iC-MZ DIFFERENTIAL HALL SWITCH Rev A2, Page 1/11 FEATURES APPLICATIONS ♦ ♦ ♦ ♦ ♦ Gear wheel sensing ♦ Pole wheel and magnetic tape scanning ♦ Magnetic incremental encoders ♦ Proximity switches ♦ Two-channel line drivers up to 100 kHz ♦ ♦ ♦ ♦ ♦ ♦ ♦ Dual Hall sensors set 2.0 mm apart Magnetic field frequency range from DC to 40 kHz Supply voltage range 4.5 to 36 V Complementary push-pull line driver outputs with integrated line adaptation Output stages are current limited and short-circuit-proof due to temperature shutdown Min. 200 mA output current at 24 V supply voltage Low driver stage saturation voltage (< 0.4 V at 30 mA) RS422-compatible (TIA / EIA standard) Temperature and supply voltage monitor with error messaging Amplified differential sensor signal, accessible for diagnostic purposes Additional mode of operation (twofold line driver) PACKAGES DFN10 4 mm x 4 mm BLOCK DIAGRAM 4.5 ... 36 V VB D ND LINE VPA A NA NERR TEST GND1 Copyright © 2010 iC-Haus GND2 http://www.ichaus.com iC-MZ DIFFERENTIAL HALL SWITCH Rev A2, Page 2/11 DESCRIPTION Hall-effect device iC-MZ is a differential magnetic sensor used to scan pole wheels or ferromagnetic gear wheels. It contains two Hall sensors set 2.0 mm apart, a differential amplifier with a back-end comparator and a complementary line driver. A difference in field strength of the magnetic normal components at iC-MZ’s two Hall elements is amplified and evaluated as an analog signal and fed to the integrated line drivers as a complementary digital signal. The digital output signal tracks the change in sign of the field strength difference with a given hysteresis and thus provides a clear switch. switched to high impedance. Following a delay of about 200 µs the analog outputs are activated and the status of the two Hall sensors ist transmitted by the line drivers if the difference in field strength is sufficiently strong. With a moving gear or pole wheel the frequency of the tooth or pole pair corresponds to the frequency of the output signal. The amplified analog differential sensor signal is available for diagnostic purposes at pins A and NA. By activating the TEST input the device can be used as an independent two-channel line driver. In this case, the outputs D and ND are controlled by the inputs A and NA. Once the device has been switched on the digital outputs are initially in a predefined start state with D at low and ND at high; the analog outputs A and NA The complementary line drivers are suitable for supply voltages of 4.5 to 36 V with output impedances between 40 and 110 Ω. An integrated over temperature and undervoltage monitor switches the output stages to high impedance in the event of error and activates the open drain output NERR. The analog section of the iC-MZ circuit is fed by an internal supply of 5 V which is available at pin VPA for reference purpose. To improve signal quality, a capacitor can be connected to this pin. PACKAGES PIN CONFIGURATION PIN FUNCTIONS No. Name Function 1 10 2 9 3 4 5 iC-MZ ... ...yyww 8 7 6 1 2 3 4 5 6 7 8 9 10 GND1 D VB ND GND2 TEST NERR VPA NA A Ground Digital Output, not inverted Supply Voltage Digital Output, inverted Ground Linedriver Test Mode Error Output, open drain Internal 5 V Supply Voltage Analog Output, invertiert Analog Output, non invertierend For improved thermal dissipation the thermal pad on the package underside should be connected to ground in a suitable manner (ground plane). GND1 and GND2 should both be connected to ground. Orientation of the logo ( MZ CODE ...) is subject to alteration. iC-MZ DIFFERENTIAL HALL SWITCH Rev A2, Page 3/11 ABSOLUTE