AS5304 / AS5306 Integrated Hall ICs for Linear and Off-Axis Rotary Motion Detection 1 General Description PRELIMINARY DATA SHEET 2 The AS5304/AS5306 are single-chip IC’s with integrated Hall elements for measuring linear or rotary motion using multi-pole magnetic strips or rings. This allows the usage of the AS5304/AS5306 in applications where the Sensor IC cannot be mounted at the end of a rotating device (e.g. at hollow shafts). Instead, the AS5304/AS5306 are mounted off-axis underneath a multipole magnetized ring or strip and provides a quadrature incremental output with 40 pulses per pole period at speeds of up to 20 meters/sec (AS5304) or 12 meters/sec (AS5306). Benefits • Complete system-on-chip • High reliability due to non-contact sensing • Suitable for the use in harsh environments • Robust against external magnetic stray fields 3 Key Features • High speed, up to 20m/s (AS5304) 12m/s (AS5306) • Magnetic pole pair length: 4mm (AS5304) or 2.4mm (AS5306) • Resolution: 25µm (AS5304) or 15µm (AS5306) Using, for example, a 32pole-pair magnetic ring, the AS5304/AS5306 can provide a resolution of 1280 pulses/rev, which is equivalent to 5120 positions/rev or 12.3bit. The maximum speed at this configuration is 9375 rpm. • 40 pulses / 160 positions per magnetic period. • 1 index pulse per pole pair • Linear movement magnetic strips The pole pair length is 4mm (2mm north pole / 2mm south pole) for the AS5304, and 2.4mm (1.2mm north pole / 1.2mm south pole) for the AS5306. The chip accepts a magnetic field strength down to 5mT (peak). • Circular off-axis movement measurement using multipole magnetic rings • 4.5 to 5.5V operating voltage • Magnetic field strength indicator, magnetic field alarm for end-of-strip or missing magnet A single index pulse is generated once for every pole pair at the Index output. Both chips are available with push-pull outputs (AS530xA) or with open drain outputs (AS530xB). The AS5304/AS5306 are available in a small 20-pin TSSOP package and specified for an operating ambient temperature of -40° to +125°C. Figure 1: Revision 1.6 AS5304 (AS5306) with multi-pole ring magnet. 4 measurement using multi-pole Applications The AS5304/AS5306 are ideal for high speed linear motion and off-axis rotation measurement in applications such as • electrical motors • X-Y-stages • rotation knobs • industrial drives Figure 2: www.austriamicrosystems.com AS5306 (AS5304) with magnetic multi-pole strip magnet for linear motion measurement Page 1 of 13 AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection 5 Functional Description The AS5304/AS5306 require a multi-pole magnetic strip or ring with a pole length of 2mm (4mm pole pair length) on the AS5304, and a pole length of 1.2mm (2.4mm pole pair length) on the AS5306. The magnetic field strength of the multi-pole magnet should be in the range of 5 to 60mT at the chip surface. The Hall elements on the AS5304/AS5306 are arranged in a linear array. By moving the multi-pole magnet over the Hall array, a sinusoidal signal (SIN) is generated internally. With proper configuration of the Hall elements, a second 90° phase shifted sinusoidal signal (COS) is obtained. Using an interpolation circuit, the length of a pole pair is divided into 160 positions and further decoded into 40 quadrature pulses. An Automatic Gain Control provides a large dynamic input range of the magnetic field. An Analog output pin (AO) provides an analog voltage that changes with the strength of the magnetic field (see chapter 8). Figure 3: 6 AS5304 / AS5306 block diagram Sensor Placement in Package 1.02 TSSOP20 / 0.65mm pin pitch Die C/L 0.2299±0.100 3.200±0.235 0.2341±0.100 Package Outline 0.7701±0.150 3.0475±0.235 Figure 4: Sensor in package Die Tilt Tolerance ±1º Revision 1.6 www.austriamicrosystems.com Page 2 of 13 AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection 6.1 Pin Description Pin Pin Name Pin Type 1 VSS S 2 A DO_OD 3 VDDP S 4 B DO_OD 5,12,13, 14,17,18,19 TEST AIO test pins, must be left open 6 AO AO AGC Analogue Output. (Used to detect low magnetic field strength) 7 VDD S 8 Index DO_OD 9,10,11 TEST AIO 15 TEST_GND S test pin, must be connected to VSS 16 VDDA Hall S Hall Bias Supply Support (connected to VDD) 20 ZPZmskdis DI Test input, connect to VSS during operation PIN Types: 6.2 S AIO DO_OD Notes