New omnipolar and bipolar devices combine high sensitivity, thermal stability, and minimal power draw for compact, battery-powered electronics.
Littelfuse has introduced two next-generation Tunneling Magnetoresistance (TMR) switches—the LF21112TMR omnipolar and LF11215TMR bipolar magnetic switches—designed for smart meters, IoT sensors, wearables, and other low-power systems that rely on reliable magnetic detection.
Smarter Sensing for Power-Sensitive Designs
By pairing TMR technology with an ultra-low-power CMOS design, Littelfuse delivers a significant leap in efficiency compared to legacy Hall-effect sensors. The result is greater magnetic sensitivity, tighter thermal stability, and drastically lower current consumption—ideal for always-on and battery-sensitive applications.
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LF21112TMR (Omnipolar): Detects both North and South poles for flexible magnet placement and simplified design integration. Draws just 200 nA, making it one of the lowest-power magnetic switches on the market.
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LF11215TMR (Bipolar): Offers directional detection and higher precision with only 1.5 µA of current consumption and 17 Gauss magnetic sensitivity—perfect for applications requiring pole-specific triggering.
Compact, Reliable, and Noise-Resistant
Both models are housed in SOT23-3 packages and feature:
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TMR architecture for higher sensitivity and thermal stability
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Push-pull CMOS output for clean digital signaling
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Schmitt trigger inputs for noise immunity
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Operating voltage range from 1.8 V to 5.0 V
Engineers can expect easier integration, smaller footprints, and extended battery life—all without sacrificing signal accuracy or environmental robustness.
Applications Across Smart and Industrial Markets
The new switches are well-suited for:
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Smart utility meters (gas, water, and heat)
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Wearables and IoT sensors
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Appliance lid or cover detection
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Tamper detection in security and building systems
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Position sensing in light industrial and robotic equipment
Why TMR Over Hall-Effect?
TMR magnetic switches deliver higher magnetic sensitivity and up to 90% lower power consumption than Hall-effect sensors, enabling smaller, smarter, and longer-lasting products. Omnipolar options simplify alignment for space-constrained designs, while bipolar versions provide directional control for motion and rotation detection.
Both devices can often replace Hall-effect sensors directly thanks to their standard SOT23-3 footprint and compatible electrical characteristics, giving engineers a simple path to improved performance.
