ADA4571
Recommended for New Designs
The ADA4571 is an anisotropic magnetoresistive (AMR) sensor
with integrated signal conditioning amplifiers and ADC drivers.
The ADA4571 produces two analog...
Datasheet
ADA4571 on Analog.com
ADA4571-2
Recommended for New Designs
The ADA4571-2 is a 2-channel anisotropic magneto resistive (AMR) sensor with integrated signal conditioning amplifiers
and ADC drivers. The device produces...
Datasheet
ADA4571-2 on Analog.com
ADA4570
Recommended for New Designs
The ADA4570 is an anisotropic magnetoresistive (AMR) sensor with integrated signal conditioning amplifiers and analog-to-digital converter (ADC) drivers...
Datasheet
ADA4570 on Analog.com
AD7380
Production
The AD7380/AD7381 are a 16-bit and 14-bit pin-compatible family of dual simultaneous sampling, high speed, low power, successive approximation register...
Datasheet
AD7380 on Analog.com
LT3023
Recommended for New Designs
The LT3023 is a dual, micropower, low noise, low dropout regulator. With an external 0.01µF bypass capacitor, output noise drops to 20µVRMS over a 10Hz...
Datasheet
LT3023 on Analog.com
ADP320
Recommended for New Designs
The ADP320 200 mA triple output LDO combines high PSRR, low
noise, low quiescent current, and low dropout voltage in a voltage
regulator ideally suited...
Datasheet
ADP320 on Analog.com
LT3029
Recommended for New Designs
The LT3029 is a dual, micropower, low noise, low dropout linear regulator. The device operates either with a common input supply or independent input supplies...
Datasheet
LT3029 on Analog.com
ADM3066E
Production
The ADM3061E/ADM3062E/ADM3063E/ADM3064E/ADM3065E/ADM3066E/ADM3067E/ADM3068E are 3.0 V to
5.5 V, IEC electrostatic discharge (ESD) protected RS-485
transceivers...
Datasheet
ADM3066E on Analog.com
ADM3065E
Production
The ADM3061E/ADM3062E/ADM3063E/ADM3064E/ADM3065E/ADM3066E/ADM3067E/ADM3068E are 3.0 V to
5.5 V, IEC electrostatic discharge (ESD) protected RS-485
transceivers...
Datasheet
ADM3065E on Analog.com
MAX32672
Recommended for New Designs
In the DARWIN family, the MAX32672 is an ultra-low-power, cost-effective, highly integrated, and highly reliable 32-bit microcontroller enabling designs...
Datasheet
MAX32672 on Analog.com
ADXL371
Recommended for New Designs
The ADXL371 is an ultra low power, 3-axis, ±200 g microelectromechanical system (MEMS) accelerometer that consumes 28 µA at a 2560 Hz output data rate...
Datasheet
ADXL371 on Analog.com
ADT7320
Recommended for New Designs
The ADT7320 is a high accuracy digital temperature sensor that offers breakthrough performance over a wide industrial temperature
range, housed in a 4...
Datasheet
ADT7320 on Analog.com
by Richard Anslow and Michael Jackson
The last blog in this series reviewed some emerging trends in motor encoder applications. This blog looks at the benefits of using magnetic encoders based on anisotropic magnetoresistive (AMR) sensors and shows how to use components from ADI to realize a complete asset monitoring encoder solution.
Sensing
Among magnetic-based position sensors, AMR sensors offer the best combination of robustness and accuracy. This sensor type is typically positioned opposite a Dipole magnet attached to the motor shaft as shown in Figure 1.
Figure 1 Using an AMR sensor to detect motor position
AMR sensors are sensitive to magnetic field direction changes, unlike Hall effect sensors which are sensitive to field intensity. This means AMR sensors are very tolerant to airgap and mechanical tolerance variation in the system. Furthermore, since there is no upper limit on the operating magnetic field, AMR sensors are extremely robust to stray magnetic fields. The ADA4571 is an AMR sensor with low latency integrated signal conditioning and has a single-ended analog output. The ADA4571 single chip provides guaranteed angular accuracy (only 0.10 typical angular error) and can operate at speeds up to 50K rpm. The ADA4571-2 is a dual version that provides full redundancy without compromising performance in applications that are safety-critical. The ADA4570 is a derivative of the ADA4571 with the same performance but with a differential output for use in harsher environments. The high angular accuracy and repeatability provided by the ADA457x family improve closed-loop control, reducing motor torque ripple and noise. This single-chip architecture improves reliability, reduces size, and weight, and is easier to integrate compared to competing technologies.
Signal Conditioning and Power
The AD7380 is a dual simultaneous sampling, 16-bit SAR ADC offering many system-level benefits, including a space-saving 3 mm × 3mm package, an important feature for space-constrained encoder PCB boards. Its 4 MSPS throughput rate ensures that detailed sine and cosine cycles are captured and encoder positions are up to date. The high throughput rate enables oversampling on-chip, which reduces the time penalty of digital ASICs or microcontrollers feeding the precise encoder position to the motor. Another benefit of on-chip oversampling is that it allows for an additional 2 bits of resolution, using the AD7380’s resolution boost feature. The VCC and VDRIVE of the ADC and the supply rails of the amplifier driver can be powered by an LDO regulator, such as the LT3023. Multiple output low-noise LDOs like the ADP320, LT3023, and LT3029 can be used to power all components in the signal chain.
Transceiver
The ADM3066E RS-485 transceiver exhibits ultra-low transmitter and receiver skew performance, which makes it ideal for transmission of a precision clock, which often features in motor encoding standards, such as EnDat 2.2.4 The ADM3065E demonstrates less than 5% deterministic jitter across typical cable lengths encountered in motor control applications. The wide supply range of the ADM3065E means that it is suitable for applications that require either a 3.3 V or 5 V transceiver power supply.
Microcontroller
For lower-resolution applications (12 bits or less), an alternative approach is to use a microcontroller with integrated ADC. The tiny MAX32672 ultra-low power Arm® Cortex® -M4F microcontroller includes a 12-bit 1 MSPS ADC with enhanced security, peripherals, and power management interfaces.
Asset Health Monitoring Encoder Solution
The complete signal chain for asset health monitoring AMR sensor-based application is shown in Figure 2. This solution features the ADXL371, an ultralow power, 3-axis, digital output, ±200 g microelectromechanical system (MEMS) accelerometer designed for machine monitoring. The cost-effective IC is available in a small 3 mm × 3 mm package and operates at temperatures up to +105°C. In instant-on mode, the ADXL371 consumes only 1.7 μA when continuously monitoring the environment for vibrations. If it detects an impact event that exceeds the internally set threshold, the device switches to normal operating mode quickly enough to record the event. Another notable component is the ADT7320, a high-accuracy digital temperature sensor, which does not require user calibration or correction and has excellent long-term stability and reliability. This IC is rated for operation over an extended range of −40°C to +150°C and is available in a small 4 mm × 4mm LFCSP package.
Figure 2 Signal chain for an AMR sensor-based asset monitoring solution
A list of ADI-recommended components for this signal chain is shown in the table below.
The next blog in this series will look at signal chains for encoders based on Hall-effect sensors as well as optical and resolver (coupled) encoder solutions.