AS5145H/AS5145A/AS5145B 12-Bit Programmable Magnetic Rotary Encoder Three incremental outputs 1 General Description Quadrature A/B/I (10 or 12 bit) and Index output signal (pre- The AS5145 is a contact less magnetic rotary encoder for accurate programmed versions available AS5145A for 10-bit and angular measurement over a full turn of 360 degrees. AS5145B for 12-bit) It is a system-on-chip, combining integrated Hall elements, analog User programmable zero position front end and digital signal processing in a single device. Failure detection mode for magnet placement, monitoring, and To measure the angle, only a simple two-pole magnet, rotating over loss of power supply the center of the chip, is required. The magnet can be placed above Red-Yellow-Green indicators display placement of magnet in Z- or below the IC. axis The absolute angle measurement provides instant indication of the Serial read-out of multiple interconnected AS5145 devices magnets angular position with a resolution of 0.0879 = 4096 using Daisy Chain mode positions per revolution. This digital data is available as a serial bit stream and as a PWM signal. Tolerant to magnet misalignment and gap variations An internal voltage regulator allows the AS5145 to operate at either Wide temperature range: - 40C to +150C 3.3V or 5V supplies. Fully automotive qualified to AEC-Q100, grade 0 Small Pb-free package: SSOP 16 (5.3mm x 6.2mm) 2 Key Features 3 Applications Contact less high resolution rotational position encoding over a full turn of 360 degrees The device is ideal for industrial applications like contactless rotary position sensing and robotics automotive applications like steering Two digital 12-bit absolute outputs: wheel position sensing, transmission gearbox encoder, head light - Serial interface position control, torque sensing, valve position sensing and - Pulse width modulated (PWM) output replacement of high end potentiometers. Figure 1. AS5145 Automotive Rotary Encoder IC VDD3V3 MagINCn MagDECn VDD5V LDO 3.3V PWM PWM Interface Sin Ang DO DSP Absolute Cos Mag Hall Array Interface CSn & (SSI) Frontend CLK Amplifier OTP PDIO Register DTEST1 A Incremental Mux DTEST2 B AS5145 Interface Mode Index www.ams.com/AS5145 Revision 1.17 1 - 36AS5145 Datasheet - Contents Contents 1 General Description .................................................................................................................................................................. 1 2 Key Features............................................................................................................................................................................. 1 3 Applications............................................................................................................................................................................... 1 4 Pin Assignments ....................................................................................................................................................................... 4 4.1 Pin Descriptions.................................................................................................................................................................................... 4 5 Absolute Maximum Ratings ...................................................................................................................................................... 6 6 Electrical Characteristics........................................................................................................................................................... 7 6.1 Magnetic Input Specification................................................................................................................................................................. 8 6.2 System Specifications .......................................................................................................................................................................... 9 7 Timing Characteristics ............................................................................................................................................................ 11 8 Detailed Description................................................................................................................................................................ 12 8.1 Mode Index Pin.................................................................................................................................................................................. 12 8.1.1 Synchronous Serial Interface (SSI) ........................................................................................................................................... 13 8.1.2 Incremental Mode ...................................................................................................................................................................... 14 8.1.3 Sync Mode................................................................................................................................................................................. 16 8.1.4 Sin/Cosine Mode ....................................................................................................................................................................... 16 8.1.5 Daisy Chain Mode ..................................................................................................................................................................... 16 8.2 Pulse Width Modulation (PWM) Output.............................................................................................................................................. 17 8.2.1 Changing the PWM Frequency.................................................................................................................................................. 18 8.3 Analog Output..................................................................................................................................................................................... 18 9 Application Information ........................................................................................................................................................... 19 9.1 Programming the AS5145 .................................................................................................................................................................. 19 9.1.1 Zero Position Programming ....................................................................................................................................................... 19 9.1.2 OTP Memory Assignment.......................................................................................................................................................... 20 9.1.3 User Selectable Settings ........................................................................................................................................................... 20 9.1.4 OTP Default Setting................................................................................................................................................................... 21 9.1.5 Redundancy............................................................................................................................................................................... 21 9.1.6 Redundant Programming Option ............................................................................................................................................... 22 9.1.7 OTP Register Entry and Exit Condition ..................................................................................................................................... 22 9.2 Alignment Mode.................................................................................................................................................................................. 23 9.3 3.3V / 5V Operation............................................................................................................................................................................ 24 9.4 Selecting Proper Magnet.................................................................................................................................................................... 24 9.4.1 Physical Placement of the Magnet ............................................................................................................................................ 25 9.4.2 Magnet Placement..................................................................................................................................................................... 26 9.5 Failure Diagnostics............................................................................................................................................................................. 26 9.5.1 Magnetic Field Strength Diagnosis............................................................................................................................................ 26 9.5.2 Power Supply Failure Detection ................................................................................................................................................ 26 9.6 Angular Output Tolerances................................................................................................................................................................. 26 9.6.1 Accuracy.................................................................................................................................................................................... 26 9.6.2 Transition Noise......................................................................................................................................................................... 28 9.6.3 High Speed Operation ............................................................................................................................................................... 28 9.6.4 Propagation Delays ................................................................................................................................................................... 28 9.6.5 Internal Timing Tolerance .......................................................................................................................................................... 29 9.6.6 Temperature .............................................................................................................................................................................. 29 9.6.7 Accuracy over Temperature ...................................................................................................................................................... 29 www.ams.com/AS5145 Revision 1.17 2 - 36