Supply ground Incremental quadrature position output A. Short circuit current limitation Peripheral supply pin, connect to VDD Incremental quadrature position output B. Short Circuit Current Limitation Positive supply pin Index output, active HIGH. Short Circuit Current Limitation test pins, must be left open supply pin AO analogue output analog input / output DI digital input digital output push pull or open drain (programmable) Package Drawings and Markings 20 Lead Thin Shrink Small Outline Package – TSSOP20 Revision 1.6 www.austriamicrosystems.com Page 3 of 13 AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection Dimensions Marking: AYWWIZZ mm inch Symbol Min Typ Max Min Typ Max A - - 1.20 - - 0.047 A1 0.05 - 0.15 0.002 - 0.006 A2 0.80 1.00 1.05 0.031 0.039 0.041 b 0.19 - 0.30 0.007 - 0.012 c 0.09 - 0.20 0.004 - 0.008 D 6.40 6.50 6.60 0.252 0.256 0.260 E 6.40 E1 4.30 e 6.3 4.40 4.50 0.169 0.173 JEDEC Package Outline Standard: MO-153-AC Thermal Resistance R th(j-a) : 89 K/W in still air, soldered on PCB. 0.252 0.65 A: Pb-Free Identifier Y: Last Digit of Manufacturing Year WW: Manufacturing Week I: Plant Identifier ZZ: Traceability Code 0.177 0.0256 K 0° - 8° 0° - 8° L 0.45 0.60 0.75 0.018 0.024 0.030 IC's marked with a white dot or the letters "ES" denote Engineering Samples Electrical Connection The supply pins VDD, VDDP and VDDA are connected to +5V. Pins VSS and TEST_GND are connected to the supply ground. A 100nF decoupling capacitor close to the device is recommended. Figure 5: Revision 1.6 Electrical connection of the AS5304/AS5306 www.austriamicrosystems.com Page 4 of 13 AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection 7 Incremental Quadrature AB Output The digital output is compatible to optical incremental encoder outputs. Direction of rotation is encoded into two signals A and B that are phase-shifted by 90º. Depending on the direction of rotation, A leads B (CW) or B leads A (CCW). S N 40 7.1.1 Index Pulse 1 S N 2 40 1 S 2 A A single index pulse is generated once for every pole pair. One pole pair is interpolated to 40 quadrature pulses (160 steps), so one index pulse is generated after every 40 quadrature pulses (see Figure 6) 40 1 2 40 1 2 B Index The Index output is switched to Index = high, when a magnet is placed over the Hall array as shown in Figure 7, top graph: the north pole of the magnet is placed over the left side of the IC (top view, pin#1 at bottom left) and the south pole is placed over the right side of the IC. The index output will switch back to Index = low, when the magnet is moved by one LSB from position X=0 to X=X1, as shown in Figure 7, bottom graph. One LSB is 25µm for AS5304 and 15µm for AS5306. Note: Since the small step size of 1 LSB is hardly recognizable in a correctly scaled graph it is shown as an exaggerated step in the bottom graph of Figure 7. Detail: A B Index Step # 157 158 159 Figure 6: 7.1.2 0 1 2 3 4 5 Quadrature A / B and Index output Magnetic Field Warning Indicator The AS5304 can also provide a low magnetic field warning to indicate a missing magnet or when the end of the magnetic strip has been reached. This condition is indicated by using a combination of A, B and Index, that does not occur in normal operation: A low magnetic field is indicated with: Index = high A=B=low 7.1.3 Vertical Distance between Magnet and IC The recommended vertical distance between magnet and IC depends on the strength of the magnet and the length of the magnetic pole. Typically, the vertical distance between magnet and chip surface should not exceed ½ of the pole length. That means for AS5304, having a pole length of 2.0mm, the maximum vertical gap should be 1.0mm, For the AS5306, having a pole length of 1.2mm, the maximum vertical gap should be 0.6mm These figures refer to the chip surface. Given a typical distance of 0.2mm between chip surface and IC package surface, the recommended vertical distances between magnet and IC surface are therefore: AS 5304: ≤ 0.8mm AS 5306: ≤ 0.4mm Revision 1.6 www.austriamicrosystems.com Page 5 of 13 X=0 AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection Magnet drawn at index position X=0 X CW magnet movement direction N S 4.220±0.235 Hall Array Center Line Index = High Pin 1 Chip Top view 3.0475±0.235 X X=X1 X=0 25µm (AS5304) 15µm (AS5306) Magnet