Low-power TMR switches boost magnetic sensitivity

Two omnipolar magnetic switches, the LF21173TMR and LF21177TMR from Littelfuse, combine tunneling magnetoresistance (TMR) and CMOS technologies in a compact LGA4 package. Compared with conventional Hall-effect switches, these TMR devices offer higher sensitivity and lower power consumption, making them useful for energy-efficient designs.

Operating from 1.8 V to 5.5 V while consuming just 160 nA, the LF21173TMR and LF21177TMR deliver typical sensitivities of 10 Gauss and 30 Gauss, respectively. This high magnetic sensitivity ensures reliable detection even with smaller magnets, enabling more compact product designs without sacrificing performance.

Unlike Hall-effect sensors, which rely on voltage generated by magnetic flux, TMR sensors detect resistance changes in magnetic tunnel junctions. This approach produces stronger signal outputs at lower current levels, allowing engineers to create smaller, longer-lasting, and more energy-efficient devices—extending battery life in portable electronics.

Samples of the LF21173TMR and LF21177TMR are available through authorized Littelfuse distributors.

LF21173TMR product page 

LF21177TMR product page 

Littelfuse

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