Online Documentation Design Resources Sample & Buy Discussion Integrated AMR Angle Sensor and Signal Conditioner ADA4571 Data Sheet FEATURES FUNCTIONAL BLOCK DIAGRAM VDD High precision 180° angle sensor Maximum angular error of 0.5° Analog sine and cosine outputs Ratiometric output voltages Low thermal and lifetime drift SAR or Σ-Δ analog-to-digital converter (ADC) drive capable Magnetoresistive (MR) bridge temperature compensation mode Temperature range: −40°C to +150°C EMI resistant Fault diagnostics VDD from 2.7 V to 5.5 V Minimum phase delay Qualified for automotive applications Available in an 8-lead SOIC package ADA4571 TEMPERATURE SENSOR GC BRIDGE DRIVER + EMI FILTER AMR BRIDGE SENSORS BIAS – OSCILLATOR EMI FILTER APPLICATIONS Absolute position measurement (linear and angle) Brushless dc motor control and positioning Actuator control and positioning Contactless angular measurement and detection Magnetic angular position sensing G = 40 VTEMP VSIN DRIVER FAULT DETECTION + – G = 40 GND GND DRIVER VCOS PD 12514-001 Product Overview Figure 1. GENERAL DESCRIPTION The ADA4571 is an anisotropic magnetoresistive (AMR) sensor with integrated signal conditioning amplifiers and ADC drivers. The ADA4571 produces two analog outputs that indicate the angular position of the surrounding magnetic field. The ADA4571 consists of two die within one package, an AMR sensor, and a fixed gain (G = 40 nominally) instrumentation amplifier. The ADA4571 delivers clean and amplified cosine and sine output signals related to the angle of a rotating magnetic field. The output voltage range is ratiometric to the supply voltage. The sensor contains two Wheatstone bridges, at a relative angle of 45° to one another. A rotating magnetic field in the x-y sensor plane delivers two sinusoidal output signals with the double frequency of the angle (α) between sensor and magnetic field direction. Within a homogeneous field in the x-y plane, the output signals are independent of the physical placement in the z direction (air gap). COMPANION PRODUCTS ADCs: AD7265, AD7266, AD7866, AD7902 Microconverter: ADuCM360 Current Sense Amplifier: AD8418A Voltage Regulator Design Tool: ADIsimPower Additional companion products on the ADA4571 product page PRODUCT HIGHLIGHTS 1. 2. 3. 4. 5. 6. 7. 8. Contactless angular measurement. Measures magnetic field direction rather than field intensity. Minimum sensitivity to air gap variations. Large working distance. Excellent accuracy, even for weak saturation fields. Minimal thermal and lifetime drift. Negligible hysteresis. Single chip solution. The ADA4571 is available in an 8-lead SOIC package. Rev. 0 Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 ©2014 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com Product Overview Design Resources Online Documentation ADA4571 Discussion Sample & Buy Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Pin Configuration and Descriptions...............................................8 Applications ....................................................................................... 1 Typical Performance Characteristics ..............................................9 Functional Block Diagram .............................................................. 1 Terminology .................................................................................... 13 General Description ......................................................................... 1 Theory of Operation ...................................................................... 14 Companion Products ....................................................................... 1 Applications Information .............................................................. 16 Product Highlights ........................................................................... 1 Angle Calculation ....................................................................... 16 Revision History ............................................................................... 2 Connection to ECU ................................................................... 16 Specifications..................................................................................... 3 Mechanical Tolerances Diagrams ............................................ 18 Magnetic Characteristics ............................................................. 3 Diagnostics .................................................................................. 19 Electrical Characteristics ............................................................. 3 Outline Dimensions ....................................................................... 21 Absolute Maximum Ratings ............................................................ 7 Ordering Guide .......................................................................... 21 Thermal Resistance ...................................................................... 7 Automotive Products ................................................................. 21 ESD Caution .................................................................................. 