drawn at position X1 (exaggerated) CW magnet movement direction N S 4.220±0.235 Hall Array Center Line Index = Low Pin 1 Chip Top view 3.0475±0.235 Figure 7: 7.1.4 Magnet placement for index pulse generation Soft Stop Feature for Linear Movement Measurement When using long multi-pole strips, it may often be necessary to start from a defined home (or zero) position and obtain absolute position information by counting the steps from the defined home position. The AS5304/AS5306 provide a soft stop feature that eliminates the need for a separate electro-mechanical home position switch or an optical light barrier switch to indicate the home position. The magnetic field warning indicator (see 7.1.2) together with the index pulse can be used to indicate a unique home position on a magnetic strip: 1. First the AS5304/AS5306 move to the end of the strip, until a magnetic field warning is displayed (Index = high, A=B=low) 2. Then, the AS5304/AS5306 move back towards the strip until the first index position is reached (note: an index position is generated once for every pole pair, it is indicated with: Index = high, A=B= high). Depending on the polarity of the strip magnet, the first index position may be generated when the end of the magnet strip only covers one half of the Hall array. This position is not recommended as a defined home position, as the accuracy of the AS5304/AS5306 are reduced as long as the multi-pole strip does not fully cover the Hall array. Revision 1.6 www.austriamicrosystems.com Page 6 of 13 AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection 3. 7.2 It is therefore recommended to continue to the next (second) index position from the end of the strip (Index = high, A=B= high). This position can now be used as a defined home position. Incremental Hysteresis I ncrem en tal o ut put If the magnet is sitting right at the transition point between two steps, the noise in the system may cause the incremental outputs to jitter back and forth between these two steps, especially when the magnetic field is weak. H ys teres is: 1 LS B X +4 X +3 X +2 X +1 M agnet position X X X+1 X+2 X+ 3 X+4 Note: 1LSB = 25µm for AS5304, 15µm for AS5306 Mov ement d ir ection: +X M ovem ent direc tion: -X Figure 8: 7.3 To avoid this unwanted jitter, a hysteresis has been implemented. The hysteresis lies between 1 and 2 LSB, depending on device scattering. Figure 8 shows an example of 1LSB hysteresis: the horizontal axis is the lateral position of the magnet as it scans across the IC, the vertical axis is the change of the incremental outputs, as they step forward (blue line) with movement in +X direction and backward (red line) in –X direction. Hysteresis of the incremental output Integral Non-Linearity (INL) The INL (integral non-linearity) is the deviation between indicated position and actual position. It is better than 1LSB for both AS5304 and AS5306, assuming an ideal magnet. Pole length variations and imperfections of the magnet material, which lead to a non-sinusoidal magnetic field will attribute to additional linearity errors. 7.3.1 Error Caused by Pole Length Variations Error [µm] AS5304 Systematic Linearity Error caused by Pole Length Deviation 140 120 100 80 60 40 20 0 1500 Figure 9 and Figure 10 show the error caused by a non-ideal pole length of the multi-pole strip or ring. Error [µm] This is less of an issue with strip magnets, as they can be manufactured exactly to specification using the proper magnetization tooling. 1700 1900 2100 2300 2500 Pole Length [µm] Figure 9: Additional error caused by pole length variation: AS5304 Error [µm] AS5306 Systematic Linearity Error caused by Pole Length Deviation 140 120 100 80 60 40 20 0 However, when using a ring magnet (see Figure 1) the pole length differs depending on the measurement radius. For optimum performance it is therefore essential to mount the IC such that the Hall sensors are exactly underneath the magnet at the radius where the pole length is 2.0mm (AS5304) or 1.2mm (AS5306), see also 8.1.2. Error [µm] 900 1000 1100 1200 1300 1400 1500 Note that this is an additional error, which must be added to the intrinsic errors INL (see 7.3) and DNL (see 7.4). Pole Length [µm] Figure 10: Revision 1.6 Additional error caused by pole length variation: AS5306 www.austriamicrosystems.com Page 7 of 13 AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection 7.4 Dynamic Non-Linearity (DNL) incremental output steps AS5304 AS5304: 5304: DNL (dynamic nonnon-linearity) linearity) 1 LSB - DNL 12. 