New omnipolar and bipolar TMR switches from Littelfuse

Littelfuse, an industrial technology manufacturing company, has launched two next-generation Tunnelling Magnetoresistance (TMR) magnetic switches: the LF21112TMR omnipolar switch and the LF11215TMR bipolar switch

These devices can provide greater magnetic sensitivity, thermal stability, and ultra-low power consumption, enabling energy-efficient sensing solutions for smart meters, wearables, industrial automation, consumer electronics, and home security systems.

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The LF21112TMR

The LF21112TMR is Littelfuse’s first omnipolar TMR switch and can detect both North and South magnetic poles, enabling greater flexibility in magnet placement and simplifying design. The switch has a typical current draw of 200nA, making it suitable for ultra-low-power applications.

Omnipolar switches can activate a response when exposed to either magnetic pole, making them suited for space-constrained designs and applications where magnet alignment is difficult to control.

The LF11215TMR

The LF11215TMR is a bipolar digital TMR switch that provides high-speed, precision detection with ultra-low 1.5 µA current consumption and a magnetic sensitivity of 17 Gauss.

Bipolar switches are triggered by specific magnetic polarity, typically North, and reset with the opposite polarity. This directional sensitivity is ideal for applications requiring rotational or directional sensing.

Features and applications

Both devices are housed in SOT23-3 packages and feature:

TMR technology
Push-pull CMOS output
Immunity to external magnetic interference
Wide operating voltage of 1.8V to 5.0V
Schmitt trigger inputs

These switches are ideal for:

Smart utility meters
Lid and cover detection in appliances and power tools
Battery-powered wearables and IoT sensors
Rotary and linear position sensing in light industrial and robotic equipment
Tamper detection in home and building automation

Julius Venckus, global product manager at Littelfuse, said, “With the LF21112TMR and LF11215TMR, we’re expanding the Littelfuse TMR sensor portfolio with solutions that address critical design challenges in today’s compact, battery-powered, and always-on devices. Both switches integrate Tunnelling Magnetoresistance technology with ultra-low power CMOS design, delivering exceptional magnetic sensitivity and thermal stability at industry-leading current levels, just 200nA for omnipolar sensing and 1.5 µA for bipolar.”

Venckus added, “These innovations empower engineers to extend battery life, simplify magnetic alignment, and ensure reliable sensing in noisy, thermally demanding environments. Whether you need flexible pole detection or precise directional switching, these TMR solutions offer the performance and efficiency required to design smarter, longer-lasting applications, from smart meters and wearables to factory automation and home security systems.”