iC-TW39: 24-Bit TMR Angle Sensor
iC-Haus presents its new, universal TMR angle sensor for on-axis applications, especially for motor feedback systems. iC-TW39 is suitable for high-resolution incremental and absolute measuring systems and also supports multiturn applications.
Due to its magnetic tunnel resistance, the innovative 24-bit TMR sensor can track the field vector of a rotating magnet at the shaft end. The resistance changes proportional to the magnetization direction, so 360 degrees are sensed precisely.
This TMR angle sensor offers several advantages over conventional Hall sensors: Due to its high sensitivity, higher operating distances are possible. This allows a higher axial play of the motor axis and larger installation tolerances. The quantum tunneling that comes with the iC-TW39 causes high output voltages for the TMR output signal, which reaches several hundreds of millivolts (typ. 500 mV with a magnetic flux density of 50 mT). Thus, no complex signal amplification is necessary, resulting in an optimal signal-to-noise ratio. Other significant advantages are its low temperature coefficient of output voltage, its low offset drift and its extremely high angular accuracy at concurrent low power consumption.
By using a high-resolution on-chip interpolator with digital filtering and automatic error correction, the iC-TW39 ensures minimal angular error of only ±0.15° (INL) and excellent position jitter (e.g. ±2% at 2,500 cpr) even with unprecedented low position noise at standstill. Also long latency times that occur with conventional Hall sensors are negligible with TMR technology: with only 1.5 µs, the sensor responds with virtually no delay.
To achieve high angular accuracies with relaxed installation tolerances, this smart system-on-chip is capable of automatically calibrating the TMR sensor signals to compensate for multiple signal errors. In addition to calibration at the push of a button, constant auto-correction is available. This makes it easy to compensate for offset drift over temperature and reliably maintain high measuring accuracy in continuous applications. With the chip, uncorrected and residual errors and random deviations can also be easily monitored digitally and then be reported to the control – a function that is in great demand for predictive maintenance and drive monitoring.
Fast data processing updates the absolute angular position every 20 ns for immediate output via BiSS or SSI. Additionally, incremental ABZ signals with resolutions from 1 to 65,536 cycles per revolution or UVW commutation signals for 1- to 32-pole pair motors are available. The iC-TW39 can easily be configured via the bidirectional BiSS interface or SPI.
Typical applications for iC-Haus’ iC-TW39 include high-resolution angle measuring, brushless motor commutation, servo motor control and incremental as well as absolute encoders.
The sensor is designed for operating temperatures from -40 to 125°C. It requires a supply voltage of typ. 3.3 V with a current consumption of typ. 30 mA. The iC-TW39 can be used for sensing diametric magnets. iC-Haus offers reference magnet targets of Ø 9 mm or Ø 14 mm (MAG-4000 and 4001, resp.).