7 REVISION HISTORY 9/14—Revision 0: Initial Version Rev. 0 | Page 2 of 21 Online Documentation Product Overview Design Resources Sample & Buy Discussion Data Sheet ADA4571 SPECIFICATIONS MAGNETIC CHARACTERISTICS Table 1. Parameter Magnetic Field Strength, HEXT Value 25 Unit kA/m Maximum Magnetic Field Rotational Frequency Reference Position Error 50,000 rpm ±50 µm Reference Angle Error ±2 Degrees ELECTRICAL CHARACTERISTICS Test Conditions/Comments The stimulating magnetic field in the x-y sensor plane necessary to ensure the minimum error as specified in Table 1 and Table 2 Reference position for y = 0 µm is the straight connection line of Pin 2 and Pin 7; the x = 0 µm position is referred to the middle distance of the package top Reference position for angle Φ = 0° is parallel to the straight connection line of Pin 2 and Pin 7 ∠ ADA4571WH −40°C ≤ TA ≤ +150°C, VDD = 2.7 V to 5.5 V, CL = 10 nF to GND, RL = 200 kΩ to GND; angle inaccuracies referred to homogenous magnetic field of 25 kA/m; output signals and offset voltages are related to the common-mode level of VDD/2, unless otherwise stated. Table 2. Parameter ANGULAR PERFORMANCE Angle Measurement Range Uncorrected Angular Error 1 Symbol Test Conditions/Comments αUNCORR TA = −40°C TA = 25°C TA = 150°C TA = −40°C to +150°C, GC = GND αCAL Dynamic Angular Error 4 αDYNAMIC Max Unit 180 ±5 ±5 ±5 Degrees Degrees Degrees Degrees Degrees ±0.7 TA = −40°C to +150°C, GC = VDD TA = −40°C to +150°C, rotation frequency = 2000 rpm ±0.7 ±0.1 ±0.5 Degrees Degrees VAMP GC = VDD Output Voltage Range Output Voltage Low Output Referred Offset Voltage VO_SWING VOL VOFFSET Amplitude Synchronism Error 5 Delay Time Phase Error 6 Orthogonality Error3 Output Noise k tDEL ΦERR OE VNOISE Output Series Resistance RO Output −3 dB Cutoff Frequency3 Typ 0 Single Point Calibration Angular Error 2, 3 OUTPUT PARAMETERS Amplitude GC = GND Min f−3dB TA = −40°C TA = 25°C TA = 125°C TA = 150°C TA = −40°C TA = 25°C TA = 125°C TA = 150°C VSIN and VCOS, normal operation VSIN or VCOS, broken bond wire detected GC = VDD GC = GND 63 41 21 18 56 52 38 35 7 75 53 33 30 77 72 57 55 93 5 3.75 3.75 +1 −1 Rotation frequency = 30,000 rpm Rotation frequency = 30,000 rpm 2 0.8 Bandwidth (BW) = 80 kHz, referred to output (RTO) Normal operation, PD = GND PD = VDD Amplifier BW, CL = 10 pF 500 0.05 Rev. 0 | Page 3 of 21 60 63 100 % VDD % VDD % VDD % VDD % VDD % VDD % VDD % VDD % VDD % VDD % VDD % VDD % peak µs Degrees Degrees µV rms Ω kΩ kHz Design Resources Online Documentation Product Overview Sample & Buy Discussion ADA4571 Parameter Power Supply Rejection3 Output Short-Circuit Current Sensitivity POWER SUPPLY Supply Voltage Quiescent Supply Current Power-Up Time DIGITAL INPUTS Input Bias Current (GC) Input Bias Current (PD) Input Voltage (GC and PD) High Low TEMPERATURE SENSOR Error Over Temperature Temperature Voltage Range Temperature Coefficient VTEMP Output Voltage VTEMP Output Impedance VTEMP Load Capacitance VTEMP Short-Circuit Current LOAD CAPACITOR External Load Capacitance Data Sheet Symbol PSRR ISC SEN VDD ISY tPWRUP IB_GC IB_PD Test Conditions/Comments Measured as output variation from VDD/2, VDD = 2.7 V to 5.5 V, RL = 200 kΩ to GND, GC = GND or VDD Short to GND per pin (VSIN, VCOS) Short to VDD per pin (VSIN, VCOS) α1 = 0°, α2 = 135°, TA = 25°C PD = GND, GC = GND, no load PD = GND, GC = VDD, no load PD = VDD, no load To 98% of desired output level after VDD was reached To 98% of desired output level after PD cycling ISC_VTEMP CL Typ 80 15 −15 20 −18 52 2.7 3.5 For GC mode control pin, GC = GND For GC mode control pin, GC = VDD For PD pin, PD = GND For PD pin, PD = VDD VIH VIL TERR TRANGE TCO Min 4.5 Max mA mA mV/° 5.5 6.5 7 15 150 V mA mA µA µs 100 µs 30 30 µA µA µA µA 0.35 V V 3 3 1.4 5 TA = −40°C to +150°C 0 82 3.173 TA = 25°C Buffered output Optional load capacitance Short-circuit to VDD or GND Between VSIN to GND and VCOS to GND; solder close to package 18 40 50 0 2 Unit dB 22 10 °C % VDD mV/V/°C % VDD Ω nF mA nF αUNCORR is the total mechanical angular error after arctan computation. This parameter is 100% production tested at 25°C and 150°C. This error includes all sources of error over temperature before calibration. Error components such as offset, amplitude synchronism, amplitude synchronism drift, thermal offset drift, phase error, hysteresis, orthogonality error, and noise are included. 2 αCAL is the total mechanical angular error after arctan computation. This error includes all sources of error over temperature after an initial offset (nulling) is performed at TA = 25°C. Error components such as amplitude synchronism drift, amplifier gain matching, thermal offset drift, phase error, hysteresis, orthogonality error, and noise are included. 3 Guaranteed through characterization. 4 αDYNAMIC is the total mechanical angular error after arctan computation. This parameter is 100% production tested. This error includes all sources of error over temperature after a continuous background calibration is performed to correct offset and amplitude synchronism errors. Error components such as phase error, hysteresis, orthogonality error, noise, and lifetime drift are included. 