New LF21173TMR and LF21177TMR switches deliver high sensitivity, fast response, and extended battery life in a compact LGA4 package for smart, battery-powered electronics.
ROSEMONT, Ill, January 13, 2026 -- Littelfuse, Inc. (NASDAQ: LFUS), a diversified, industrial technology manufacturing company empowering a sustainable, connected, and safer world, today announced the launch of two next-generation omnipolar magnetic switches, the LF21173TMR and LF21177TMR. These devices combine Tunneling Magnetoresistance (TMR) and CMOS technologies in a compact LGA4 package, providing ultra-low power consumption, exceptional magnetic sensitivity, and fast response for compact, battery-powered systems. (View the video in English, Chinese, and Japanese)
Designed for operation across a wide voltage range (1.8 V–5.5 V), the LF21173TMR and LF21177TMR support multiple magnetic thresholds, enabling flexible integration into space-constrained applications such as smart meters, electronic locks, medical devices, and portable consumer electronics. Compared with conventional Hall-effect switches, these TMR devices deliver significantly higher sensitivity and lower power draw, helping engineers build smaller, more energy-efficient, and longer-lasting products.
“With the launch of the LF21173TMR and LF21177TMR switches, we’re bringing our customers a new level of precision and efficiency in magnetic sensing,” said Julius Venckus, Global Product Manager, Sensors at Littelfuse. “By integrating advanced TMR technology, this switch delivers ultra-low power consumption and high sensitivity—solving key challenges in compact, battery-powered designs. It’s a game-changer for engineers building smarter, more reliable devices in industrial, medical, and consumer applications.”
TMR Advantage
Unlike traditional hall-effect technology that relies on the hall voltage generated by magnetic flux, TMR sensors measure resistance changes in magnetic tunnel junctions, producing stronger signal output at much lower current levels. The result is a switch that consumes less power while maintaining excellent accuracy and thermal stability—ideal for energy-constrained applications where every microamp counts.
At-a-Glance: Key Features and Benefits
- Ultra-low power consumption extends battery life in portable devices.
- High magnetic sensitivity (9 – 30 Gauss) ensures reliable detection with smaller magnets.
- Wide 1.8 V–5.5 V operating range supports flexible system integration.
- Fast response time enables precise, real-time sensing.
- Compact LGA4 package fits space-constrained designs.
- Omnipolar operation detects both the north and south poles, simplifying the layout.
Markets and Applications
- Health care: continuous glucose monitors and drug delivery pens
- Building automation: smart gas and water meters
- Consumer electronics: robotic appliances and portable devices
- Industrial automation: industrial controls and electronic locks
- Transportation: e-bikes, two-/three-wheelers, and off-highway vehicles
The LF21173TMR and LF21177TMR expand the Littelfuse magnetic sensors portfolio, empowering engineers to design the next generation of compact, energy-efficient smart devices that seamlessly sense, respond, and perform with precision.
Frequently Asked Questions: LF21173TMR and LF21177TMR TMR Switches
- What is TMR technology, and how does it differ from hall-effect sensing?
Tunneling magnetoresistance (TMR) uses changes in electrical resistance to detect magnetic fields, offering higher sensitivity and lower power consumption than hall-effect sensors. TMR enables longer battery life and improved precision in compact devices. - What does “omnipolar” mean in a magnetic switch?
Omnipolar switches respond to both north- and south-polar magnetic fields. This function simplifies system design by eliminating the need for magnet orientation or polarity control during assembly. - What advantages does the compact LGA4 package provide?
The low-profile LGA4 package enables easy surface mounting and supports ultra-compact board layouts. Its small footprint is ideal for miniaturized or battery-powered designs where space and height are critical. - How do the LF21173TMR and LF21177TMR improve design efficiency?
Their high sensitivity allows the use of smaller or weaker magnets, while the compact LGA4 package saves valuable board space. This combination reduces component count, simplifies integration, and improves overall system efficiency. - Are these switches compatible with standard CMOS circuits?
Yes. The integrated CMOS output interface ensures easy connection with low-power logic circuits, making these TMR switches drop-in ready for a wide range of electronic designs.
Availability
They are available in tape-and-reel format in quantities of 3,000 pieces. Sample requests are accepted through authorized Littelfuse distributors worldwide. For a listing of Littelfuse distributors, please visit Littelfuse.com.
For More Information
Additional information is available on the LF21173TMR and LF21177TMR product pages. For technical questions, please contact: Julius Venckus, Global Product Manager, jvenckus@littelfuse.com.
About Littelfuse
Littelfuse, Inc. (NASDAQ: LFUS) is a diversified, industrial technology manufacturing company empowering a sustainable, connected, and safer world. Across more than 20 countries, and with approximately 16,000 global associates, we partner with customers to design and deliver innovative, reliable solutions. Serving over 100,000 end customers, our products are found in a variety of industrial, transportation, and electronics end markets–everywhere, every day. Learn more at Littelfuse.com.