MA302GQ-P

MagAlpha MA302 12-Bit, Digital, Contactless Angle Sensor with ABZ & UVW Incremental Outputs DESCRIPTION FEATURES The MA302 detects the absolute angular position of a permanent magnet, typically a diametrically magnetized cylinder on a rotating shaft. Fast data acquisition and processing provide accurate angle measurement at speeds from 0 to 60,000 rpm.    The MA302 supports a wide range of magnetic field strengths and spatial configurations. Both end-of-shaft and off-axis (side-shaft mounting) configurations are supported.    The MA302 features magnetic field strength detection with programmable thresholds to allow sensing of the magnet position relative to the sensor for creation of functions such as sensing of axial movements or for diagnostics.    On-chip non-volatile memory provides storage for configuration parameters, including the reference zero angle position, ABZ encoder settings, UVW pole pair emulation settings, and magnetic field detection thresholds.     12-Bit Resolution Absolute Angle Encoder Contactless Sensing for Long Life SPI Serial Interface for Digital Angle Readout and Chip Configuration Incremental 10-Bit ABZ Quadrature Encoder Interface with Programmable Pulses Per Turn from 1 to 256 UVW Interface with 1 to 8 Pole Pair Emulation Programmable Magnetic Field Strength Detection for Diagnostic Checks 3.3V, 12mA Supply -40°C to +125°C Operating Temperature Available in a QFN-16 (3mmx3mm) Package APPLICATIONS Brushless DC Motor Servo Drives Motor Commutation Motor Speed and Position Control Robotics All MPS parts are lead-free, halogen-free, and adhere to the RoHS directive. For MPS green status, please visit the MPS website under Quality Assurance. “MPS” and “The Future of Analog IC Technology” are registered trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 1 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS ORDERING INFORMATION Part Number* MA302GQ Package QFN-16 (3mmx3mm) Top Marking See Below * For Tape & Reel, add suffix –Z (e.g. MA302GQ–Z) TOP MARKING AWD: Product code of MA302GQ Y: Year code LLL: Lot number PACKAGE REFERENCE TOP VIEW QFN-16 (3mmx3mm) MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 2 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance (3) Supply voltage ............................ -0.5V to +4.6V Input pin voltage (VI) ................... -0.5V to +6.0V Output pin voltage (VO) ............... -0.5V to +4.6V Continuous power dissipation (TA = +25°C) (2) ..................................................................2.0W Junction temperature ............................... 125°C Lead temperature .................................... 260°C Storage temperature .................. -65°C to 150°C QFN-16 (3mmx3mm) ............ 50 ....... 12 ... °C/W MA302 Rev. 1.1 2/7/2020 θJA θJC NOTES: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the maximum junction temperature TJ (MAX), the junction-toambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by PD (MAX) = (TJ (MAX)-TA)/θJA. 3) Measured on JESD51-7, 4-layer PCB. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 3 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS ELECTRICAL CHARACTERISTICS Parameter Symbol Condition Recommended Operating Conditions Min Typ Max Units Supply voltage VDD 3.0 3.3 3.6 V Supply current IDD 10.2 11.7 13.8 mA Operating temperature Applied magnetic field Top B 125 °C mT MA302 Rev. 1.1 2/7/2020 From -40°C to +125°C -40 30 60 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 4 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS GENERAL CHARACTERISTICS VDD = 3.3V, 45mT < B < 100mT, Temp = -40°C to +125°C, unless otherwise noted. Parameter Absolute Output – Serial Symbol Effective resolution Condition Min Typ Max Units 3σ deviation of the noise distribution 11.0 11.8 12.8 bit 0.01 850 14 0.02 980 0.03 1100 14 deg kHz bit 12 ms 10 µs Noise rms Refresh rate Data output length Response Time Power-up time (4) Constant speed propagation delay Latency (5) Filter cutoff frequency (4) Accuracy 8 Fcutoff At room temperature over the full field range Over the full temperature range and field range INL at 25°C INL between -40°C to +125°C (5) Output Drift Temperature induced drift at room temperature (5) From 25°C to 85°C From 25°C to 125°C Temperature induced variation (5) 390 Hz 0.7 deg 1.1 deg 0.015 0.04 deg/°C 0.5 1.0 1.2 2.1 deg deg 0.3 deg/mT deg/V Magnetic field induced (5) Voltage supply induced (5) Incremental Output – ABZ 0.005 ABZ update rate Resolution - edges per turn Pulses per channel per