5 Peak-to-peak amplitude mismatch. k = 100 × VSIN/VCOS. 6 Rotation frequency dependent phase error, after offset correction, amplitude calibration, and arctan calculation. 1 Rev. 0 | Page 4 of 21 Online Documentation Product Overview Design Resources Sample & Buy Discussion Data Sheet ADA4571 ADA4571B −40°C ≤ TA ≤ +125°C, VDD = 2.7 V to 5.5 V, CL = 10 nF to GND, RL = 200 kΩ to GND; angle inaccuracies referred to homogenous magnetic field of 25 kA/m; output signals and offset voltages are related to the common-mode level of VDD/2, unless otherwise stated. Table 3. Parameter ANGULAR PERFORMANCE Angle Measurement Range Uncorrected Angular Error 1 Symbol Test Conditions/Comments αUNCORR TA = −40°C TA = 25°C TA = 125°C TA = −40°C to +125°C, GC = GND αCAL Dynamic Angular Error 4 αDYNAMIC Angular Inaccuracy3, 5 ∆α Output Voltage Range Output Voltage Low Output Referred Offset Voltage VO_SWING VOL VOFFSET Amplitude Synchronism Error 6 Delay Time Phase Error 7 Orthogonality Error3 Output Noise Output Series Resistance k tDEL ΦERR OE VNOISE RO Output −3 dB Cutoff Frequency3 Power Supply Rejection3 f−3dB PSRR Output Short-Circuit Current ISC Power-Up Time Max Unit 180 ±3 ±3 ±4 Degrees Degrees Degrees Degrees Degrees ±0.5 TA = −40°C to +125°C, GC = VDD TA = −40°C to +125°C, rotation frequency = 2000 rpm After end of line (EOL) calibration for offset voltage error and amplitude synchronism at TA = −40°C to +125°C (only 180° range) ±0.5 0.1 ±0.4 0.05 Degrees Degrees Degrees VAMP GC = VDD Sensitivity POWER SUPPLY Supply Voltage Quiescent Supply Current Typ 0 Single Point Calibration Angular Error 2, 3 OUTPUT PARAMETERS Amplitude GC = GND Min SEN VDD ISY tPWRUP TA = −40°C TA = 25°C TA = 125°C TA = −40°C TA = 25°C TA = 125°C VSIN and VCOS, normal operation VSIN or VCOS, broken bond wire detected GC = VDD GC = GND 63 41 21 56 52 38 7 75 53 33 77 72 57 93 3.75 3.75 3.75 +0.75 100 80 % VDD % VDD % VDD % VDD % VDD % VDD % VDD % VDD % VDD % VDD % peak µs Degrees Degrees µV rms Ω kΩ kHz dB 20 −18 52 mA mA mV/° −0.75 Rotation frequency = 30,000 rpm Rotation frequency = 30,000 rpm 2 0.8 BW = 80 kHz, RTO Normal operation, PD = GND PD = VDD Amplifier BW, CL = 10 pF Measured as output variation from VDD/2, VDD = 2.7 V to 5.5 V, RL = 200 kΩ to GND, GC = GND or VDD Short to GND per pin (VSIN, VCOS) Short to VDD per pin (VSIN, VCOS) α = 0° and 135°, TA = 25°C 500 50 0.05 PD = GND, GC = GND, no load PD = GND, GC = VDD PD = VDD, no load To 98% of desired output level after VDD was reached To 98% of desired output level after PD cycling Rev. 0 | Page 5 of 21 63 15 −15 2.7 3.5 4.5 5.5 6 6.5 12.5 150 V mA mA µA µs 100 µs Online Documentation Product Overview Design Resources Sample & Buy Discussion ADA4571 Parameter DIGITAL INPUTS Input Bias Current (GC) Input Bias Current (PD) Input Voltage (GC and PD) High Low TEMPERATURE SENSOR Error Over Temperature Temperature Voltage Range Temperature Coefficient VTEMP Output Voltage VTEMP Output Impedance VTEMP Load Capacitance VTEMP Short-Circuit Current LOAD CAPACITOR External Load Capacitance Data Sheet Symbol Test Conditions/Comments IB_GC For GC mode control pin, GC = GND For GC mode control pin, GC = VDD For PD pin, PD = GND For PD pin, PD = VDD IB_PD VIH VIL TERR TRANGE TCO ISC_VTEMP CL Min Typ Max Unit 30 30 µA µA µA µA 0.35 V V 3 3 1.4 5 TA = −40°C to +125°C 0 TA = 25°C Buffered output Optional load capacitance Short-circuit to VDD or GND 18 69 3.173 Between VSIN to GND and VCOS to GND; solder close to package 40 50 0 2 22 10 °C % VDD mV/V/°C % VDD Ω nF mA nF αUNCORR is the total mechanical angular error after arctan computation. This parameter is 100% production tested at 25°C and 150°C. This error includes all sources of error over temperature before calibration. Error components such as offset, amplitude synchronism, amplitude synchronism drift, thermal offset drift, phase error, hysteresis, orthogonality error, and noise are included. 2 αCAL is the total mechanical angular error after arctan computation. This error includes all sources of error over temperature after an initial offset (nulling) is performed at TA = 25°C. Error components such as amplitude synchronism drift, amplifier gain matching, thermal offset drift, phase error, hysteresis, orthogonality error, and noise are included. 3 Guaranteed through characterization. 4 αDYNAMIC is the total mechanical angular error after arctan computation. This parameter is 100% production tested. This error includes all sources of error over temperature after a continuous background calibration is performed to correct offset and amplitude synchronism errors. Error components such as phase error, hysteresis, orthogonality error, noise, and lifetime drift are included. 5 Angular speed <300 rpm. Limited to 180° rotation. The value is calculated only with the third and fifth harmonics of the spectrum of output signal amplitude by the ideal homogeneous field. 