12.5 µm 1 LSB 25 µm incremental output steps The DNL (dynamic non-linearity) describes the non-linearity of the incremental outputs from one step to the next. In an ideal system, every change of the incremental outputs would occur after exactly one LSB (e.g. 25µm on AS5304). In practice however, this step size is not ideal, the output state will change after 1LSB +/-DNL. The DNL must be <+/- ½ LSB to avoid a missing code. Consequently, the incremental outputs will change when the magnet movement over the IC is minimum 0.5 LSB and maximum 1.5 LSB’s. AS5306 AS5306: 5306: DNL (dynamic nonnon-linearity) linearity) 1 LSB + DNL 37. 37.5 µm 1 LSB - DNL 7.5 µm 1 LSB 15 µm 1 LSB + DNL 22. 22.5 µm lateral magnet movement Figure 11: 8 lateral magnet movement DNL of AS5304 (left) and AS5306 (right) The AO Output The Analog Output (AO) provides an analog output voltage that represents the Automatic Gain Control (AGC) of the Hall sensors signal control loop. This voltage can be used to monitor the magnetic field strength and hence the gap between magnet and chip surface: • Short distance between magnet and IC → strong magnetic field → low loop gain → low AO voltage • Long distance between magnet and IC → weak magnetic field → high loop gain → high AO voltage For ideal operation, the AO voltage should be between 1.0 and 4.0V (typical; see 9.5). Figure 12: Revision 1.6 AO output versus AGC, magnetic field strength, magnet-to-IC gap www.austriamicrosystems.com Page 8 of 13 AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection 8.1 Resolution and Maximum Rotating Speed When using the AS5304/AS5306 in an off-axis rotary application, a multi-pole ring magnet must be used. Resolution, diameter and maximum speed depend on the number of pole pairs on the ring. 8.1.1 Resolution The angular resolution increases linearly with the number of pole pairs. One pole pair has a resolution (= interpolation factor) of 160 steps or 40 quadrature pulses. Resolution [steps] = [interpolation factor] x [number of pole pairs] Resolution [bit] = log (resolution[steps]) / log (2) Example: multi-pole ring with 22 pole pairs Resolution = 160x22 = 3520 steps per revolution = 40x22 = 880 quadrature pulses / revolution = 11.78 bits per revolution = 0.1023° per step 8.1.2 Multi-pole Ring Diameter The length of a pole pair across the median of the multi-pole ring must remain fixed at either 4mm (AS5304) or 2.4mm (AS5306). Hence, with increasing pole pair count, the diameter increases linearly with the number of pole pairs on the magnetic ring. Magnetic ring diameter = [pole length] * [number of pole pairs] / π for AS5304: d = 4.0mm * number of pole pairs / π for AS5306: d = 2.4mm * number of pole pairs / π Example: same as above: multi-pole ring with 22 pole pairs for AS5304 Ring diameter = 4 * 22 / 3.14 = 28.01mm (this number represents the median diameter of the ring, this is where the Hall elements of the AS5304/AS5306 should be placed; see Figure 4) For the AS5306, the same ring would have a diameter of: 2.4 * 22 / 3.14 = 16.8mm 8.1.3 Maximum Rotation Speed The AS5304/AS5306 use a fast interpolation technique allowing an input frequency of 5kHz. This means, it can process magnetic field changes in the order of 5000 pole pairs per second or 300,000 revolutions per minute. However, since a magnetic ring consists of more than one pole pair, the above figure must be divided by the number of pole pairs to get the maximum rotation speed: Maximum rotation speed = 300,000 rpm / [number of pole pairs] Example: same as above: multi-pole ring with 22 pole pairs: Max. speed = 300,000 / 22 = 13,636 rpm (this is independent of the pole length) 8.1.4 Maximum Linear Travelling Speed For linear motion sensing, a multi-pole strip using equally spaced north and south poles is used. The pole length is again fixed at 2.0mm for the AS5304 and 1.2mm for the AS5306. As shown in 8.1.3 above, the sensors can process up to 5000 pole pairs per second, so the maximum travelling speed is: Maximum linear travelling speed = 5000 * [pole pair length] Example: linear multi-pole strip: Max. linear travelling speed = 4mm * 5000 1/sec = 20,000mm/sec = 20m/sec for AS5304 Max. linear travelling speed = 2.4mm * 5000 1/sec = 12,000mm/sec = 12m/sec for AS5306 Revision 1.6 www.austriamicrosystems.com Page 9 of 13 AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection 9 9.1 GENERAL DEVICE SPECIFICATIONS Absolute Maximum Ratings (Non Operating) Stresses beyond those listed under “Absolute Maximum Ratings“ may cause permanent damage to the device. Parameter Symbol Min Max Unit VDD -0.3 7 V Input pin voltage V in VSS-0.5 VDD+0.5 V Input current (latchup immunity) I scr -100 100 mA Norm: JESD78 kV Norm: MIL 883 E method 3015 114.5 °C /W Still Air / Single Layer PCB 150 °C 260 °C 5 85 % Min Typ Max Unit 4.5 5.0 5.5 V 0.0 0.0 0.0 V Supply ESD +/-2 Package thermal resistance Θ JA Storage temperature T strg Soldering conditions T body -55 Humidity non-condensing 9.2 Note Norm: IPC/JEDEC J-STD-020C Operating Conditions Parameter Symbol Positive supply voltage AVDD Digital supply voltage DVDD Negative supply voltage Power supply current, AS5304 VSS IDD Power supply current, AS5306 25 35 20 30 mA Ambient temperature T amb -40 125 °C Junction temperature TJ -40 150 °C Resolution LSB Integral nonlinearity INL 1 LSB Differential nonlinearity DNL ±0.5 LSB Hysteresis Hyst 1 2 LSB Parameter Symbol Min Power up time Propagation delay 9.3 25 15 µm 1.5 Note A/B/Index, AO unloaded! AS5304 AS5306 Ideal input signal (ErrMax - ErrMin) / 2 No missing pulses. optimum alignment System Parameters Revision 1.6 Max Unit Note T PwrUp 500 µs Amplitude within valid range / Interpolator locked, A B Index enabled T Prop 20 µs Time between change of input signal to output signal www.austriamicrosystems.com Page 10 of 13 AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection 9.4 A / B / C Push/Pull or Open Drain Output Push Pull Mode is set for AS530xA, Open Drain Mode is set for AS530xB versions. Parameter Symbol Min Typ Max High level output voltage V OH 0.8 VDD Low level output voltage V OL Current source capability I LOH 12 14 mA Current sink capability I LOL 13 15 mA Short circuit limitation current I Short 25 Capacitive load CL Load resistance RL Rise time tR Fall time tF 0.4 + VSS Unit Note V Push/Pull mode V Push/Pull mode mA Reduces maximum operating temperature 20 pF See Figure 13 820 Ω See Figure 13 1.2 µs Push/Pull mode 1.2 µs 39 VDD = 5V RL = 820Ω A/B/Index from AS5304/6 TTL 74LS00 CL = 20pF Figure 13: 9.5 Typical digital load CAO Analogue Output Buffer Parameter Symbol Min Typ Max Unit Note Minimum output voltage V OutRange 0.5 1 1.2 V Strong field, min. AGC Maximum output voltage V OutRange 3.45 4 4.3 V Weak field, max. AGC ±10 mV Offset Current sink / source capability Average short circuit current V Offs IL 5 I Short 6 mA 40 mA Capacitive load CL 10 pF Bandwidth BW 5 KHz Revision 1.6 www.austriamicrosystems.com Reduces maximum Operating Temperature Page 11 of 13 AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection 9.6 Magnetic Input Parameter Symbol Magnetic pole length Min Typ Max 2.0 L P_FP Unit Note AS5304 mm 1.2 Magnetic pole pair length AS5306 4.0 T FP AS5304 mm 2.4 Magnetic amplitude A mag Operating dynamic input range Magnetic offset Magnetic temperature drift Input frequency Table 1: 60 1:12 1:24 mT ±0.5 mT T dmag -0.2 %/K 5 kHz 0 AS5304 ordering guide Resolution Magnet Pole Length Digital Outputs AS5304A 25µm 2mm Push Pull AS5304B 25µm 2mm Open Drain Resolution Magnet Pole Length Digital Outputs AS5306A 15µm 1.2mm Push Pull AS5306B 15µm 1.2mm Open Drain AS5306 ordering guide Device Revision 1.6 5 Off mag f mag Device Table 2: AS5306 www.austriamicrosystems.com Page 12 of 13 AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection Contact Headquarters austriamicrosystems AG A 8141 Schloss Premstätten, Austria Phone: +43 3136 500 0 Fax: +43 3136 525 01 www.austriamicrosystems.com Copyright Devices sold by austriamicrosystems are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. austriamicrosystems makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems reserves the right to change specifications and prices at any time and without notice. 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No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems rendering of technical or other services. Revision 1.6 www.austriamicrosystems.com Page 13 of 13