating conditions for extended periods may affect device reliability.
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 8 operating range limit values unit remarks parameter symbol min max supply voltage v cc 4.5 20 v supply voltage ripple v ac 6 v pp v cc =13v 0 < f < 50khz junction temperature t j -40 150 c junction temperature t j 170 c v cc 16.5v, increased jitter permissible pre-induction b 0 -500 +500 mt pre-induction offset between outer probes d b stat ., l/r -20 +20 mt pre-induction offset between mean of outer probes and center probe d b stat ., m/o -20 +20 mt differential induction d b -120 +120 mt note: within the operating range the functions given in the circuit description are fulfilled.
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 9 ac/dc characteristics all values specified at constant amplitude and offset of input signal limit values unit parameter symbol min typ max remarks supply current i low 5.9 7 8.4 ma supply current i high 11.8 14 16.8 ma supply current ratio i high / i low 1.9 output rise/fall slew rate TLE4942 t r , t f 12 7.5 26 24 ma/ m s r m 150 w r m 750 w see figure 6. output rise/fall slew rate TLE4942c t r , t f 8 8 22 26 ma/ m s r m = 75 w t < 125c t < 170c see figure 6. current ripple di x / dv cc i x 90 a/v limit threshold d b limit 0.35 0.8 1.5 mt amplitude values airgap warning threshold d b warning 0.9 1.4 2.6 mt amplitude values limit - airgap warning threshold ratio d b warning / d b limit 1.3 1.75 2.7 amplitude values assembly position threshold d b el 5.2 7.2 9.6 mt at room temp
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 10 initial calibration delay time t d,input 300 s additional to n start magnetic edges required for initial calibration 1) n start 6 * magn. edges number of emitted pulses with invalid supplementary information 2) n dr -start 3 * magn. edges frequency f 1 2500 hz frequency changes df/ dt 100 hz/ms duty cycle duty 40 50 60 % 3) measured @ d b = 2mt sine wave def. figure 7 jitter, t j < 150c t j < 170c s jit -close 2 3 % % 1 s value v cc = 12 v ?b 3 2mt jitter, t j < 150c t j < 170c s jit -far 4 6 % % 1 s value v cc = 12 v (2mt 3 ) d b > d b limit jitter at board net ripple s jit -ac 2 % v cc =13v6v pp 0 < f < 50khz d b = 15 mt * see appendix b 1) the sensor requires up to n start magnetic switching edges for valid speed information after power-up or after a stand still condition. during that phase the output is disabled. 2) the first 3 pulses containing direction information can have the wrong rotation information. (the first pulse after starting with the speed signal can have any length < t stop . at d blimit output pulses might have any length < t stop ). 3) during fast offset alterations, due to the calibration algorithm, exceeding the specified duty cycle is permitted for short time periods.
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 11 tr tf i i high i low t 90% 50% 10% t1 figure 6 definition of rise and fall time timing characteristics limit values unit parameter symbol min typ max remarks pre-low length t pre -low 38 45 52 s length of warning pulse t warning 38 45 52 s length of dr-l pulse t dr -l 76 90 104 s length of dr-r pulse t dr -r 153 180 207 s length of dr-l & el pulse t dr -l&el 306 360 414 s length of dr-r & el pulse t dr -r&el 616 720 828 s output of el pulse, maximum fr e quency f el, max 117 hz length of stand still pulse t stop 1.232 1.44 1.656 ms def. fig.9 stand still period 1) t stop 590 737 848 ms def. fig. 9 1) if no magnetic switching edge is detected for a period longer than t stop , the stand still pulse is issued.