MAXIMUM RATINGS Beyond these values damage may occur; device operation is not guaranteed. Absolute Maximum Ratings are no Operating Conditions. Integrated circuits with system interfaces, e.g. via cable accessible pins (I/O pins, line drivers) are per principle endangered by injected interferences, which may compromise the function or durability. The robustness of the devices has to be verified by the user during system development with regards to applying standards and ensured where necessary by additional protective circuitry. By the manufacturer suggested protective circuitry is for information only and given without responsibility and has to be verified within the actual system with respect to actual interferences. Item No. Symbol Parameter Conditions Unit Min. Max. G001 VB Supply Voltage -0.4 40 V G002 V() Voltage at D, ND, NERR -0.4 40 V G003 V() Voltage at A, NA, TEST -0.4 6 V G004 I(VB) Current in VB -100 100 mA G005 I() Current in D, ND -600 600 mA G006 I(NERR) Current in NERR -10 30 mA G007 I() Current in A, NA, TEST -4 4 mA G008 Vd() Susceptibility to ESD at all pins 1 kV G009 Tj Operating Junction Temperature -40 150 °C G010 Ts Storage Temperature Range -40 150 °C HBM 100 pF discharged through 1.5 kΩ THERMAL DATA Operating Conditions: VB = 4.5..36 V, unless otherwise stated Item No. Symbol Parameter Conditions Unit Min. T01 Ta Operating Ambient Temperature Range T02 Rtjc Thermal Resistance Chip/Case T03 Rthja Thermal Resistance Chip/Ambient Typ. -40 Mounted on PCB, with thermal pad of 2 cm2 All voltages are referenced to ground unless otherwise stated. All currents flowing into the device pins are positive; all currents flowing out of the device pins are negative. Max. +125 °C 10 K/W 40 K/W iC-MZ DIFFERENTIAL HALL SWITCH Rev A2, Page 4/11 ELECTRICAL CHARACTERISTICS Operating Conditions: VB = 4.5..36 V, Tj = -40...135 °C unless otherwise stated Item No. Symbol Parameter Conditions Unit Min. Typ. Max. General 001 fmagn Magnetic Cut-off Frequency 002 VB Permissible Supply Voltage (upper 3 dB frequency corner) 003 I(VB) Supply Current in VB open outputs, fmagn = 0 004 |Hdc | Magnitude of mean magnetic field strength |Hdc | = |H1 + H2 | / 2, Outputs A, NA not saturated 005 |∆H| Maximal magnetic field difference |∆H| = |H1 − H2 | 006 Ht,hi Upper magnetic trigger threshold Output D lo → hi for ∆H > Ht,hi 007 Ht,lo lower magnetic trigger threshold 008 Ht,hys Hysteresis 009 Vc()lo Clamp Voltage lo at Pins VB, I() = -10 mA VPA, VPD, A, NA, D, ND, NERR, TEST 010 Vc()hi Clamp Voltage hi at Pins VB, NERR 011 Vc()hi 012 013 40 4.5 9 kHz 36 V 12 mA 400 kA/m 120 kA/m 2 kA/m Output D hi → lo for ∆H < Ht,lo -2 kA/m Ht,hys = Ht,hi − Ht,lo 4 kA/m -1.4 -0.35 V I(VB) = 10 mA, Test = hi, I(NERR) = 1 mA 37 50 V Clamp Voltage hi at Pins VPA, VPD, A, NA, TEST I(VPA, VPD) = 10 mA, I(A, NA, TEST) = 2 mA 6 20 V tsetup System enable from power on to activating outputs I(VB) Supply Current in VB, Test Mode open outputs, Test = hi (line driver mode) 200 400 µs 6 mA Temperatur Monitor 301 Toff Thermal Shutdown Threshold 145 175 °C 302 Ton Thermal Lock-on Threshold 135 165 °C 303 Thys Thermal Shotdown Hysteresis 20 °C kΩ Thys = Ton - Toff 5 10 Differential Outputs A, NA, Line Driver Test Mode 501 Rout() Output resistance 503 Vdc() Mean output voltage ∆H = 0 14 20 28 1.5 1.8 2.1 504 |∆V()| Output voltage difference |∆H| = 1kA/m, |∆V()| = |V(A) − V(NA)| 505 Vt()hi Input Threshold Voltage hi TEST = hi (Leitungstreibermodus) 506 Vt()lo Input Threshold Voltage lo TEST = hi (Leitungstreibermodus) 0.8 507 Vt()hys Input Hysteresis TEST = hi (Leitungstreibermodus) 0.2 508 Ipd() Pull-Down