6 Peak-to-peak amplitude mismatch. k = 100 × VSIN/VCOS. 7 Rotation frequency dependent phase error, after offset correction, amplitude calibration, and arctan calculation. 1 Rev. 0 | Page 6 of 21 Product Overview Design Resources Online Documentation Discussion Sample & Buy Data Sheet ADA4571 ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE Table 4. Parameter Operating Temperature Storage Temperature Supply Voltage (VDD)1 Output Short-Circuit Duration to GND or VDD VTEMP Short-Circuit to GND or VDD ESD Human Body Model (HBM)2 Machine Model (MM)3 Charge Device Model (CDM)4 Rating −40°C to +150°C −65°C to +150°C −0.3 V to +6 V Indefinite Indefinite θJA is specified for the worst case conditions, that is, a device soldered in a circuit board for surface-mount packages. 4000 V 300 V 1250 V ESD CAUTION Table 5. Thermal Resistance Package Type 8-Lead SOIC GC or PD at VDD + 0.3 V. Applicable standard: JESD22-C101. 3 Applicable standard: JESD22-A115. 4 Applicable standard: ESDA/JEDEC JS-001-2011. 1 2 Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability. Rev. 0 | Page 7 of 21 θJA 120 Unit °C/W Product Overview Design Resources Online Documentation Discussion ADA4571 Data Sheet PIN CONFIGURATION AND DESCRIPTIONS 8 ADA4571 PD VDD TOP VIEW GND 3 (Not to Scale) 6 GND VSIN 4 7 5 VTEMP Figure 2. Pin Configuration Table 6. Pin Function Descriptions Mnemonic GC VCOS GND VSIN VTEMP GND VDD PD Description Gain Control Mode Enable Analog Cosine Output Ground Analog Sine Output Temperature Output Ground Supply Pin Power-Down Pin, Active High Rev. 0 | Page 8 of 21 12514-002 GC 1 VCOS 2 Pin No. 1 2 3 4 5 6 7 8 Sample & Buy Design Resources Online Documentation Product Overview Sample & Buy Discussion Data Sheet ADA4571 TYPICAL PERFORMANCE CHARACTERISTICS 40 5 –40°C +25°C +125°C +150°C 35 30 COUNT (%) OUTPUT AMPLITUDE (V) 4 3 2 25 20 15 10 1 5 360 270 180 90 RELATIVE MECHANICAL ANGLE (Degrees) 0 0 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 DYNAMIC ANGULAR ERROR (Degrees) Figure 3. Raw Output Waveforms, VDD = 5 V, GC = On, T = 25°C 12514-013 0 12514-010 0 Figure 6. Dynamic Angular Error, VDD = 5.5 V, GC = Off 0.2 35 –40°C +25°C +125°C +150°C 30 25 COUNT (%) ERROR (Degrees) 0.1 0 20 15 10 –0.1 0 90 180 270 360 MECHANICAL ANGLE (Degrees) 0 12514-011 –0.2 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 DYNAMIC ANGULAR ERROR (Degrees) Figure 4. Error Waveform After Offset Correction, VDD = 5 V, GC = On Figure 7. Dynamic Angular Error, VDD = 2.7 V, GC = On 40 35 –40°C +25°C +125°C +150°C 35 0 12514-014 5 –40°C +25°C +125°C +150°C 30 30 15 20 15 10 10 5 5 0 0 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 DYNAMIC ANGULAR ERROR (Degrees) 0.50 0 0 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 DYNAMIC ANGULAR ERROR (Degrees) Figure 5. Dynamic Angular Error, VDD = 5.5 V, GC = On Figure 8. Dynamic Angular Error, VDD = 2.7 V, GC = Off Rev. 0 | Page 9 of 21 0.50 12514-015 COUNT (%) 20 12514-012 COUNT (%) 25 25 Design Resources Online Documentation Product Overview Sample & Buy Discussion ADA4571 Data Sheet 40 35 –40°C +25°C +125°C +150°C 35 30 25 25 COUNT (%) 20 15 20 15 10 10 5 5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 UNCORRECTED ANGULAR ERROR (Degrees) 0 12514-016 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 UNCORRECTED ANGULAR ERROR (Degrees) Figure 9. Uncorrected Angular Error, VDD = 5.5 V, GC = On Figure 12. Uncorrected Angular Error, VDD = 2.7 V, GC = Off 40 1.2 –40°C +25°C +125°C +150°C 35 0 12514-019 COUNT (%) 30 0 –40°C +25°C +125°C +150°C 1.0 ERROR (Degrees) COUNT (%) 30 25 20 15 0.8 0.6 0.4 10 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 UNCORRECTED ANGULAR ERROR (Degrees) 0 –40 12514-017 0 Figure 10. Uncorrected Angular Error, VDD = 5.5 V, GC = Off 40 80 120 TEMPERATURE (°C) Figure 13. Single Point Calibration Angular Error, VDD = 5.5 V, GC = On 35 1.2 –40°C +25°C +125°C +150°C 30 0 12514-020 0.2 5 1.0 ERROR (Degrees) 20 15 0.8 0.6 0.4 10 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 UNCORRECTED ANGULAR ERROR (Degrees) Figure 11. Uncorrected Angular Error, VDD = 2.7 V, GC = On 0 –40 0 40 80 TEMPERATURE (°C) 120 12514-021 0.2 5 12514-018 COUNT (%) 25 Figure 14. Single Point Calibration Angular Error, VDD = 5.5 V, GC = Off Rev. 0 | Page 10 of 21 Design Resources Online Documentation Product Overview Sample & Buy Discussion ADA4571 5.8 1.0 5.6 0.8 5.4 0.6 5.2 0.4 5.0 0.2 4.8 0 –40 0 40 80 120 TEMPERATURE (°C) 4.6 –40 0 40 80 120 TEMPERATURE (°C) Figure 15. Single Point Calibration Angular Error, VDD = 2.7 V, GC = On Figure 18. Supply Current (ISY) vs. Temperature, VDD = 5 V 1.2 4.6 1.0 GC OFF (mA) GC ON (mA) 4.4 0.8 ISY (mA) 0.6 4.2 4.0 0.4 3.8 0.2 0 40 80 3.6 –40 12514-023 0 –40 120 TEMPERATURE (°C) 0 40 80 120 TEMPERATURE (°C) Figure 16. Single Point Calibration Angular Error, VDD = 2.7 V, GC = Off 12514-026 ERROR (Degrees) GC OFF (mA) GC ON (mA) 12514-025 ISY (mA) 1.2 12514-022 ERROR (Degrees) Data Sheet Figure 19. Supply Current (ISY) vs. Temperature, VDD = 3 V 7 10 5V 3V 8 IPD (µA) 5 6 4 4 3 2.7 3.1 3.5 3.9 4.3 4.7 5.1 VDD (V) 5.5 0 –40 0 40 80 120 TEMPERATURE (°C) Figure 20. Power-Down