turn ABZ hysteresis (5) 16 Systematic jitter PPT+1 H (5) Random jitter (3σ) Overall ABZ jitter (5) Incremental Output – UVW Cycle per turn UVW hysteresis (5) UVW jitter (3σ) (5) MA302 Rev. 1.1 2/7/2020 NPP H Programmable Programmable 4 1 MHz 1024 256 0.7 deg For PPT = 255, between 0 and 100krpm, up to 60mT 13 % For PPT = 127, between 0 and 100krpm 7 % For PPT = 255, between 0 and 100krpm 5.5 % For PPT = 127, between 0 and 100krpm 2.8 % Up to 60mT 0.3 deg 8 0.7 0.3 deg deg 1 0.1 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 5 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS GENERAL CHARACTERISTICS (continued) VDD = 3.3V, 45mT < B < 100mT, Temp = -40°C to +125°C, unless otherwise noted. Parameter Symbol Condition Magnetic Field Detection Thresholds Accuracy (5) Hysteresis (5) Temperature drift (5) Digital I/O Input low voltage voltage (5) Output high voltage (5) Pull-down resistor Rising edge slew rate (4) Falling edge slew rate (4) Typ Max 5 6 -600 MagHys Input high voltage Output low Min 2.5 -0.3 Units mT mT ppm/°C VIH VIL VOL VOH RPD IOL = 4mA TR CL = 50pF 0.7 V/ns TF CL = 50pF 0.7 V/ns IOH = 4mA 2.4 43 5.5 0.8 0.4 V V V V 55 97 kΩ NOTES: 4) Guaranteed by design. 5) Guaranteed by characteristic test. MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 6 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS TYPICAL CHARACTERISTICS VDD = 3.3V, Temp = 25°C, unless otherwise noted. ABZ Jitter at PPT = 255 Noise Spectrum at 50mT Filter Transfer Function 5 6 FILTER TRANSFER FUNCTION (dB) 0.01 RANDOM JITTER (%) 1/2 NOISE DENSITY (deg/Hz ) 5 4 3 0.001 0 -3 dB -5 -10 -15 2 -20 0.0001 1 0.1 1 10 100 1000 10 4 10 10 10 5 100 1000 10 4 10 100 1000 10 4 10 5 5 f (Hz) FREQUENCY (Hz) ROTATION SPEED (rpm) Non-Linearity (INL and harmonics) Error Curves at 50mT Effective Resolution (3σ) 1.5 12 2 11.5 -45°C 0 -1 EFFECTIVE RESOLUTION (bit) NON-LINEARITY (deg) ERROR (deg) INL 25°C 125°C 1 1 H1 0.5 H2 11 10.5 10 9.5 9 8.5 -2 8 0 0 50 100 150 200 250 300 350 ANGLE (deg) 0 20 40 60 MAGNETIC FIELD (T) 80 100 0 20 40 60 80 100 120 MAGNETIC FIELD (mT) Current Consumption at VDD = 3.3V 12 SUPPLY CURRENT (mA) 11.5 11 10.5 10 -50 0 50 100 150 TEMPERATURE (°C) MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 7 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS PIN FUNCTIONS Package Pin # Name 1 2 V A 3 4 5 6 Z MOSI CS B 7 MISO 8 9 GND W Incremental output. Data in (SPI). MOSI has an internal pull-down resistor. Chip select (SPI). CS has an internal pull-up resistor. Incremental output. Data out (SPI). MISO has an internal pull-down resistor that is enabled at a high impedance state. Supply ground. Motor commutation output. 10 11 12 13 14 15 16 TEST MGL SCLK VDD NC U MGH Connect to ground. Digital output indicating field strength below MGLT level. Clock (SPI). SCLK has an internal pull-down resistor. Supply 3.3V. No connection. Leave NC unconnected. Motor commutation output. Digital output indicating field strength above MGHT level. MA302 Rev. 1.1 2/7/2020 Description Motor commutation output. Incremental output. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 8 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS BLOCK DIAGRAM Figure 1: Functional Block Diagram MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 9 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS OPERATION Sensor Front-End The magnetic field is detected with integrated Hall devices located in the center of the package. The angle is measured using the SpinaxisTM method, which directly digitizes the direction of the field without complex arctangent computation or feedback loop-based circuits (interpolators). The SpinaxisTM method is based on phase detection and generates a sinusoidal signal with a phase that represents the angle of the magnetic field. The angle is then obtained by a time-to-digital converter, which measures the time between the zero crossing of the sinusoidal signal and the edge of a constant waveform (see Figure 2). The time-to-digital is output from the front-end to the digital conditioning block. Sensor – Magnet Mounting The sensitive volume of the MA302 is confined in a region less than 100µm wide and has multiple integrated Hall devices. This volume is located both horizontally and vertically within 50µm of the center of the QFN package. The sensor detects the angle of the magnetic field projected in a plane parallel to the package’s upper surface. This means that the only relevant magnetic field is the in-plane component (X and Y components) in the