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 12 t i i high i low t t 1 xn xn xn+1 xn+2 duty = t1 / t * 100% figure 7 definition of duty cycle pwm current interface between each magnetic transition and the rising edge of the corresponding output pulse the output current is low for t pre -low in order to allow reliable internal conveyance. following the signal pulse (current is high ) is output. if the magnetic differential field exceeds d b el , the output pulse lengths are 90s or 180s respectively, depending on the dire c tion of rotation. when the magnitude of the magnetic differential field is below d b el , the output pulse lengths are 360s and 720s respectively, depending on left or right rotation. due to decreasing cycle times at higher frequencies, these longer pulses are only output up to frequencies of approximately 117hz. for higher frequencies and differential magnetic fields below d b el , the output pulse lengths are 90 s or 180s respectively. if the magnitude of the magnetic differential field is below d b warning , the output pulse length is 45s. the warning output is dominant, this means that close to the limit airgap the direction and the assembly position information are disabled. for magnitudes of the magnetic differential field below d b limit , signal is lost. in case no magnetic differential signal is detected for a time longer than the stand still period t stop , the stop pulse is output. typically with the first output stop pulse, the circuitry reverts to the uncalibrated mode.
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 13 internal sensor speed signal transferred signal : lr transferred signal : dr-l transferred signal: dr-r transferred signal: dr-l & el transferred signal: dr-r & el t pre-low = 45s t lr = 45s . t dr-l = 2 * t lr t dr- r = 4 * t lr t dr-l&ap = 8 * t lr t dr-r&ap = 16 * t lr xn xn+1 xn+2 x n x n+1 x n+2 figure 8 definition of pwm current interface internal sensor speed signal transferred signal: stand still t stop t stop = 32 * t lr figure 9 definition of stand still output pulse
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 14 duty cycle at fast changing frequencies if the duty cycle deviates from 50%, it is possible that the present pulse length is output entirely once and cut once, within the same period, see figure 10. internal sensor speed signal at increasing speed transferred signal pulse lengths are shorter than half speed period length pulse lengths are longer than half speed period length figure 10 deviation of duty cycle at fast changing frequencies
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 15 electro magnetic compatibility - (values depend on r m !) ref. iso 7637-1; test circuit 1; d b = 2mt (amplitude of sinus signal); v cc =13.5 v, f b = 100 hz; t= 25c; r m 3 75 w no. parameter symbol level/ typ. status 1.1.1 testpulse 1 testpulse 2 testpulse 3a testpulse 3b testpulse 4 testpulse 5 v ld iv / -100 v iv / 100 v iv / -150 v iv / +100 v iv / -7 v iv / +86,5 v (2) c (1) c (1) a a b (3) c (1) according to 7637-1 the supply switched ?off? for t=200ms. for battery ?on? is valid status ?a?. (2) applying in the board net a suppressor diode with sufficient energy absorption capability. (3) according to 7637-1 for test pulse 4 the test voltage shall be 12v 0,2v values are valid for all tle4941/42 types! ref. iso 7637-3; test circuit 1; d b = 2mt (amplitude of sinus signal); v cc =13.5 v, f b = 100 hz; t= 25c; r m 3 75 w no. parameter symbol level/ typ. status 1.2.1 testpulse 1 testpulse 2 testpulse 3a testpulse 3b v ld iv / -30 v iv / 30 v iv / -60 v iv / 40 v a a a a values are valid for all tle4941/42 types! ref. iso 11452-3; test circuit 1; measured in tem-cell d b = 2mt; v cc =13.5v, f b = 100 hz; t= 25c no. parameter symbol level/max. remarks 1.2.2 emc field strength e tem-cell iv / 200 v/m am=80%, f=1khz; only valid for non c- types! ref. iso 11452-3; test circuit 1; measured in tem-cell d b = 2mt; v cc =13.5v, f b = 100 hz; t= 25c no. parameter symbol level/max. remarks 1.2.2 emc field strength e tem-cell iv / 250 v/m am=80%, f=1khz; only valid for c-types!
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 16 figure 11 test circuit 1 v emc d 1 d 2 c 1 r m c 2 v cc gnd components: d1: 1n4007 d2: t 5z27 1j c1: 10 f/35v c2: 1nf/1000v rm: 75 w /5w emc- generator mainfra me sensor
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 17 package outlines psso2-1 (plastic single small outline package)
TLE4942, TLE4942c TLE4942 - TLE4942c data sheet february 2002 18 psso2-2 ( plastic single small outline package )

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