Current (IPD) vs. Temperature Figure 17. Supply Current (ISY) vs. Voltage (VDD), T = 25°C Rev. 0 | Page 11 of 21 12514-027 2 12514-024 ISY (mA) 6 Design Resources Online Documentation Product Overview Sample & Buy Discussion ADA4571 Data Sheet 100 100 90 90 80 80 60 50 40 30 60 50 40 30 20 20 10 10 40 80 120 0 –40 TEMPERATURE (°C) –0.1 ANGULAR ERROR DELAY (Degrees) 0 18 16 14 12 10 8 6 4 2 0 0.25 0.50 0.75 AMPLITUDE MISMATCH (%) 1.00 –0.3 –0.4 –0.5 –0.6 –0.7 –0.8 –1.0 300 12514-029 –0.25 120 –0.2 –0.9 –0.50 80 Figure 23. Output Voltage (VSIN and VCOS) Peak-to-Peak vs. Temperature (% VDD) 20 –0.75 40 TEMPERATURE (°C) Figure 21. VTEMP Output Voltage vs. Temperature 0 –1.00 0 ERROR –40°C ERROR +25°C ERROR +150°C 3000 RPM (Mechanical) Figure 22. Amplitude Synchronism (% k) Figure 24. Angular Error Delay vs. RPM (Mechanical) Rev. 0 | Page 12 of 21 30000 12514-031 0 12514-028 0 –40 COUNT (%) 70 12514-030 VOUT (V p-p %VDD) VTEMP (%VDD) 70 VOUT p-p GC OFF VOUT p-p GC ON Product Overview Design Resources Online Documentation Data Sheet Discussion Sample & Buy ADA4571 TERMINOLOGY Reference Position Error The reference position error is the absolute mounting position deviation of the sensor from its nominal placement. The reference position for Y = 0 μm is the straight connection line of Pin 2 and Pin 7. The X = 0 μm position is referred to the middle distance of the package top. The position accuracies are within a precision of ±0.05 mm (±50 μm) in both the X and Y direction. GC 1 8 PD VCOS 2 7 VDD GND 3 6 GND VSIN 4 5 VTEMP 12514-006 Reference Angle Error The reference angle error is the absolute mounting rotation deviation of the sensor from its nominal placement. Marking the position for angle Φ= 0° position is referred parallel to the straight connection line of Pin 2 and Pin 7. Figure 25. Bonding Arrangement and Sensor Alignment in Package Output Amplitude Synchronism Error The output amplitude matching error (k) is defined as the relationship between both output channel amplitudes at continuously rotating magnetic excitation of the MR sensor mathematically expressed as Uncorrected Angular Error The uncorrected angular error is defined as the maximum deviation from an ideal angle reading, when calculating the angle from VSIN and VCOS without offset calibration. Single Point Calibration Angular Error The single point calibration angular error is defined as the maximum deviation from an ideal angle reading, when calculating the angle from VSIN and VCOS after an initial calibration for offset voltage at TA = 25°C. Dynamic Angular Error The dynamic angular error is defined as the maximum deviation from an ideal angle reading, when calculating the angle from VSIN and VCOS while a continuous offset calibration is taken into account. Phase Error The phase error (ΦERR) is defined as the rotation frequency dependent error due to bandwidth limitation of the instrumentation amplifiers. VSIN and VCOS are impacted by the amplifier propagation delay, referred to the actual angle direction of the rotating magnetic field. The typical characteristics value can be used for a first-order compensation of this error on very high rotations per minute. For low rotational speed systems, this error component is negligible and no compensation is necessary. k = 100% × VSIN_P-P/VCOS_P-P Rev. 0 | Page 13 of 21 Product Overview Design Resources Online Documentation Sample & Buy Discussion ADA4571 Data Sheet THEORY OF OPERATION Electromagnetic interference (EMI) filters at the sensor outputs and between the first and second stages reject unwanted noise and interference from appearing in the signal band. The ADA4571 is an AMR sensor with integrated signal conditioning amplifiers and ADC drivers. The ADA4571 produces two analog outputs, sine and cosine, which indicate the angular position of the surrounding magnetic field. The architecture of the instrumentation amplifier consists of precision, low noise, zero drift amplifiers that feature a proprietary chopping technique. This chopping technique offers a low input offset voltage of 0.3 μV typical and an input offset voltage drift of 0.02 μV/°C typical. The zero drift design also features chopping ripple suppression circuitry, which removes glitches and other artifacts caused by chopping. The AMR sensing element is designed and manufactured by Sensitec GmbH. Figure 27 shows the sine channel, consisting of an AMR sensor element and the supporting functions for control, filtering, buffering, and signal amplification. A reference voltage that is proportional to the supply voltage is generated and it controls the supply voltage of the sensor bridges. For noise and electromagnetic compatibility (EMC) suppression purposes, the bridge supply is low-pass filtered. The bridge output voltages are amplified by a constant factor (G = 40, GC mode disabled) and buffered. The single-ended outputs are biased around a common-mode voltage of VDD/2 and are capable of driving the inputs of an external ADC referenced to the supply voltage. Offset voltage errors caused by common-mode voltage