MT6835 Rev.1 - MagnTek

1 MT6835 . 21-Bit High Accuracy Magnetic Encoder IC. Features and Benefits Based on advanced AMR Technology with 0~360 Full Range Angle Sensing 21-bit Core Resolution with Maximum Rotation Speed Up to 120,000 RPM. Output Propagation Delay <10 us User Auto-Calibration and Distortion Compensation with Target INL< . -40~125 Operating Temperature Range Independent Output Interface: ABZ, UVW General Description PWM and SPI. MagnTek 's rotary position sensor MT6835 . Incremental ABZ Resolution 1~16,384 Pulses is an IC based on advanced AMR. per Revolution User Programmable technology. A rotating magnetic field in the x-y sensor plane delivers two sinusoidal UVW Output Resolution 1~16 Pole-Pairs per output signals which indicating the angle Revolution User Programmable ( ) between the sensor and the magnetic ~ Programmable EEPROM field direction. The sensor is only sensitive to the magnetic field direction in x-y plane as the sensing element output is specially designed to be independent from the magnet field strength.

2 This allows the device to be less sensitive to magnet variations, stray magnetic fields, air gap changes and off-axis misalignment. The incremental ABZ output mode is available in this sensor series, making the Applications chip suitable to replace various optical encoders. The maximum resolution is Absolute Angle Position Sensor 16,384 pulses or 65,536 steps per revolution BLDC Motor Control A 4-Wire SPI interface allows a host Servo Motor Control microcontroller to read out the 21-bit absolute angle position data from MT6835 . Stepping Motor Control The absolute angle position is also provided Optical Encoder Replacement as a 12-bit PWM output. | Magnetic Tech Makes Magic Change 1 MT6835 . 21-Bit High Accuracy Magnetic Encoder IC. Table of Contents Features and Benefits .. 1. Applications ..1. General Description .. 1. 1 Pin Configuration ..3. 2 Function Diagram . 4. 3 Absolute Maximum Ratings.

3 5. 4 Operating Conditions ..5. 5 Electrical Characteristics ..6. 6 Magnetic Input ..8. 7 Output Mode ..9. I/O Pin Configuration .. 9. Reference Circuit ..10. Quadrature A,B and Zero-Position Output Signal (ABZ Mode) ..11. UVW Output Mode ..16. Pulse Width Modulation (PWM) Output Mode.. 17. SPI Interface ..18. SPI Reference Circuit ..18. SPI Timing Diagram ..19. SPI Protocol.. 20. SPI Read One Byte Register ..21. SPI Write One Byte Register .. 21. SPI Program EEPROM .. 22. SPI Auto Setting Zero Position .. 23. SPI Single Byte Read Angle .. 23. SPI Burst Read Angle .. 25. 8 Change & Program Zero Position to EEPROM ..26. 9 Calibration .. 27. Factory Calibration .. 27. User Auto-Calibration ..28. User NLC Calibration ..29. 10 Register Map ..30. 11 Magnet ..37. 12 Mechanical Angle Direction ..38. 13 Package Information ..39. 14 Copy Rights and Disclaimer ..40. 15 Revision History ..41. | Magnetic Tech Makes Magic Change 2 MT6835 .

4 21-Bit High Accuracy Magnetic Encoder IC. 1. Pin Configuration 16 15 14 13 12 11 10 9. Sensing Center at Geometry Center 1 2 3 4 5 6 7 8. Figure 1: Pin Configuration of MT6835 (TSSOP-16) Package I/O Pin List I/O Name # I/O Type Description U 1 Digital Output Commutation Signal U or A. V 2 Digital Output Commutation Signal V or B. W 3 Digital Output Commutation Signal W or -Z. CAL_EN 4 Digital Input Auto-Calibration Enable Pin MISO 5 Digital Output SPI Data, Slave Output Master Input MOSI 6 Digital Input SPI Data, Master Output Slave Input SCK 7 Digital Input SPI Clock CSN 8 Digital Input SPI Select VDD 9 Power Supply ~ Power Supply OUT 10 Digital Output PWM Output TEST 11 Analog Input Factory Test Pin VSS 12 Power Supply Ground TEST_EN 13 Digital Input Factory Test Enable Z 14 Digital Output Incremental Signal Z. B 15 Digital Output Incremental Signal B. A 16 Digital Output Incremental Signal A. Family Members Part Number Description MT6835GT-STD TSSOP-16 Package, Tube (60 Pcs/Tube) or Reel (3000 Pcs/Reel).

5 *TSSOP-16 Reflow Sensitivity Classification: MSL-3. | Magnetic Tech Makes Magic Change 3 MT6835 . 21-Bit High Accuracy Magnetic Encoder IC. 2. Functional Diagram The MT6835 is manufactured in a CMOS standard process and uses advanced magnet sensing technology to sense the magnetic field distribution across the surface of the chip. The integrated magnetic sensing element array is placed around the center of the device and delivers a voltage representation of the magnetic field at the surface of the IC. VDD. LDO EEPROM DSP. PWM. ( Angle, OUT. Angle velocity ). Calculation Magnetic Sensing G ADC. Element A. ABZ. B. Calibration Z. G ADC. M U. UVW/. -A-B-Z. U V. X W. I/V Interpolator MOSI. OSC MISO. REF SPI. SCK. VSS CAL_EN TEST TEST_EN CSN. Figure 2: Block Diagram Figure 2 shows a simplified block diagram of the chip, consisting of the magnetic sensing element modeled by two interleaved Wheatstone bridges to generate cosine and sine signals, gain stages, analog-to-digital converters (ADC) for signal conditioning, and a digital signal processing (DSP) unit for encoding .

