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 • 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 PSSO2-1 Type Marking Ordering Code Package TLE 4942 4200E4 Q62705-K428 PSSO2-1 TLE 4942C 42C0E4 Q62705-K437 PSSO2-2 TLE4942, TLE4942C 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. State-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 Data Sheet 2 February 2002 TLE4942, TLE4942C 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 magnet 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 signals). 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. Magnetic signal Pulse length Output Signal I Figure 3 Zero-crossing principle and corresponding output pulses Differential Magnetic Flux Density ∆B Range for EL pulse: ∆BEL Range for warning pulse: ∆BWarning ∆BLimit (max .airgap exceeded) t Figure 4 Definition of differential magnetic flux density ranges TLE4942 - TLE4942C Data Sheet 3 February 2002 TLE4942, TLE4942C Pin Configuration (view on branded side of component) 2.67 S 0015 S 0015 4942 4200E4 Date Code 1.44 Marking 2.5 Center of sensitive area ±0.15 VCC VCC GND GND Figure 1 "Vcc" power supply regulator main comp "signal" oscillator hall probes: right (syst clock) - - speed ADC PGA offset DAC digital gain range circuit center direction ADC "x" left Figure 2 "x"= (left + right)/2 - center Block diagram TLE4942 - TLE4942C Data Sheet 4 February 2002 TLE4942, TLE4942C 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 exceeds 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 VCC. 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 VCC to the pin GND. DR-L DR-R S 0015 4942 Figure 5 Definition of rotation direction TLE4942 - TLE4942C Data Sheet 5 February 2002 TLE4942, TLE4942C Circuit Description The circuit is supplied internally by a voltage regulator. An on-chip oscillator serves as a clock generator 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 amplifier 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 converter. 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 circuit. 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 ∆BLimit are not detected. This prevents unwanted switching. The comparator also detects whether the signal amplitude exceeds ∆BWarning or ∆BEL. 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 information is forwarded to the output encoder. TLE4942 - TLE4942C Data Sheet 6 February 2002 TLE4942, TLE4942C Absolute Maximum Ratings Tj = -40 to 150°C, 4.5V ≤ Vcc ≤ 16.5V Parameter Supply voltage Supply voltage Supply voltage Supply voltage Supply voltage Supply voltage Reverse polarity current Junction temperature Junction temperature Junction temperature Junction temperature Active lifetime Storage Temperature Thermal Resistance PSSO2-1 ESD Vcc Vcc Vcc Vcc Vcc Vcc Irev Limit values Min Max -0.3 16.5 20 22 24 27 200 Tj Tj Tj Tj 150 160 170 190 Symbol tB,active Ts RthJA 10000 -40 UESD Unit Remarks V V V V V mA 150 190 °C °C °C °C h °C K/W ±2 kV Tj < 80°C Tj = 170°C Tj = 150°C t = 10 * 5 min t = 10 * 5 min, RM≥75Ω t = 400 ms, RM≥75Ω External current limitation required, t < 4h 5000 h, Vcc < 16.5V 2500 h, Vcc < 16.5V 500 h, Vcc < 16.5V 4 h, Vcc < 16.5V 1) According to standard EIA/JESD22-A114-B HBM 2) R=1500 Ω, 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 Data Sheet 7 February 2002 TLE4942, TLE4942C Operating Range Parameter Symbol Limit values Min Max 4.5 20 6 Supply voltage