middle point of the package. By default, when looking at the top of the package, the angle increases when the magnetic field rotates clockwise. Figure 3 shows the zero angle of the unprogrammed sensor, where the cross indicates the sensitive point. Both the rotation direction and the zero angle can be programmed. Top: Sine Waveform Bottom: Clock of Time-to-Digital Converter Figure 2: Phase Detection Method The output of the front-end delivers a digital number proportional to the angle of the magnetic field at the rate of 1MHz in a straightforward and open-loop manner. Digital Filtering The front-end signal is further treated to achieve the final effective resolution. This treatment does not add any latency in steady conditions. The filter transfer function can be calculated with Equation (1): H ( s)  1  2s (1  s) 2 (1) Where τ is the filter time constant, related to the cutoff frequency by τ = 0.38/Fcutoff. See the General Characteristics table on page 5 for the value of Fcutoff. MA302 Rev. 1.1 2/7/2020 Figure 3: Detection Point and Default Positive Direction This type of detection provides flexibility for the design of an angular encoder. The sensor only requires the magnetic vector to lie essentially within the sensor plane with a field amplitude of at least 30mT. Note that the MA302 can work with fields smaller than 30mT, but the linearity and resolution performance may deviate from the specifications. The most straightforward mounting method is to place the MA302 sensor on the rotation axis of a permanent magnet (i.e.: a diametrically magnetized cylinder) (see Figure 4). A typical magnet is a Neodymium alloy (N35) cylinder with dimensions Ø5x3mm inserted into an aluminum shaft with an air gap between the magnet and the sensor (surface of package) of 1.5mm. For good linearity, the sensor is positioned with a precision of 0.5mm. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 10 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS Generally, the MagAlpha works fine with or without the exposed pad connected to anything. For optimum conditions (electrically, thermally, and mechanically), it is recommended that the exposed pad be connected to ground. Figure 4: End-of-Shaft Mounting If the end-of-shaft position is not available, the sensor can be positioned away from the rotation axis of a cylinder or ring magnet (see Figure 5). In this case, the magnetic field angle is no longer directly proportional to the mechanical angle. The MA302 can be adjusted to compensate for this effect and recover the linear relation between the mechanical angle and the sensor output. With multiple pole pair magnets, the MA302 indicates multiple rotations for each mechanical turn. Figure 5: Side-Shaft Mounting Electrical Mounting and Power Supply Decoupling It is recommended to place a 1µF decoupling capacitor close to the sensor with a low impedance path to GND (see Figure 6). Serial Interface The sensor supports the SPI serial interface for angle reading and register programming. SPI SPI is a 4-wire, synchronous, serial communication interface. The MagAlpha supports SPI Mode 3 and Mode 0 (see Table 1 and Table 2). The SPI Mode (0 or 3) is detected automatically by the sensor and therefore does not require any action from the user. The maximum clock rate supported on SPI is 25MHz. There is no minimum clock rate. Note that real life data rates depend on PCB layout quality and signal trace length. See Figure 7, Figure 8, and Table 3 for SPI timing. All commands to the MagAlpha (whether for writing or reading register content) must be transferred through the SPI MOSI pin and must be 16 bits long. See the SPI Communication section on page 13 for details. Table 1: SPI Specification SCLK idle state Data capture Data transmission CS idle state Data order Mode 0 Mode 3 Low High On SCLK rising edge On SCLK falling edge High MSB first Table 2: SPI Standard CPOL CPHA Data order (DORD) Mode 0 Mode 3 0 1 0 1 0 (MSB first) Figure 6: Connection for Supply Decoupling MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 11 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS tcsL CS tsclk tsclkL tsclkH tcsH tMISO tMISO tidleAngle tidleReg tnvm SCLK tMISO MISO hi-Z MOSI MSB X LSB MSB hi-Z MSB X LSB MSB tMOSI Figure 7: SPI Timing Diagram tidleAngle tidleAngle tidleAngle tidleReg tidleReg tidleAngle tnvm tidleReg CS MISO Angle Angle Angle Angle Reg Value Angle Angle Reg Value Angle MOSI 0 0 0 Read Reg Cmd 0 0 Write Reg Cmd 0 0 Figure 8: Minimum Idle Time Table 3: SPI Timing Parameter (6) Description Min Max tidleAngle Idle time between two subsequent angle transmissions 150 ns tidleReg Idle time before and after a register readout 750 ns tnvm Idle time between a write command and a register readout (delay necessary for non-volatile memory update) 20 ms tcsL Time between CS falling edge and SCLK falling edge 80 ns tsclk SCLK period 40 ns tsclkL Low level of SCLK signal 20 ns tsclkH High level of SCLK signal 20 ns tcsH Time between SCLK rising edge and CS rising edge 25 ns tMISO SCLK setting edge to data output valid tMOSI Data input valid to SCLK reading edge 15 15 Unit ns ns NOTE: 6) All values are guaranteed by design. MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 12 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS SPI Communication The sensor supports three types of SPI operation:    Read angle Read configuration register Write configuration register Angle reading can be therefore optimized without any loss of information by reducing the number of clock counts. In the case of a 12-bit data output length, only 12 clock counts are required to get the full sensor resolution. MSB Each operation has a specific frame structure described below. SPI Read Angle Every 1µs, new data is transferred into the output buffer. The master device triggers the reading by pulling CS low. When a trigger event is detected, the data remains in the output buffer until the CS signal is de-asserted (see Table 4). LSB MISO Angle(15:4) MOSI 0 If less resolution is needed, the angle can be read by sending even fewer clock counts (since MSB is first). In case of fast reading, the MagAlpha keeps sending the same data until the data is refreshed (see the refresh rate in the General Characteristics table). Table 4: Sensor Data Timing Event CS falling edge CS rising edge Action Start reading and freeze output buffer Release of the output buffer See Figure 9 for a diagram of a full SPI angle reading. See Figure 10 for a diagram of a partial SPI angle reading. A full angle reading requires 16 clock pulses. The sensor MISO line returns: MSB LSB MISO Angle(15:0) MOSI 0 Figure 9: Diagram of a Full 16-Bit SPI Angle Reading The MagAlpha family has sensors with different features and levels of resolution. Check the data output length in the General Characteristics table on page 5 for the number of useful bits delivered at the serial output. If the data length is smaller than 16, the rest of bits sent are zeros. For example, a data output length of 12 bits means that the serial output delivers a 12-bit angle value with four bits of zeros padded at the end (MISO state remains zero). If the master sends 16 clock counts, the MagApha replies with: MSB MISO MOSI MA302 Rev. 1.1 2/7/2020 LSB Angle(15:4) 0 0 0 0 0 Figure 10: Diagram of a Partial 8-Bit SPI Angle Reading SPI Read Register A read register operation is constituted of two 16bit frames. The first frame sends a read request which contains the 3-bit read command (010) followed by the 5-bit register address. The last eight bits of the frame must be all set to zero. The second frame returns the 8-bit register value (MSB byte). www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 13 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS The first 16-bit SPI frame (read request) is: MSB MISO MOSI LSB Angle(15:0) command reg. address 0 1 0 A4 A3 A2 A1 A0 For example, to get the value of the magnetic level high and low flags (MGH and MGL). Read register 27 (bit 6, bit 7) by sending the following first frame: MSB 0 0 0 0 0 0 0 0 MISO The second 16-bit SPI frame (response) is: reg. value MISO V7 V6 V5 V4 V3 V2 V1 V0 MOSI 0 0 0 0 0 0 0 0 MSB MOSI LSB 0 See Figure 11 for a complete transmission overview. LSB Angle(15:0) command 0 1 0 reg. address 1 1 0 1 1 0 0 0 0 0 0 0 0 In the second frame, the MagAlpha replies: reg. value MISO MGH MGL X X X X X X 0 0 0 0 0 0 0 0 MSB MOSI LSB 0 See Figure 12 for a complete example overview. Figure 11: Two 16-Bit Frames Read Register Operation Figure 12: Example Read Magnetic Level Flags High and Low (MGH, MGH) on Register 27, Bit 7 to Bit 6 MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 14 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS SPI Write Register Table 5 shows the programmable 8-bit registers. Data written to these registers are stored in the on-chip non-volatile memory and reloaded automatically during power on. The factory default register values are shown in Table 6. A write register operation is constituted of two 16-bit frames. The first frame sends a