At Sensors Expo, Wayne Seto, Senior Director of Product Marketing from Crocus Technology, discusses the company’s tunnel magnetoresistance (TMR) magnetic sensing technology. For sensing, TMR is used in number of different applications. Wayne demonstrated several digital latches with omnipolar (CT832DM), bipolar (CT852AN), unipolar (CT832EK, CT832BV, CT832SK and CT811DK) and analog (CT834DR) magnetics.

For omnipolar sensing for digital latches, the CT832SK provides high sensitivity, the CT832BV medium sensitivity and the CT832EK low sensitivity. The CT811DK enables a unipolar, single direction latch. In contrast, the CT852AN bipolar latch turns on with one magnetic direction and off with the opposite direction. With the CT832DM omnipolar sensor, the latch turns on or off with either magnet.

The CT834DR analog sensor senses the magnetic field for contactless current measurements and the demo showed the magnet’s proximity in either direction in a series of steps.

Unlike Hall effect sensors, Crocus’ TMR uses patented Magnetic Logic Unit (MLU) technology. MLU enables the TMR sensor products to have high magnetic sensitivity with minimal variation over a wide temperature range and ultra-low power consumption. The basis of MLU technology is a thin film magnetic tunnel junction (MTJ) device. The simplest MTJ consists of two magnetic layers on both sides of a thin insulating layer: one layer has a fixed magnetic moment and the other can change freely in the presence of a magnetic field.

In addition to the sensors shown in the demo, Crocus Technology also offers rotation/speed sensors with response up to 45,000 rpm and angular sensors with better than 2% accuracy.

For more information on Crocus Technology magnetic sensors, click here.