Supply voltage ripple VCC VAC Junction temperature Junction temperature Tj Tj -40 Pre-induction Pre-induction offset between outer probes Pre-induction offset between mean of outer probes and center probe Differential Induction B0 ∆Bstat., l/r Unit V Vpp 150 170 °C °C -500 -20 +500 +20 mT mT ∆Bstat., m/o -20 +20 mT ∆B -120 +120 mT Remarks VCC=13V 0 < f < 50kHz VCC ≤ 16.5V, increased jitter permissible Note: Within the operating range the functions given in the circuit description are fulfilled. TLE4942 - TLE4942C Data Sheet 8 February 2002 TLE4942, TLE4942C AC/DC Characteristics All values specified at constant amplitude and offset of input signal Parameter Supply current Supply current Supply current ratio Output rise/fall slew rate TLE4942 Output rise/fall slew rate TLE4942C Symbol ILow IHigh IHigh/ILow tr, tf Unit mA/µs RM ≤ 150 Ω mA/µs RM ≤ 750 Ω See Figure 6. RM = 75 Ω T < 125°C 24 8 22 8 26 0.35 0.8 90 1.5 µA/V mT ∆BWarning 0.9 1.4 2.6 mT ∆BWarning / ∆BLimit ∆BEL 1.3 1.75 2.7 5.2 7.2 9.6 tr, tf TLE4942 - TLE4942C Data Sheet 9 Remarks mA mA 7.5 Current ripple dIX/dVCC IX Limit threshold ∆BLimit Airgap warning threshold Limit - Airgap warning threshold ratio Assembly position threshold Limit values Min Typ Max 5.9 7 8.4 11.8 14 16.8 1.9 12 26 T < 170°C See Figure 6. mT Amplitude values Amplitude values Amplitude values at room temp February 2002 TLE4942, TLE4942C Initial calibration delay time Magnetic edges required for initial calibration1) Number of emitted pulses with invalid supplementary information 2) Frequency Frequency changes Duty cycle t d,input 300 µs nstart 6* magn. edges nDR-Start 3* magn. edges 2500 ±100 60 Hz Hz/ms % Jitter, Tj < 150°C SJit-close ±2 % ±3 % ±4 % ±6 % ±2 % f df/dt duty 1 40 50 Tj < 170°C Jitter, Tj < 150°C SJit-far Tj < 170°C Jitter at board net ripple SJit-AC Additional to nstart 3) Measured @∆B = 2mT sine wave Def. Figure 7 1 s value VCC = 12 V ?B ≥ 2mT 1 s value VCC = 12 V (2mT ≥) ∆B > ∆BLimit VCC=13V±6Vpp 0 < f < 50kHz ∆B = 15 mT * See Appendix B 1) The sensor requires up to nstart 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 < tStop. At ∆BLimit output pulses might have any length < tStop). 3) During fast offset alterations, due to the calibration algorithm, exceeding the specified duty cycle is permitted for short time periods. TLE4942 - TLE4942C Data Sheet 10 February 2002 TLE4942, TLE4942C I tr tf IHigh 90% 50% 10% ILow t1 t Figure 6 Definition of rise and fall time Timing Characteristics Parameter Symbol Pre-low length Length of Warning pulse Length of DR-L pulse Length of DR-R pulse Length of DR-L & EL pulse Length of DR-R & EL pulse Output of EL pulse, maximum frequency Length of stand still pulse Stand still period 1) tpre-low tWarning tDR-L tDR-R tDR-L&EL Limit values Min Typ Max 38 45 52 38 45 52 76 90 104 153 180 207 306 360 414 tDR-R&EL 616 f EL, max tstop Tstop 720 828 117 1.232 590 1.44 737 Unit Remarks µs µs µs µs µs µs Hz 1.656 848 ms ms Def. Fig.9 Def. Fig. 9 1) If no magnetic switching edge is detected for a period longer than Tstop, the stand still pulse is issued. TLE4942 - TLE4942C Data Sheet 11 February 2002 TLE4942, TLE4942C I IHigh Xn Xn+1 Xn+2 ILow t1 T t 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 tpre-low in order to allow reliable internal conveyance. Following the signal pulse (current is High) is output. If the magnetic differential field exceeds ∆BEL, the output pulse lengths are 90µs or 180µs respectively, depending on the direction of rotation. When the magnitude of the magnetic differential field is below ∆BEL, the output pulse lengths are 360µs and 720µs 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 ∆BEL, the output pulse lengths are 90µs or 180µs respectively. If the magnitude of the magnetic differential field is below ∆BWarning, the output pulse length is 45µs. 