write request which contains the 3-bit write command (100) followed by the 5-bit register address and the 8-bit value (MSB first). The second frame returns the newly written register value (acknowledge). The on-chip memory is guaranteed to endure 1,000 write cycles at 25°C. It is important to wait 20ms between the first and the second frame. This is the time taken to write the non-volatile memory. Failure to implement this wait period results in the register’s previous value being read. Note that this delay is only required after a write request. A read register request and read angle do not require this wait time. The second 16-bit SPI frame (response) is: reg. value MISO V7 V6 V5 V4 V3 V2 V1 V0 MSB LSB MOSI 0 The read-back register content can be used to verify the register programming. See Figure 13 for a complete transmission overview. For example, to set the value of the output rotation direction (RD) to counterclockwise (high), write register 9 by sending the following first frame: MSB MISO MOSI LSB Angle(15:0) command 1 0 0 reg. address 0 1 0 0 1 reg. value 1 0 0 0 0 0 0 0 Send the second frame after a 20ms wait time. If the register is correctly written, the reply is: reg. value MISO 1 0 0 0 0 0 0 0 The first 16-bit SPI frame (write request) is: MSB 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 MSB LSB MISO Angle(15:0) MOSI command reg. address reg. value 1 0 0 A4 A3 A2 A1 A0 V7 V6 V5 V4 V3 V2 V1 V0 MOSI LSB 0 See Figure 14 for a complete example. Figure 13: Overview of Two 16-Bit Frames Write Register Operation MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 15 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS Figure 14: Example Write Output Rotation Direction (RD) to Counterclockwise (High), on Register 9, Bit 7 MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 16 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS REGISTER MAP Table 5: Register Map Bit 7 MSB No Hex Bin Bit 6 0 0x0 00000 Z(7:0) 1 0x1 00001 Z(15:8) 2 0x2 00010 BCT(7:0) 3 0x3 00011 4 0x4 00100 5 0x5 00101 6 0x6 00110 MGLT(2:0) 7 0x7 00111 NPP(2:0) 9 0x9 01001 RD - 27 0x1B 11011 MGH MGL - - Bit 5 - Bit 4 - PPT(1:0) - Bit 3 Bit 2 Bit 1 Bit 0 LSB - ETY ETX - - - - ILIP(3:0) - PPT(7:2) MGHT(2:0) - - - - - - - - - - - MG1L MG2L - - Table 6: Factory Default Values No Hex Bin Bit 7 MSB Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 LSB 0 0x0 00000 0 0 0 0 0 0 0 0 1 0x1 00001 0 0 0 0 0 0 0 0 2 0x2 00010 0 0 0 0 0 0 0 0 3 0x3 00011 0 0 0 0 0 0 0 0 4 0x4 00100 1 1 0 0 0 0 0 0 5 0x5 00101 0 0 1 1 1 1 1 1 6 0x6 00110 0 0 0 1 1 1 0 0 7 0x7 00111 0 0 0 0 0 0 0 0 9 0x9 01001 0 0 0 0 0 0 0 0 MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 17 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS Table 7: Programming Parameters Parameters Symbol Number of Bits Zero setting Bias current trimming Z 16 BCT 8 Enable trimming X ETX 1 Enable trimming Y ETY 1 Pulses per turn PPT 8 ILIP 4 Parametrization of the ABZ index pulse. Fig. 23 MGHT 3 Sets the field strength high threshold. 14 MGLT 3 Sets the field strength low threshold. 14 NPP 3 RD 1 Index length / index position Magnetic field high threshold Magnetic field low threshold Number of pole pairs Rotation direction MA302 Rev. 1.1 2/7/2020 Description See Table Sets the zero position. For side-shaft configuration: reduces the bias current of the X or Y Hall device. Biased current trimmed in the X-direction Hall device. Biased current trimmed in the Y-direction Hall device. Number of pulses per turn of the ABZ output. 8 UVW cycles per turn for motor commutation. Determines the sensor positive direction. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 11 12 12 15 18 10 18 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS REGISTER SETTINGS Zero Setting The zero position of the MagAlpha (a0) can be programmed with 16 bits of resolution. The angle streamed out by the MagAlpha (aout) is given by Equation (2): aout  araw  a0 (2) Where araw is the raw angle provided by the MagAlpha front end. The parameter Z(15:0), which is zero by default, is the complementary angle of the zero setting. In decimals, it can be written as shown in Equation (3): a0  216  Z (15 : 0) (3) Table 8: Zero Setting Parameter Zero pos. a0 (16-bit dec) 65536 65535 65534 … 2 1 0 1 2 … 65534 65535 Zero pos. a0 (deg) 360.000 359.995 359.989 … 0.011 0.005 20 deg 16 2  61895 360 deg RD Positive Direction 0 1 Clockwise (CW) Counterclockwise (CCW) k  Brad / Btan Example To set the zero position to 20 degrees, the Z(15:0) parameter shall be equal