swings and power supply variations are also corrected by the chopping technique, resulting in a dc common-mode rejection ratio that is greater than 150 dB. The amplifiers feature low broadband noise of 22 nV/√Hz and no 1/f noise component. These features are ideal for amplification of the low level AMR bridge signals for high precision sensing applications. In addition, extensive diagnostics are integrated on-chip to self check sensor and IC conditions. VDD 1 2 8 ADA4571 7 3 TOP VIEW (Not to Scale) 6 4 5 12514-004 For optimum use of the ADC input range, the cosine and sine output voltages track the supply voltage ensuring a ratiometric configuration. To achieve high signal performance both output signals are carefully matched in both amplitude and phase. The amplifier bandwidth is sufficient to ensure low phase delay at maximum specified rotation speed. Figure 26. Direction of Homogeneous Magnetic Field for α = 0° VDD VDD + – 62.7pF + 3.3kΩ VTEMP – – AMR BRIDGE 20pF 50Ω VSIN + ADA4571 – 3.3kΩ VDD/2 Figure 27. Detailed Internal Diagram of the ADA4571 Sine Channel Rev. 0 | Page 14 of 21 12514-005 + 62.7pF Design Resources Online Documentation Product Overview Sample & Buy Discussion Data Sheet ADA4571 DIAGNOSTIC BAND 93% VDD VCOS VOFFSET V p-p LINEAR REGION 50% VDD DIAGNOSTIC BAND 0 90 180 270 360 MAGNETIC ANGLE, α (Degrees) Figure 28. Typical Output Waveforms; Sine and Cosine vs. Magnetic Angle Rev. 0 | Page 15 of 21 12514-003 VSIN 7% VDD Product Overview Design Resources Online Documentation Discussion ADA4571 Sample & Buy Data Sheet APPLICATIONS INFORMATION The integrated AMR sensor is designed for applications with a separate processing IC or electronic control unit (ECU) containing an ADC with references connected to the supply voltage. With the ADC input resolution related to VDD in the same way as the AMR sensor output, the system is inherently ratiometric and the signal dependency on supply voltage changes are minimized. To achieve maximum accuracy from the VTEMP output voltage, perform an initial calibration at a known, controlled temperature. Then, use the following equation to extract temperature information: TVTEMP ANGLE CALCULATION To calculate angle from the output of the AMR device, use the trigonometric function arctangent2. The arctangent2 function is a standard arctangent function with additional quadrant information to extend the output from the magnetic angle range of −90° to +90° to the magnetic angle range of −180° to +180°. Because of the sensing range of AMR technology, this calculated magnetic angle repeats over each pole of the magnet. For a simple dipole magnet, the following equation reports absolute angle over 180° mechanical: V arctan( SIN ) VCOS 2 – T T – VCAL VTEMP CAL CO V DD V DD TC VTEMP where: TVTEMP is the calculated temperature (°C) from the VTEMP output voltage. VTEMP is the VTEMP output voltage during operation. VDD is the supply voltage. VCAL is the VTEMP output voltage during calibration at a controlled temperature. TCAL is the controlled temperature during calibration. TCO is the temperature coefficient of the internal circuit; see the Specifications section for the exact value. Gain Control Mode CONNECTION TO ECU Because of the limited driving capability of the ADA4571 output, minimize the length of printed circuit board (PCB) traces between the ADA4571 and other IC. Shielding of the signal lines is recommended. Match the load capacitors and resistors for best angular accuracy. Add bandwidth limitation filters related to the sampling frequency of the system in front of the ADC inputs to reduce noise bandwidth. In Figure 29, the load resistors on VCOS and VSIN are representing the input load of the filter and the ADC. The processor may be used for arctan and offset calculations, offset storage, and additional calibration. VTEMP Output Pin A proportional to absolute temperature circuit provides a voltage output at the VTEMP pin for temperature monitoring or temperature calibration purposes. The output voltage is ratiometric to the supply voltage enabling the interface with an ADC that uses the supply voltage to generate the reference voltage. This pin must be left open when not in use. Gain control (GC) enable mode can be activated by switching the GC pin to the VDD pin. In this mode, the AMR bridge sensor amplitude outputs are compensated to reduce temperature variation. This results in higher and controlled output voltage levels, boosting system dynamic range and easing the system design task. If the GC pin is left floating, a weak pull-up resistor ensures that the GC mode is enabled as a default condition. The GC mode can also be used as a sensor self diagnostic by comparing the sine and cosine amplitude outputs when enabled and disabled, such as radius check. In the event that the radius does not change, it indicates a gross failure in the IC. Power-Down Mode Power-down mode can be activated by switching the PD pin to the VDD pin. Within this mode, the device shuts down and its output pins are set to high impedance to avoid current consumption across