Murata Manufacturing has begun mass production of its MRMS166R and MRMS168R anisotropic magnetoresistance (AMR) sensors, designed for use in healthcare, wearable, and IoT devices. The MRMS166R is notable for being the first AMR sensor to offer a remarkably low average current consumption of just 20 nA while operating from a 1.2 V power supply, which helps extend battery life in systems powered by coin cells.
These sensors are solid-state magnetic components used for switching applications. They detect the presence or absence of a magnetic field and send an output signal that systems use to manage functions like switching between active and sleep modes. This contactless switching eliminates the need for mechanical parts, enhancing reliability and supporting compact, sealed designs.
Automatic switching between active and sleep modes is widely used in battery-powered devices to reduce standby power consumption and extend operating life. In healthcare, applications include capsule endoscopes and medical patches. Wearable devices, including AR glasses and wireless earbuds, as well as security-related IoT devices, such as door open/close detection systems and smart locks, also use this functionality.
These devices commonly use silver oxide coin batteries (typically 1.55 V), which impose constraints on both available capacity and operating voltage. AMR sensors used as magnetic switches must therefore minimize current consumption while maintaining stable operation at low voltage. Murata addressed these requirements through a redesign of the AMR sensor’s internal circuitry, enabling ultra-low current consumption and reliable operation down to 1.2 V. This significantly reduces battery consumption during standby operation, supporting device operation for more than two years in typical use.
Both devices are housed in a compact package measuring 1.0 × 1.0 × 0.4 mm (0.04 × 0.04 × 0.02 inches), making them suitable for space-constrained designs. The MRMS166R operates over a 1.2 to 3.6 V supply range (1.5 V typ.) with an average current consumption of 20 nA and a maximum current output of 1 mA. The MRMS168R operates over a 2.0 to 3.6 V supply range (3.0 V typ.), with an average current consumption of 80 nA and a maximum output current of 12 mA, providing higher output drive capability for devices requiring increased load current.
Murata will continue to expand its AMR sensor lineup and reduce power consumption to support longer operating times and enhanced functionality in medical, wearable, and IoT devices.
