Littelfuse Expands Its Magnetic Sensor Portfolio with Two Next-Generation TMR Switches
November 11, 2025 — Littelfuse, Inc. (NASDAQ: LFUS), an industrial technology manufacturing company committed to building a sustainable, connected, and safer world, today announced the release of two new Tunnel Magnetoresistance (TMR) magnetic switches: the LF21112TMR unipolar switch and the LF11215TMR bipolar switch.
These compact devices deliver exceptional magnetic sensitivity, thermal stability, and ultra-low power consumption—ideal for smart metering, wearables, consumer electronics, industrial automation, and home security systems.
(Watch the product video—available in English, Chinese, and Japanese.)
Expanding the TMR Sensor Lineup
By combining advanced TMR technology with ultra-low-power CMOS design, these new switches deliver significantly improved performance over traditional Hall effect sensors and older magnetic switch technologies.
The launch marks a major expansion of Littelfuse’s magnetic sensing portfolio into ultra-low-power and normally-off applications.
LF21112TMR – The company’s first omnipolar TMR switch, capable of detecting both north and south magnetic poles. With a typical current consumption of only 200 nA, it is perfectly suited for ultra-low-power designs.
LF11215TMR – A bipolar digital TMR switch offering high-speed and high-precision detection, ultra-low power draw (1.5 µA), and magnetic sensitivity up to 17 Gauss—ideal for directional and rotational sensing.
Omnipolar vs. Bipolar Switching
Omnipolar switches like the LF21112TMR respond to either magnetic pole, offering greater design flexibility and simplifying magnet alignment in space-constrained applications.
Bipolar switches such as the LF11215TMR, on the other hand, are triggered by one polarity (typically north) and reset by the opposite (south), making them ideal for applications that require precise directional or rotational sensing.
Key Features and Benefits
• Both devices are housed in a compact SOT23-3 package and feature:
• High magnetic sensitivity and thermal stability enabled by TMR technology
• Push-pull CMOS output for clean digital signal output
• Schmitt trigger input for noise immunity and reliability
• Excellent resistance to external magnetic interference
• Wide operating voltage range: 1.8V to 5.0V
These advantages help engineers design smaller, smarter, and more energy-efficient products—reducing mechanical complexity while extending battery life.
Target Markets and Applications
• These innovative TMR switches are well suited for:
• Smart utility meters (gas, water, heat)
• Battery-powered wearables and IoT sensors
• Appliance door and lid detection
• Tamper detection in home and building automation
• Rotational and linear position sensing in light industrial and robotics equipment
Engineering Perspective
“With the introduction of the LF21112TMR and LF11215TMR, Littelfuse expands its TMR sensor portfolio to address the growing demand for compact, battery-powered, always-on devices,” said Julius Venckus, Global Product Manager at Littelfuse.
“By combining tunnel magnetoresistance (TMR) technology with ultra-low-power CMOS architecture, these sensors achieve exceptional sensitivity and thermal stability at industry-leading current levels—only 200 nA for omnipolar detection and 1.5 µA for bipolar detection.
This innovation empowers engineers to extend battery life, simplify magnet alignment, and ensure reliable performance in demanding thermal and noisy environments.”
Frequently Asked Questions
Q1: How do TMR switches compare to Hall effect sensors?
TMR switches provide higher magnetic sensitivity and dramatically lower power consumption. This makes them ideal for compact, battery-operated applications such as smart meters and wearables, where reliability and efficiency are critical.
Q2: What’s the difference between omnipolar and bipolar switches?
Omnipolar switches (e.g., LF21112TMR) respond to either magnetic pole, simplifying magnet placement. Bipolar switches (e.g., LF11215TMR) activate with one pole and reset with the opposite, enabling precise directional or rotational sensing.
Q3: Why are these ideal for battery-powered and IoT devices?
Their ultra-low current consumption—just 200 nA for omnipolar and 1.5 µA for bipolar models—makes them perfect for energy-sensitive devices. The CMOS design ensures fast response and extended battery life.
Q4: Can they replace Hall effect sensors in existing designs?
Yes. Both models can often be directly integrated into existing Hall sensor circuits without major redesign. Their push-pull CMOS outputs, standard SOT23-3 packaging, and broad voltage range simplify replacement while improving sensitivity and efficiency.
Availability
The LF21112TMR and LF11215TMR TMR magnetic switches are available in tape-and-reel packaging (3,000 units per reel). Samples can be requested through authorized Littelfuse distributors worldwide.