to the complementary angle and can be calculated with Equation (4): Z (15 : 0)  216  Table 10: Rotation Direction Parameter BCT Settings (Bias Current Trimming) Side-Shaft When the MA302 is mounted on the side of the magnet, the relation between the field angle and the mechanical angle is no longer directly linear. This effect is related to the fact that the tangential magnetic field is usually smaller than the radial field. Define the field ratio k with Equation (5): Table 8 shows the zero setting parameter. Z(15:0) Figure 15: Positive Rotation Direction of the Magnetic Field (5) Where Brad is the maximum radial magnetic field, and Btan is the maximum tangential magnetic field (see Figure 16). (4) In binary, it is written as 1111 0001 1100 0111. Table 9 shows the content of registers 0 and 1. Table 9: Register Content Reg Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 0 1 1 0 0 0 1 1 1 1 1 1 1 1 0 0 0 1 Rotation Direction By default, when looking at the top of the package, the angle increases when the magnetic field rotates clockwise (CW) (see Figure 15 and Table 10). MA302 Rev. 1.1 2/7/2020 Figure 16: Side-Shaft Field The ratio k depends on the magnet geometry and distance to the sensor. Having a k ratio different than 1 results in the sensor output response not being linear with respect to the mechanical angle. Note that the error curve has the shape of a double sinewave (see Figure 18). E is the amplitude of this error. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 19 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS The X-axis or the Y-axis bias current can be reduced to recover an equal Hall signal for all angles and suppress the error. The parameter ETX and ETY controls in which direction the sensitivity is reduced. The current reduction is set by the parameter bias current trimming BCT(7:0), which is an integer from 0 to 255. In side-shaft configuration (i.e.: the sensor center is located beyond the magnet outer diameter), k is greater than 1. For optimum compensation, the sensitivity of the radial axis should be reduced by setting the BCT parameter as shown in Equation (6):  1 BCT (7 : 0)  2581    k Determining k with the MagAlpha It is possible to deduce the k ratio from the error curve obtained with the default BCT setting (BCT = 0). For this purpose, rotate the magnet over one revolution and record the MagAlpha output. Then plot the error curve (the MagAlpha output minus the real mechanical position vs. the real mechanical position) and extract two parameters: the maximum error E and the position of this maximum with respect to a zero crossing am (see Figure 18). k can be calculated with Equation (7): k (6) Equation (6) is plotted in Figure 17 and Table 11. tan(E  a m ) tan(a m ) 40 200 20  2E Error (deg) m BCT 150 (7) 0 100 -20 50 -40 0 50 100 150 200 250 300 350 rotor angle (deg) 0 1 1.5 2 2.5 3 3.5 4 4.5 5 k Figure 17: Relation between the k Ratio and the Optimum BCT to Recover Linearity Table 11: Example of BCT Settings E (deg) 0 11.5 19.5 25.4 30.0 33.7 36.9 39.5 41.8 MA302 Rev. 1.1 2/7/2020 Magnet Ratio k 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Figure 18: Error Curve in Side-Shaft Configuration with BCT = 0 Some examples are given in Table 11. Alternatively, the k parameter can be obtained from the graph of Figure 19. BCT(7:0) 0 86 129 155 172 184 194 201 207 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 20 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS out of range, defined by the lower and upper magnetic field thresholds, respectively MGLT and MGHT (see Figure 21). 5 4.5 4 k 3.5 3 2.5 2 1.5 1 0 5 10 15 20 25 30 35 40 E (deg) Figure 19: Relation between the Error Measured with BCT = 0 and the Magnet Ratio k Sensor Orientation The dot marked on the package shows whether the radial field is aligned with the sensor coordinate X or Y (see Figure 20). Figure 21: MGH and MGL Signals as a Function of the Field Strength MagHys, the typical hysteresis on the signals MGH and MGL, is 6mT (see Figure 24). The MGLT and MGHT thresholds are coded on three bits and stored in register 6 (see Table 13). Table 13: Register 6 Register 6 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 MGLT MGHT The 3-bit values of MGLT and MGHT correspond to the magnetic field (see Table 14). Table 14: MGLT and MGHT Binary to mT Relation Figure 20: Package Top View with X and Y Axes MGLT or MGHT (8) Determine which axis needs to be reduced (see the qualitative field distribution around a ring in Figure 16). For instance, with the arrangement depicted in Figure 20, the field along the sensor Y direction is tangential and weaker. Therefore, the X-axis should be reduced (ETX = 1 and ETY = 0). Note that if both ETX and ETY are set to 1, the current bias is reduced in both directions the same way (i.e.: without side-shaft correction). 