the load resistors. The VTEMP output is connected to ground through a pull-down resistor. Power-down mode can be entered with GC = VDD or GC = GND. An internal pull-down resistor ensures that the device remains active if the PD pin is left floating. Rev. 0 | Page 16 of 21 Design Resources Online Documentation Product Overview Discussion Sample & Buy Data Sheet ADA4571 VDD RLO4 CLO4 VDD TEMPERATURE SENSOR BRIDGE DRIVER EMI FILTER AMR BRIDGE SENSORS BIAS EMI FILTER GND + G = 40 DRIVER – GC VDD VSIN Σ-Δ ADC RLO1 OSCILLATOR G = 40 MICROPROCESSOR DRIVER Σ-Δ ADC VCOS RLO2 GND CLO1 FAULT DETECTION + – VTEMP CLO2 PD RLO3 CLO3 12514-007 ADA4571 Figure 29. Typical Application Diagram with Separate Processor and Data Conversion Offset of Signal Outputs Power Consumption Worst case quiescent power occurs when the supply current runs at its specified maximum of 7 mA and the ADA4571 is run at the maximum VDD of 5.5 V, giving a worst case quiescent power of 38.5 mW. The power consumption is dependent on VDD, temperature, load resistance (RL), load capacitance (CL), and frequency of the rotating magnetic field. It is recommended to refer RL and CL to ground. The output voltages are protected against short circuit to the VDD pin or ground by current limitation within the given time duration. Placing the device 180° rotated into the socket may lead to damages if the supply current is not limited to 100 mA. The single-ended output signals are referenced to VDD/2 generated internally on-chip. Offsets originate from matching inaccuracies and other imperfections during the production process. For tight tolerances, it is required to match the external loads for VSIN and VCOS to each other. For ESD and EMC protection, the outputs contain a series resistance of 50 Ω. The influence of this series resistance is minimized with a large output load resistance. Signal Dependence on Air Gap Distance The IC measures the direction of the external magnetic field within its x-y plane. The result is widely independent of the field strength as long as it is above the specified minimum value of 25 kA/m. Within a homogeneous field in x-y direction, the result is independent of its placement in z direction (air gap). The nominal z distance of the internal x-y plane to the top surface of the plastic package is 0.400 mm. Rev. 0 | Page 17 of 21 Product Overview Design Resources Online Documentation Sample & Buy Discussion ADA4571 Data Sheet MECHANICAL TOLERANCES DIAGRAMS 5.00 4.90 4.80 SENSING ELEMENT CENTER B 5 8 NOTE 4 4.00 3.90 3.80 A 2.50 2.45 2.40 0.50 C B 2° MAX 1 2.00 1.95 1.90 3.10 3.00 2.90 4 NOTE 2 LEAD TIPS 6.20 6.00 5.80 0.854 0.25 C A NOTES 3, 6, 7 0.487 0.437 0.387 NOTES 5, 6 0.10 C 1.27 C SEATING PLANE 0.25 M C A B NOTES 1. DIMENSIONS ARE IN MILLIMETERS. 2. MAXIMUM SENSOR ROTATION. 3. THIS DIMENSION AND TRUE POSITION SPECIFY THE LOCATION OF THE CENTER OF THE SENSING ELEMENT WITH RESPECT TO THE CENTER OF THE PACKAGE. THE CENTER OF THE SENSING ELEMENT IS ALIGNED WITH THE EDGES OF LEAD 2 AND LEAD 7. 4. THE CENTER OF THE SENSING ELEMENT IS ALIGNED WITH THE CENTER LINE OF THE PACKAGE (DATUM B). 5. THE LEAD WIDTH DIMENSION IS TOLERANCED MORE TIGHTLY THAN ON THE R8 PACKAGE OUTLINE DRAWING. THIS DIMENSION IS MEASURED AT THE FOOT OF THE LEAD (NO FLASH, BURRS). 6. DOES NOT INCLUDE MOLD FLASH, DAMBAR PROTRUSIONS, OR BURRS. 7. MOLD BODY WIDTH AND LENGTH DIMENSIONS DO NOT INCLUDE MOLD FLASH, OFFSETS, OR MOLD GATE PROTRUSIONS. 8. REFER TO THE R8 PACKAGE OUTLINE DRAWING FOR DIMENSIONS NOT SHOWN HERE. Figure 30. Mechanical Drawing of the ADA4571 AMR SENSING ELEMENT 1.400 1.250 1.100 0.10 C C SEATING PLANE Figure 31. Cross Sectional View of the ADA4571 Rev. 0 | Page 18 of 21 12514-035 0.475 0.400 0.325 12514-034 ALL LEADS Design Resources Online Documentation Product Overview Sample & Buy Discussion Data Sheet ADA4571 V RAD = (V SIN − V DD 2 V ) + (VCOS − DD ) 2 2 2 Figure 32 shows the allowable radius values when GC mode is enabled and Figure 33 shows the allowable radius values when GC mode is disabled. The maximum and minimum VRAD values are calculated based on the allowable amplitude range for VSIN and VCOS, over the entire operating temperature of the device as specified in the Specifications section. This range is represented by the shaded region in Figure 32 and Figure 33. VRAD VCOS VCOS GC ON Figure 32. GC On Radius Values 12514-101 VCOS MAGNITUDE (%VDD) VRAD VCOS VCOS VCOS MAGNITUDE (%VDD) GC OFF Figure 33. GC Off Radius Values Monitoring of the VTEMP pin can allow an even tighter range for radius length at the known temperature. See the Specifications section and the Typical Performance Characteristics section for exact values and output amplitude specifications at each temperature. Broken Bond Wire Detection The ADA4571 includes circuitry to detect broken bond wire conditions between the AMR sensor and the instrumentation amplifier. The detection circuitry consists of current sources and window comparators placed on the signal connections between the AMR sensor and the ASIC. The purpose of the current sources is to pull the signal