Two next-generation Tunneling Magnetoresistance (TMR) magnetic switches, the LF21112TMR omnipolar switch and the LF11215TMR bipolar switch, were introduced by Littelfuse. These compact TMR switches provide energy-efficient sensing solutions for smart meters, wearables, consumer electronics, industrial automation, and home security systems because of their remarkable magnetic sensitivity, thermal stability, and extremely low power consumption.
Key Features and Benefits
Both devices are housed in compact SOT23-3 packages and feature:
- TMR technology for higher sensitivity and thermal stability
- Push-pull CMOS output for clean digital signals
- Schmitt trigger inputs to reduce noise and improve reliability
- Excellent immunity to external magnetic interference
- Wide operating voltage: 1.8V to 5.0V
Expanded TMR Sensor Portfolio
Both switches outperform conventional Hall-effect sensors and older magnetic switch technologies by combining TMR technology with ultra-low-power CMOS design.
The Littelfuse magnetic sensor range has significantly expanded into battery-sensitive and always-on applications with these advancements.
- LF21112TMR: The company’s first omnipolar TMR switch, capable of detecting both North and South magnetic poles, enables greater flexibility in magnet placement and simplifies design. With a typical current draw of just 200nA, it is ideal for ultra-low-power applications.
- LF11215TMR: A bipolar digital TMR switch that delivers high-speed, precision detection with ultra-low 5 µA current consumption and a high magnetic sensitivity of just 17 Gauss. It excels at more complex sensing applications that require directional detection.
These switches help engineers design smaller, smarter, and more energy-efficient products while reducing mechanical complexity and extending battery life.
Markets and Applications
These Innovative Switches Are Ideal For:
- Smart utility meters (gas, water, heat)
- Battery-powered wearables and IoT sensors
- Lid and cover detection in appliances and power tools
- Tamper detection in home and building automation
- Rotary and linear position sensing in light industrial and robotic equipment
Bipolar vs. Omnipolar: What’s the Difference?
Omnipolar switches, such as the LF21112TMR, trigger a response when exposed to either magnetic pole, making them ideal for space-constrained designs and applications where it is harder to control the magnet alignment. Bipolar switches, such as the LF11215TMR, are triggered by a specific magnetic polarity (typically North), and reset with the opposite polarity (South). This directional sensitivity is advantageous for applications needing rotational or directional sensing.
Leadership Comments
“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,” said Julius Venckus, Global Product Manager at Littelfuse. “Both switches integrate Tunneling 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.”
“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,” added Julius.
Availability
They are available in tape-and-reel format in quantities of 3000 pieces. Sample requests are accepted through authorized Littelfuse distributors worldwide.
For a listing of Littelfuse distributors, please visit Littelfuse.com.
Additional information is available on the LF21112TMR omnipolar switch and the LF11215TMR bipolar switch product pages.