000 001 010 011 100 101 110 111 Table 12: Trimming Direction Parameters ETX 0 1 ETY 0 1 Enable Trimming of the X-Axis Disabled Enabled Enable Trimming of the Y-Axis Disabled Enabled Field threshold in mT From low to high magnetic. field 26 41 56 70 84 98 112 126 (7) From high to low magnetic. field 20 35 50 64 78 92 106 120 NOTES: 7) Valid for VDD = 3.3V. If different, then the field threshold is scaled by the factor VDD/3.3V. 8) MGLT can have a larger value than MGHT. The alarm flags MGL and MGH can be read in register 27 (bit 6 and bit 7), and their logic state is also given at the digital output pins 11 and 16. Magnetic Field Thresholds The magnetic flags (MGL and MGH) indicate that the magnetic field at the sensor position is MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 21 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS To read the MGL and MGH flags via the SPI, send the 16-bit read command to get the register 27 value: command 0 1 0 reg. address 1 1 0 1 1 MGL First Reading value LSB 0 0 0 0 0 0 0 0 MSB The MA302 responds with the register 27 content in the next transmission: MGH MGL Table 15: MGL Multiple Reading Workaround Register 27 [7:0] x x MG1L MG2L x x Known Issue Regarding MGL Pulses with a duration of about 1.3μs to 1.5μs appear randomly in the MGL signal. They appear on both pin and register values (Register 27, bit 6). These pulses appear around angle values of 44, 138, 224, and 318 degrees (sensor output) or in an interval of ±1.5 degree around these values. These pulses have an amplitude of 3.3V (VDD). The minimum interval between two pulses is 100μs. Workarounds 1. Invert the MGH signal to replace MGL. The MGL and MGH magnetic thresholds only differ by a small hysteresis (see Table 16). An inverted MGH signal can be used to replace the MGL output in the application. 2. Read the MGL signal level twice. Using two readings, which must be between 2µs and 100µs apart, allows the user to distinguish erroneous from real transitions. Table 15 shows examples of different cases. 3. Read register 27 with the SPI and compute a corrected MGL value using MG1L and MG2L. The corrected MGL signal = NOT (MG1L OR MG2L). This means that the corrected MGL must be set to 1 only when both MG1L and MG2L are equal to 0. See the C implementation below: Case 1 0 Case 2 Case 3 1 1 MGL Second Reading (e.g. 20μs After the First Reading) Second reading is not needed 1 0 True MGL Value 0 1 0 ABZ Incremental Encoder Output The MA302 ABZ output emulates a 10-bit incremental encoder (such as an optical encoder) providing logic pulses in quadrature (see Figure 22). Compared to signal A, signal B is shifted by a quarter of the pulse period. Over one revolution, signal A pulses N times, where N is programmable from 1 to 256 pulses per revolution. The number of pulses per channel per revolution is programmed by setting the parameter PPT, which consists of eight bits split between registers 0x4 and 0x5 (see Table 5). The factory default value is 256. Table 16 describes how to program PPT(7:0) to set the required resolution. Table 16: PPT Pulses per Turn 1 2 3 4 … 253 254 255 256 PPT(7:0) 00000000 00000001 00000010 00000011 … 11111100 11111101 11111110 11111111 Edges per Turn 4 8 12 16 … 1012 1016 1020 1024 MIN … MAX For example, to set 120 pulses per revolution (480 edges), set PPT to 120 - 1 = 119 (binary: 01110111). Registers 4 and 5 must be set as shown in Table 17. Table 17: Register 4 and Register 5 R4 R5 B7 1 0 B6 1 0 B5 0 0 B4 0 1 B3 0 1 B2 0 1 B1 0 0 B0 0 1 correctedMGL = !