Stray field robust linear TMR sensor enables high-precision length measurements

Infineon Technologies AG has combined its expertise in magnetic position sensors with its established linearised TMR technology to launch the XENSIV TLI5590-A6W magnetic position sensor. The sensor comes in a wafer-level package, ideal for linear and angular incremental position detection. The device is qualified for industrial and consumer applications according to the JEDEC standard JESD47K and can replace optical encoders and resolvers. It is ideal for positioning lenses for zoom and focus adjustment in cameras.

The sensor is a low-field sensor with the company's TMR technology developed for high-volume sensor systems. As a result, the sensor delivers ultra-high sensitivity, low jitter, and low power consumption. Compared to linear Hall sensors, TMR sensors provide better linearity, lower noise, and lower hysteresis. The high signal-to-noise ratio and the lower power allow cost-effective magnetic designs with lower battery consumption.

As a result, the new sensor allows accurate detection with rapidly changing directions. The sensor comprises two TMR Wheatstone bridges, where the TMR resistance depends on the direction and strength of the external magnetic field. In combination with a multipole magnet, each bridge supplies a differential output signal, i.e., sine and cosine signals. These can be further processed for relative position measurement.

The sensor is housed in an extremely small six-ball wafer-level package SG-WFWLB-6-3. Due to the higher integration density, the sensor size has been decreased, which supports miniaturisation and position detection in microsystems. The TLI5590-A6W allows fine measurement with a significantly high accuracy of better than 10µm, which is accomplished by utilising a suitable linear or rotary magnetic encoder. With an extended operating temperature range of up to +125C, the sensor can be used flexibly in diverse industrial and consumer applications. Also, its high-temperature stability makes it the perfect option for harsh environments.