Datasheet KMA210 (NXP) - 4

NXP Semiconductors KMA210 Programmable angle sensor 5. Functional description
The KMA210 amplifies two orthogonal differential signals from MR sensor bridges and converts them into the digital domain. The angle is calculated using the COordinate Rotation DIgital Computer (CORDIC) algorithm. After a digital-to-analog conversion the analog signal is provided to the output as a linear representation of the angular value. Zero angle, clamping voltages and angular range are programmable. In addition, two 16-bit registers are available for customer purposes, such as sample identification. The KMA210 comprises a Cyclic Redundancy Check (CRC) and an Error Detection and Correction (EDC), as well as magnet-loss and broken bond wire detection to ensure a fail-safe operation. A power-loss detection circuit pulls the analog output to the remaining connection, if either the supply voltage or the ground line of the mixed signal IC is interrupted. After multiplexing the two MR Wheatstone bridge signals and their successive amplification, the signal is converted into the digital domain by an Analog-to-Digital Converter (ADC). Further processing is done within an on-chip state machine. This includes offset cancellation, calculation of the mechanical angle using the CORDIC algorithm, as well as zero angle and angular range adjustment. The internal Digital-to-Analog Converter (DAC) and the analog output stage are used for conversion of the angle information into an analog output voltage, which is ratiometric to the supply voltage. The configuration parameters are stored in a user-programmable non-volatile memory. The OWI (accessible using pin OUT/DATA) is used for accessing the memory. In order to protect the memory content a lock bit can be set. After locking the non-volatile memory, its content cannot be changed anymore.
5.1 Angular measurement directions
The differential signals of the MR sensor bridges depend only on the direction of the external magnetic field strength Hext, which is applied parallel to the plane of the sensor. In order to obtain a correct output signal, the minimum saturation field strength has to be exceeded. KMA210 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 2 — 7 December 2011 4 of 37
Document Outline 1. Product profile 1.1 General description 1.2 Features and benefits 2. Pinning information 3. Ordering information 4. Functional diagram 5. Functional description 5.1 Angular measurement directions 6. Analog output 7. Diagnostic features 7.1 CRC and EDC supervision 7.2 Magnet-loss detection 7.3 Power-loss detection 7.4 Broken bond wire detection 7.5 Low supply voltage detection and overvoltage protection 8. Limiting values 9. Recommended operating conditions 10. Thermal characteristics 11. Characteristics 12. Definition of errors 12.1 General 12.2 Hysteresis error 12.3 Linearity error 12.4 Microlinearity error 12.5 Temperature drift error 12.6 Angular error 13. Programming 13.1 General description 13.2 Timing characteristics 13.3 Sending and receiving data 13.3.1 Write access 13.3.2 Read access 13.3.3 Entering the command mode 13.4 Cyclic redundancy check 13.4.1 Software example in C 13.5 Registers 13.5.1 Command registers 13.5.2 Non-volatile memory registers 14. Electromagnetic compatibility 14.1 Emission (CISPR 25) 14.1.1 Conducted radio disturbance 14.1.2 Radiated radio disturbance 14.2 Radiated disturbances (ISO 11452-1 third edition (2005-02), ISO 11452-2, ISO 11452-4 and ISO 11452-5) 14.2.1 Absorber lined shielded enclosure 14.2.2 Bulk-current injection 14.2.3 Strip line 14.2.4 Immunity against mobile phones 14.3 Electrical transient transmission by capacitive coupling [ISO 7637-3, second edition (2007-07)] 15. ElectroStatic Discharge (ESD) 15.1 Human body model (AEC-Q100-002) 15.2 Human metal model (ANSI/ESD SP5.6-2009) 15.3 Machine model (AEC-Q100-003) 15.4 Charged-device model (AEC-Q100-011) 16. Application information 17. Test information 17.1 Quality information 18. Marking 19. Terminals 20. Package outline 21. Handling information 22. Solderability information 23. Revision history 24. Legal information 24.1 Data sheet status 24.2 Definitions 24.3 Disclaimers 24.4 Trademarks 25. Contact information 26. Contents