Current V() = 0.8 V, TEST = hi 509 Ipd() Pull-Down Current V() = 5.5 V, TEST = hi 70 V mV 2 V V 0.4 0.6 V 10 100 µA 20 200 µA Error Output NERR 601 Vs()lo Saturation Voltage lo at NERR 602 Isc()lo Short-Circuit Current lo in NERR V(NERR) = 2 V...VB, NERR = lo I(NERR) = 2.5 mA, NERR = lo 603 Ilk() Leakage Current in NERR V(NERR) = 5.5 V...VB, NERR = hi -10 604 VB Supply Voltage VB for NERR Function I(NERR) = 2.5 mA, NERR = lo, Vs(NERR) < 0.4 V 3.2 605 Rpu() Pull-Up-Resistor at NERR V(NERR) = 0...4.5 V 1 2.5 5.5 MΩ Test Mode = off, V(TEST) ≤ VPA 11 20 36 kΩ 2 V 4 12 0.4 V 25 mA 10 µA V Test Mode NERR, TEST 704 Rpd(TEST) Pull-Down Resistor at TEST 710 Vt(TEST)hi Threshold Voltage hi at TEST 711 Vt(TEST)lo Threshold Voltage lo at TEST 0.8 712 Vt(TEST)hy Hysteresis 0.2 713 Vt(NERR)hi Threshold Voltage hi at NERR Test = hi V 0.4 0.6 V 2.5 V iC-MZ DIFFERENTIAL HALL SWITCH Rev A2, Page 5/11 ELECTRICAL CHARACTERISTICS Operating Conditions: VB = 4.5..36 V, Tj = -40...135 °C unless otherwise stated Item No. Symbol Parameter Conditions Unit Min. Typ. Max. Line Driver D, ND 801 Vs()hi Saturation Voltage high Vs()hi = VB - V(), I() = -10 mA, output = hi 0.2 V 802 Vs()hi Saturation Voltage high Vs()hi = VB - V(), I() = -30 mA, output = hi 0.4 V 803 Isc()hi Short circuit current high V() = VB - 1.5 V, output = hi -70 -50 -35 mA 804 Isc()hi Short circuit current high V(Ax) = 0 V, output = hi -600 805 Rout()hi Output resistance VB = 10...36 V, V() =0.5 * VB 40 75 110 806 SR()hi Slew Rate high VB= 36 V, Cl() = 100 pF 100 250 807 Vc()hi Free Wheel Clamp Voltage high I() = 100 mA, VB = VCC = GND 0.5 808 Vs()lo Saturation Voltage low 809 Vs()lo Saturation Voltage low 810 Isc()lo Short circuit current low V() = 1.5 V, output = lo 811 Isc()lo Short circuit current low V() = VB, output = low 812 Rout()lo Output resistance 813 SR()lo 814 815 816 mA Ω V/µs 1.3 V I() = 10 mA, output = lo 0.2 V I() = 30 mA, output = lo 0.4 V 70 mA 600 mA 35 50 VB = 10...36 V, V() = 0.5 * VB 40 75 Slew Rate low VB = 36 V, Cl() = 100 pF 100 250 Vc()lo Free Wheel Clamp Voltage low I() = -100 mA -1.3 -0.5 V Ilk() Leakage Current in D, ND VB < VBoff; V() = 0...VBoff -10 10 µA Ilk() Leakage Current in D, ND T > Toff; V() = 0...VB -10 10 µA 4.45 V 110 Ω V/µs VB Voltage Monitor 901 VBon Turn-on Threshold VB 902 VBoff Turn-off Threshold VB 903 VBhys Hysteresis VPAhys = VPAon − VPAoff 100 200 907 V(VPA) Voltage at VPA VB > 5 V 4.5 5 908 V(VPA) Voltage at VPA VB ≤ 5 V 4 3.2 V mV 5.5 V 5 V iC-MZ DIFFERENTIAL HALL SWITCH Rev A2, Page 6/11 DEFINITION OF MAGNETIC FIELDS AND SENSOR OUTPUT SIGNALS In essence iC-MZ is non-magnetic and thus has practically no effect on the magnetic field to be scanned. The Hall sensors on the topside of the chip or at package level (x, y) are sensing the z component Hz of the magnetic field vector at the site of each sensor. Magnetic field component Hz counts as a positive when the field lines emerge on the printed upper side of the chip. The source of the magnetic field (magnets, coils) can be placed above or below (back bias) the iC package. In accordance with Figure 2 a distinction can be made between the different position and polarity of a magnet from the sign of the sensor signal. Following the amplification of the Hall voltage difference a differential analog signal V(A) or V(NA) is available at pins A and NA with a mean voltage of Vdc (Figure 3). If ∆H exceeds a limit of Ht,hi , digital output D switches to high. If ∆H undershoots a threshold of Ht,lo , output D is switched back to low. The switching status complementary to D is available at output ND. If differential