node outside of the normal operating region in the event of an open bond wire between the AMR sensor and the ASIC. The purpose of the window comparators is to detect when the signal from the AMR sensor is outside of the normal operating region. When the comparators detect that the signal nodes are outside the normal operating region, the circuit pulls the VSIN and/or VCOS node to ground to indicate the fault to the host controller. +150°C +125°C +25°C –40°C VSIN 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 VSIN 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 VSIN MAGNITUDE (%VDD) Typical VRAD values for −40°C, +25°C, +125°C, and +150°C are indicated as well. +150°C +125°C +25°C –40°C 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 It is important to perform offset calibration before calculating the radius. VSIN 12514-100 The VSIN and VCOS outputs can be used to calculate a radius value. These outputs have a fixed 90° phase relationship and therefore the calculated radius value remains in a predictable, predetermined range that varies with the temperature of the device independent of the current magnetic field direction. This radius, VRAD, can be used to validate the VSIN and VCOS readings in the ECU. When the calculated radius is no longer within the acceptable bounds, a fault may occur in the system. To calculate radius, use the following formula: VSIN MAGNITUDE (%VDD) Radius Calculation 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 VSIN DIAGNOSTICS In addition to the active circuitry, there are applications recommendations, such as the utilization of pull-up and pulldown resistors, which detect broken bond wires by pulling nodes outside of the defined operating regions. A broken bond wire at VTEMP, VCOS, and VSIN interrupts the corresponding outputs. To ensure that the output enters into a known state if there is a broken bond wire on these pins, connect a 200 kΩ pull-down resistor at these pins. Pulling these nodes outside of the normal operating region signals a fault to the host controller. Rev. 0 | Page 19 of 21 Design Resources Online Documentation Product Overview Discussion Sample & Buy ADA4571 Data Sheet Short-Circuit Condition to GND or VDD Short-Circuit Between Sine and Cosine Sensor Outputs In the event of a short-circuit condition, the output voltages are pulled to the GND or VDD pin. In the event of a short-circuit between sensor outputs, the IC output voltages are tied to the output common-mode voltage. A gross angular error is detected in the microcontroller. 100% SHORT-CIRCUIT DIAGNOSTIC BAND (HIGH) OUTPUT LEVEL 93% 7% SHORT-CIRCUIT DIAGNOSTIC BAND (LOW) 0% 12514-009 LINEAR REGION Figure 34. Output Span Classification During Short-Circuit Diagnostic Condition Table 7. Diagnostic Cases Fault Description Broken Bond Wire Between the Internal MR Sensor and the ASIC Broken Bond Wire at the PD Pin Broken Bond Wire at the GC Pin Output Short-Circuit to GND Output Short-Circuit to VDD Output Conditions Broken bond wire detection is activated; the broken channel(s), VSIN or VCOS, are pulled to ground Device remains functional Gain control is activated Shorted channel is pulled to ground Shorted channel is pulled to VDD Rev. 0 | Page 20 of 21 Alert Diagnostic region violation No alert Possible change in output amplitude Diagnostic region violation Diagnostic region violation Product Overview Design Resources Online Documentation Discussion Data Sheet Sample & Buy ADA4571 OUTLINE DIMENSIONS 5.00 (0.1968) 4.80 (0.1890) 8 1 5 6.20 (0.2441) 5.80 (0.2284) 4 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040) COPLANARITY 0.10 SEATING PLANE 1.75 (0.0688) 1.35 (0.0532) 0.51 (0.0201) 0.31 (0.0122) 0.50 (0.0196) 0.25 (0.0099) 45° 8° 0° 0.25 (0.0098) 0.17 (0.0067) 1.27 (0.0500) 0.40 (0.0157) COMPLIANT TO JEDEC STANDARDS MS-012-AA CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN. 012407-A 4.00 (0.1574) 3.80 (0.1497) Figure 35. 8-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-8) Dimensions shown in millimeters and (inches) ORDERING GUIDE Model1, 2 ADA4571WHRZ-R7 ADA4571BRZ ADA4571BRZ-RL ADA4571BRZ-R7 1 2 Temperature Range −40°C to +150°C −40°C to +125°C −40°C to +125°C −40°C to +125°C Package Description 8-Lead SOIC_N, 7” Tape and Reel 8-Lead SOIC_N 8-Lead SOIC_N, 13” Tape and Reel 8-Lead SOIC_N, 7” Tape and Reel Package Option R-8 R-8 R-8 R-8 Z = RoHS Compliant Part. W = Qualified for Automotive Applications. AUTOMOTIVE PRODUCTS The ADA4571WHRZ model is available with controlled manufacturing to support the quality and reliability requirements of automotive applications. Note that this automotive model may have specifications that differ from the commercial models; therefore, designers should review the Specifications section of this data sheet carefully. Only the automotive grade products shown are available for use in automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to obtain the specific Automotive Reliability reports for these models. ©2014 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D12514-0-9/14(0) Rev. 0 | Page 21 of 21