6 Other supporting blocks such as LDO, etc. are also included. | Magnetic Tech Makes Magic Change 4 MT6835 . 21-Bit High Accuracy Magnetic Encoder IC. 3. Absolute Maximum Ratings (Non-Operating). Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only. Functional operation of the device at these or any other conditions beyond those indicated under Operating Conditions is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Parameter Min. Max. Unit Notes DC Voltage at Pin VDD V. Terminal Voltage at Input ABZ, UVW, MISO, MOSI, SCK, CSN, VDD V. and Output Pins TEST_EN, OUT, CAL_EN, Test Output Current at Output Pins -20 20 mA ABZ, UVW, OUT, MISO. Storage Temperature -40 150 . ISCR (Latch-up Input Current) - 100 mA AEC-Q100-004. VHBM (ESD Voltage) - KV AEC-Q100-002. VCDM (ESD Voltage) - KV AEC-Q100-011.

7 4. Operating Conditions Parameter Min. Max. Unit DC Voltage at Pin VDD V. Magnetic Flux Density Range 30 200 mT. Rotation Speed - 120,000 RPM. Operating Temperature -40 125 . | Magnetic Tech Makes Magic Change 5 MT6835 . 21-Bit High Accuracy Magnetic Encoder IC. 5. Electrical Characteristics Operation conditions: Ta=-40 to 125 , VDD= ~ unless otherwise noted. Symbol Parameter Conditions/Notes Min. Typ. Max. Unit VDD Supply Voltage - ~ V. Idd Supply Current - 15 22 28 mA. LSB Resolution (ABZ Mode) N Steps per Cycle - 360 /N - . Integral Non-Linearity with Note (1) - . Factory Calibration INL. Integral Non-Linearity with Note (2) . User Auto-Calibration Differential Non-Linearity (ABZ. DNL @2500 PPR - - . Mode), Figure 3. TN Transition Noise (ABZ Mode) 25 with 'BW'=5 - - rms Hyst Hysteresis Programmable - - . TPwrUp Power-Up Time VDD Ramp<100us - 64 - ms TDelay Propagation Delay Constant Speed - 10 - us TST Step Response Time Regsiter BW'=5 - 100 - us Note (1): The typical error value can be achieved at room temperature and with no off-axis misalignment error.

8 The maximum error value can be achieved over operation temperature range, at maximum air gap and with worst-case off-axis misalignment error. Note (2): Please follow chapter 9 for the detail of User Auto-Calibration'. PWM Output Characteristics Operation conditions: Ta=-40 to 125 , VDD= ~ unless otherwise noted. Symbol Parameter Conditions/Notes Min. Typ. Max. Unit FPWM PWM Frequency Programmable -8% 497/994 +8% Hz TRise Rising Time CL=1nF - - 1 us TFall Falling Time CL=1nF - - 1 us | Magnetic Tech Makes Magic Change 6 MT6835 . 21-Bit High Accuracy Magnetic Encoder IC. EEPROM Characteristics Operation conditions: Ta=-40 to 125 , VDD= ~ unless otherwise noted. Symbol Parameter Min. Typ. Max. Unit VDD Supply Voltage @Erase/Program EEPROM - V. Endurance Erase/Program Cycles 1,000 - - Cycles Retention Data Retention @150 10 - -- Years Digital I/O Characteristics Operation conditions: Ta=-40 to 125 , VDD= ~ unless otherwise noted.

9 Symbol Parameter Conditions/Notes Min. Typ. Max. Unit Digital I/O Input Voltage VIH High Level Voltage - *VDD - - V. (CSN, MISO, CLK, CAL_EN). Digital I/O Input Voltage VIL Low Level Voltage - - - *VDD V. (CSN, MISO, CLK, CAL_EN). Digital I/O Output High VOH Level Voltage Push-Pull (@Iout=-2mA) - - V. (ABZ, UVW, MISO, OUT). Digital I/O Output Low VOL Level Voltage Push-Pull (@Iout=2mA) - - V. (ABZ, UVW, MISO, OUT). Figure 3: Drawing Illustration INL, DNL and TN (for 10-bit case). | Magnetic Tech Makes Magic Change 7 MT6835 . 21-Bit High Accuracy Magnetic Encoder IC. 6. Magnetic Input Specifications Operation conditions: Ta=-40 to 125 , VDD= ~ unless otherwise noted, two-pole cylindrical diametrically magnetized source. Symbol Parameter Conditions/Notes Min. Typ. Max. Unit Recommended Magnet: Dmag Diameter of Magnet 10mm x for - 10 - mm Cylindrical Magnets Tmag Thickness of Magnet - - - mm Magnetic Input Field Bpk Measure at the IC Surface 30 - 1,000 mT.

10 Amplitude Magnetic to IC Surface AG Air Gap - mm Distance RS Rotation Speed Turn Rounds per Minute - - 120,000 RPM. Misalignment Error Between Sensor Sensing DISP Off Axis Misalignment - - mm Center and Magnet Axis (See Figure 4). NdFeB (Neodymium Iron TCmag1 Recommended Magnet - - Boron). Material and Temperature %/ . TCmag2 Drift Coefficient SmCo (Samarium Cobalt) - - Off-axis Misalignment N S. Air Gap Figure 4: Magnet Arrangement | Magnetic Tech Makes Magic Change 8 MT6835 . 21-Bit High Accuracy Magnetic Encoder IC. 7. Output Mode The MT6835 provides ABZ, UVW and PWM signals at output pins, and the 21-bit absolute angle position data could be transferred by the standard 4-Wire SPI interface. I/O Pin Configuration For TSSOP-16 package, ABZ (Single-end or differential), UVW, PWM and SPI Interface are configured as below table. I/O Pin Configuration Pin# UVW+SPI+PWM+ABZ -A-B-Z+SPI+PWM+ABZ. 1 U -A.