field strength ∆H lies within the Ht,lo ..Ht,hi interval, the momentary switching status of the driver outputs does not change. M Z +B N V M Z S +B V(A) N S z Vdc y V(NA) x Figure 1: Example magnet positions in relation to iC-MZ The difference ∆H between z components H1 and H2 of the magnetic field strengths at the site of the two Hall sensors S1 and S2 is significant for the electrical output signal. H 0 Figure 3: Analog signals A and NA as a function of the difference in field strength ∆H V(D) ∆H = H1 − H2 Ht,hys = Ht,hi – Ht,lo S N M Z S1 S1 H1 H1 S2 Pin 1 Pin 1 H2 z VB S M Z N S2 H2 H>0 H<0 y Ht,lo 0 Ht,hi H x Figure 2: Definition of the difference in field strength ∆H Figure 4: Digital output D in dependence on the difference in field strength ∆H iC-MZ DIFFERENTIAL HALL SWITCH Rev A2, Page 7/11 HALL SENSOR POSITION The position of the two Hall sensors S1 and S2 is shown in Figure 5 (top view). 0.4 typ. z x side view 2,0 | S2 | S1 | < 0.2 0,14 | < 0.2 S1 y S2 x center of chip center of chip | | < 3° y Figure 5: Position of Hall sensors S1 and S2 in relation to the chip center (dimensions in mm) x top view Figure 6: Maximum placement error of the chip (exaggerated view) in a DFN10 package (dimensions in mm) The position tolerances of the chip within the DFN10 package are given in Figure 6. LINE DRIVER MODE iC-MZ’s line driver mode is activated by TEST = high, i.e. by a supply of VPA = 5 V. Pins A and NA then function as independent inputs for line driver outputs D and ND. When pins A and NA are connected together and used as common input, D and ND acts as buffered and inverted outputs. 4.5 ... 36 V VB SUPPLY HALL SENSOR AMPLIFIER A/D LINE DRIVER D B B ND LINE VPA 5V ANALOG BUFFER A NA TEMPERATUR MONITOR ERROR CONTROL NERR 1 TEST > 145 °C 5V Rpu TEST iC-MZ GND1 GND2 Figure 7: iC-MZ in line driver mode iC-MZ DIFFERENTIAL HALL SWITCH Rev A2, Page 8/11 APPLICATON NOTES The complementary line driver couples the output signals via lines to industrial 24 V systems. Due to the possible event of short circuiting in the line the drivers are current limited and shut down with excessive temperature. The maximum possible signal frequency depends on the capacitive loading of the outputs (line length) or the power dissipation in iC-MZ caused by such. With an unloaded output the maximum output voltage is equivalent to supply VB - with the exception of the saturation voltages. 40 36 VB = 36 V 32 V(D, ND) [V] 28 24 20 16 LINE EFFECTS With 24 V signals data is often transmitted without the line beeing terminated with the characteristic impedance. Mismatched line terminations such as these cause reflections which travel back and forth if no suitable adjustments have been made at the driver end of the setup. With rapid pulse trains transmission is then disrupted. In iC-MZ the reflection of return signals is hindered by an integrated impedance adapter. On pulse transmission the amplitude at the iC-MZ output first rises to approximately half the value of supply voltage VB as the internal driver resistor and the line impedance adapter form a voltage divider. Following a delay determined by the length of the line the impedance coupled into the line in this way is reflected at the high impedance end of the setup and travels back towards the driver. As the latter is well adjusted to the line by its interior resistor, the return pulse is largely absorbed. Fast signals can thus also be transmitted in this manner along lines with a characteristic impedance of between 40 and 110 Ω. 12 VB = 24 V 8 4 0 0 100 200 300 400 500 - I(D, ND) [mA] Figure 8: Load dependence of the output