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 ∆BLimit, signal is lost. In case no magnetic differential signal is detected for a time longer than the stand still period Tstop, the stop pulse is output. Typically with the first output stop pulse, the circuitry reverts to the uncalibrated mode. TLE4942 - TLE4942C Data Sheet 12 February 2002 TLE4942, TLE4942C Internal sensor speed signal tpre-low = 45µs Transferred signal : LR Xn Xn+1 Xn+2 tLR = 45µs. Transferred signal : DR-L tDR-L = 2 ∗ tLR Transferred signal: DR-R tDR-R = 4 ∗ tLR Transferred signal: DR-L & EL tDR-L&AP = 8 ∗ tLR Transferred signal: DR-R & EL Xn Figure 8 Xn+1 tDR-R&AP = 16 ∗ tLR Xn+2 Definition of PWM current interface Internal sensor speed signal tstop = 32 ∗ tLR Transferred signal: Stand still Tstop Figure 9 Definition of stand still output pulse TLE4942 - TLE4942C Data Sheet 13 February 2002 TLE4942, TLE4942C 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 Figure 10 Pulse lengths are longer than half speed period length Deviation of duty cycle at fast changing frequencies TLE4942 - TLE4942C Data Sheet 14 February 2002 TLE4942, TLE4942C Electro Magnetic Compatibility - (values depend on RM!) Ref. ISO 7637-1; test circuit 1; ∆B = 2mT (amplitude of sinus signal); VCC=13.5 V, fB= 100 Hz; T= 25°C; RM ≥ 75 Ω No. Parameter 1.1.1 Testpulse 1 Status Symbol Level/typ. VLD IV / -100 V C (1) Testpulse 2 IV / 100 V C (1) Testpulse 3a IV / -150 V A Testpulse 3b IV / +100 V A Testpulse 4 IV / -7 V (3) B (2) C IV / +86,5 V Testpulse 5 (1) According to 7637-1 the supply switched „OFF“ for t=200ms. For battery „ON“ is valid status „A“. 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 (2) Values are valid for all TLE4941/42 types! Ref. ISO 7637-3; test circuit 1; ∆B = 2mT (amplitude of sinus signal); VCC=13.5 V, fB= 100 Hz; T= 25°C; RM ≥ 75 Ω No. Parameter Symbol Level/typ. Status 1.2.1 Testpulse 1 VLD IV / -30 V A Testpulse 2 IV / 30 V A Testpulse 3a IV / -60 V A Testpulse 3b IV / 40 V A Values are valid for all TLE4941/42 types! Ref. ISO 11452-3; test circuit 1; measured in TEM-cell ∆B = 2mT; VCC=13.5V, fB= 100 Hz; T= 25°C No. Parameter 1.2.2 EMC field strength Symbol Level/Max. ETEM-Cell IV / 200 V/m Remarks AM=80%, f=1kHz; Only valid for non C- types! Ref. ISO 11452-3; test circuit 1; measured in TEM-cell ∆B = 2mT; VCC=13.5V, fB= 100 Hz; T= 25°C Symbol No. Parameter 1.2.2 EMC field strength ETEM-Cell Level/Max. IV / 250 V/m Remarks AM=80%, f=1kHz; Only valid for C-types! TLE4942 - TLE4942C Data Sheet 15 February 2002 TLE4942, TLE4942C D1 VCC Sensor GND D2 VEMC C1 RM EMC- Generator Components: D1: Figure 11 C2 Mainframe 1N4007 D2: T 5Z27 1J C1: 10µF/35V C2: 1nF/1000V RM: 75Ω/5W Test Circuit 1 TLE4942 - TLE4942C Data Sheet 16 February 2002 TLE4942, TLE4942C Package Outlines PSSO2-1 (Plastic Single Small Outline Package) TLE4942 - TLE4942C Data Sheet 17 February 2002 TLE4942, TLE4942C PSSO2-2 (Plastic Single Small Outline Package) TLE4942 - TLE4942C Data Sheet 18 February 2002