(MG1L | MG2L) MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 22 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS Figure 22: Timing of the ABZ Output Signal Z (zero or index) raises only once per turn at the zero-angle position. The position and length of the Z pulse is programmable via bit ILIP(3:0) in register 0x5 (see Figure 23). Figure 23: ILIP Parameter Effect on Index Shape By default, the ILIP parameter is 0000. The index rising edge is aligned with the channel B falling edge and the index length is half the A or B pulse length. ABZ Hysteresis A hysteresis larger than the output noise is introduced on the ABZ output to prevent any spurious transitions (see Figure 24). Figure 24: Hysteresis of the Incremental Output MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 23 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS ABZ Jitter The ABZ state is updated at a frequency of 16MHz, enabling accurate operation up to a very high rpm (above 105 rpm). The jitter characterizes how far a particular ABZ edge can occur at an angular position different from the ideal position (see Figure 25). Figure 26: UVW Output for One Pole Pair Rotor during Rotation Figure 25: ABZ Jitter The measurable jitter is composed of a systematic jitter (always the same deviation at a given angle) and a random jitter. The random jitter reflects the sensor noise, so the edge distribution is the same as the SPI output noise. Like the sensor resolution, it is defined as the 3σ width of this distribution. The random jitter is a function of the rotation speed. At lower speeds, the random jitter is smaller than the sensor noise (see the Typical Characteristic curves on page 7). This is a consequence of the fact that the probability of measuring an edge at a certain distance from the ideal position depends on the number of ABZ updates at this position. The minimum field for ABZ reading is 30mT. Block Commutation – UVW The UVW output emulates the three Hall switches usually used for the block commutation of a three-phase electric motor. The three logic signals have a duty cycle of 50% and are shifted by 60° relative to each other (see Figure 26). MA302 Rev. 1.1 2/7/2020 If the number of pole pairs of the motor exceeds the number of pole pairs of the target magnet, the MA302 is able to generate more than one UVW cycle per revolution. It does this by dividing the digital angle into the required number of commutation steps per 360° revolution. The parameter NPP(2:0) in register 0x7 sets the number of pole pairs emulated, and the corresponding commutation step angle for the UVW signals. Table 18 describes the pole pair configuration options. Table 18: Number of UVW Pair Poles NPP (2:0) 000 001 010 011 100 101 110 111 Pole Pairs 1 2 3 4 5 6 7 8 States per Revolution 6 12 18 24 30 36 42 48 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. State Width (deg) 60 30 20 15 12 10 8.6 7.5 24 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS An example of the 30° UVW commutation signal spacing for a four-pole (two-pole pair) motor is shown in Figure 27. UVW Hysteresis A hysteresis larger than the output noise is introduced on the UVW output to avoid any spurious transitions (see Figure 28). Figure 27: UVW Commutation Signals for a FourPole (Two-Pole Pair) Motor Figure 28: Hysteresis of the UVW Signal MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 25 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS TYPICAL APPLICATION CIRCUITS Figure 29: Typical Configurations Using SPI Interface and MGH/MGL Signals Figure 30: Typical Motor Configuration Using UVW Commutation Signals MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 26 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS PACKAGE INFORMATION QFN-16 (3mmx3mm) MA302 Rev. 1.1 2/7/2020 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2020 MPS. All Rights Reserved. 27 MA302 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS APPENDIX A: DEFINITIONS Effective Resolution (3σ noise level) The smallest angle increment distinguishable from the noise. The resolution is measured by computing 3 times σ (the standard deviation in degrees) taken over 1,000 data points at a constant position. The resolution in bits is obtained with log2(360/6σ). Refresh Rate Rate at which new data points are stored in the output buffer. ABZ Update Rate Rate at which a new ABZ sate is computed. The inverse of this rate is the minimum time between 2 ABZ edges. Latency The time elapsed between the instant when the data is ready to be read and the instant at which the shaft passes that position. The lag in degrees is , where 𝑣 is the angular velocity in deg/s. Power-Up Time Time until the sensor delivers valid data starting at power-up. Integral Non-Linearity (INL) Maximum deviation between the average sensor output (at a fixed position) and the true mechanical angle. 400 sensor out (deg) 350 300 lag 250 ideal sensor output 200 150 INL 100 0 sensor out best straight fit resolution ( ± 3 ) 50 0 100 200 300 400 500 600 700 rotor position (deg) It can be obtained from the error curve , where is the average over 1,000 sensor outputs, and is the mechanical angle indicated by a high precision encoder (