voltage Figure 8 illustrates the typical highside output characteristics of a driver acting as a load for two different supply voltages. Across a wide range the differential output resistance is typically 75 Ω. BOARD LAYOUT The thermal dissipation of iC-MZ is improved by connecting the thermal pad on the underside to a large area of copper on the board. Blocking capacitors used to filter the local iC supply should be connected up to the VB and GND package pins across the shortest possible distance. NERR connection Excessive temperature and overvoltage errors are indicated at output NERR. In normal operating mode the pin is at high impedance (open drain); it is switched to GND in the event of error. It can be connected up to VB via an external resistor. If NERR is not used, it must be left open and not be connected to GND. iC-MZ DIFFERENTIAL HALL SWITCH Rev A2, Page 9/11 APPLICATION EXAMPLES Gear wheel scanning Logging the position and rotation of a gear wheel with iC-MZ requires that the gear wheel is made of a soft magnetic basic material with which a magnetic field applied externally through the gear geometry can be modulated. The strength of the modulation is greatest at the gear rim, calling for iC-MZ to be placed at the shortest possible operating distance to the gear wheel. The necessary external bias field is generated by a back bias magnet placed behind iC-MZ. The magnet should be positioned central to the package so that the two Hall sensors are impinged by equal magnetic field strengths and a field strength offset is avoided; the latter would make a greater difference in modulation field strength necessary for switching purposes. Field homogeneity can be improved by placing a pole piece between the magnet and iC-MZ. gear wheel P B1 B2 S1 iC-MZ S2 N S bias magnet B B2 bias field B1 B1-B2 The strength of the magnetic field modulation depends not just on the operating distance and the intensity of the bias field but also on the module and addendum of the gear wheel. The distance of the teeth along the perimeter of the wheel stipulates the cycle with which the magnetic field strength is modulated. An optimum modulation depth is achieved when the gear wheel geometry is selected so that the two Hall sensors on the chip are opposite a tooth or a gap and the sensors provide signals in antiphase. With the given iC-MZ sensor distance of 2 mm a tooth distance of about 4 mm is advantageous but not imperative. Even if the geometry of the wheel is not adapted to suit the sensor, the signals generated by the two Hall sensors share a fixed phase relation. Figure 9 illustrates the typical course of magnetic induction B = µ0 · H at the two Hall sensors, dependent on angle of rotation φ of the gear wheel. In an ensuing amplification process analog signals VA and VNA are formed from the differential signal; digital signals VD and VND are generated by the back-end comparator with hysteresis. P BT,hi BT,l o 0 V P/2 VNA 0 3P/2 VA P/2 Vdc P VD 3P/2 VB P/2 VND P 3P/2 P 3P/2 VB P/2 Figure 9: Gear wheel scanning iC-MZ DIFFERENTIAL HALL SWITCH Rev A2, Page 10/11 Pole wheel scanning Pole wheels have a cyclic magnetization along their perimeter which is used for the magnetic modulation of iC-MZ. The intensity of the magnetic field is greatest along the perimeter and significantly diminishes with an increase in distance , so that iC-MZ should be placed as close to the pole wheel as possible. pole wheel P SS N N The magnetic subdivision along the pole wheel perimeter is repeated by a cycle P; iC-MZ’s electrical output signals also demonstrate this periodicity. The pole wheel is optimally adjusted when the Hall sensors are activated in antiphase, i.e. the distance of the Hall sensors is equivalent to just half a magnetic cycle. With iC-MZ this is the case when P = 4 mm. B1 S1 S2 iC-MZ B2 B B1 B2 P 3P/2 P/2 The dimensions of a pole wheel and its magnetic subdivision are often stipulated by the application so that the signals provided by the two Hall sensors are no longer in antiphase but in an arbitrary yet fixed phase relation to one another. B1-B2 P BT,hi BT,l o 0 V P/2 VA 0 3P/2 VNA P/2 Vdc The differential signal and the analog and digital iC-MZ output signals derived from it in dependence on the angle of rotation of a pole wheel are shown in Figure 10. 3P/2 P VD VB P/2 P VND 3P/2 VB P/2 P 3P/2 Figure 10: Pole wheel scanning iC-Haus expressly reserves the right to change its products and/or specifications. An Infoletter gives details as to any amendments and additions made to the relevant current specifications on our internet website www.ichaus.de/infoletter; this letter is generated automatically and shall be sent to registered users by email. Copying – even as an excerpt – is only permitted with iC-Haus approval in writing and precise reference to source. iC-Haus does not warrant the accuracy, completeness or timeliness of the specification on this site and does not assume liability for any errors or omissions in the materials. The data specified is intended solely for the purpose of product description. No representations or warranties, either express or implied, of merchantability, fitness for a particular purpose or of any other nature are made hereunder with respect to information/specification or the products to which information refers and no guarantee with respect to compliance to the intended use is given. In particular, this also applies to the stated possible applications or areas of applications of the product. iC-Haus conveys no patent, copyright, mask work right or other trade mark right to this product. iC-Haus assumes no liability for any patent and/or other trade mark rights of a third party resulting from processing or handling of the product and/or any other use of the product. As a general rule our developments, IPs, principle circuitry and range of Integrated Circuits are suitable and specifically designed for appropriate use in technical applications, such as in devices, systems and any kind of technical equipment, in so far as they do not infringe existing patent rights. In principle the range of use is limitless in a technical sense and refers to the products listed in the inventory of goods compiled for the 2008 and following export trade statistics issued annually by the Bureau of Statistics in Wiesbaden, for example, or to any product in the product catalogue published for the 2007 and following exhibitions in Hanover (Hannover-Messe). We understand suitable application of our published designs to be state-of-the-art technology which can no longer be classed as inventive under the stipulations of patent law. Our explicit application notes are to be treated only as mere examples of the many possible and extremely advantageous uses our products can be put to. iC-MZ DIFFERENTIAL HALL SWITCH Rev A2, Page 11/11 ORDERING INFORMATION Type Package Order Designation iC-MZ DFN10 iC-MZ DFN10 For technical support, information about prices and terms of delivery please contact: iC-Haus GmbH Am Kuemmerling 18 D-55294 Bodenheim GERMANY Tel.: +49 (61 35) 92 92-0 Fax: +49 (61 35) 92 92-192 Web: http://www.ichaus.com E-Mail: [email protected] Appointed local distributors: http://www.ichaus.com/sales_partners