Murata’s latest move into ultra-low power magnetic sensing feels like one of those quiet but important infrastructure shifts in wearable and medical electronics that you only really appreciate once you think about where the bottlenecks actually are.
Murata Manufacturing Co., Ltd. (TOKYO: 6981, ISIN: JP3914400001) has started mass production of its MRMS166R and MRMS168R anisotropic magnetoresistance (AMR) sensors, targeting healthcare, wearables, and IoT applications where every nanoamp matters and battery chemistry is already being pushed to its limits. What stands out immediately is the MRMS166R, which is described as the first AMR sensor to operate at an average current consumption of just 20 nA while running from a 1.2 V supply. That combination is unusually aggressive even by modern ultra-low-power standards, and it directly addresses a constraint that shows up in real-world devices more than in datasheets: coin cell batteries don’t just limit capacity, they also tightly constrain voltage headroom as they age.
These are solid-state magnetic switching sensors, meaning they don’t measure continuous analog fields for high-resolution sensing but instead act more like intelligent on/off triggers. They detect the presence or absence of a magnetic field and translate that into a logic-level output that system controllers can use to manage state transitions, like waking a device from sleep or putting it back into deep standby. It sounds simple, almost trivial, but in practice this is exactly the kind of mechanism that determines whether a device lasts months or years in the field, especially in sealed systems where battery replacement is either impossible or undesirable.
The design choice to optimize for standby switching is particularly relevant in healthcare and wearable use cases. Capsule endoscopes, medical patches, AR glasses, wireless earbuds, and small IoT security devices like smart locks all rely on long idle periods punctuated by short bursts of activity. In those idle periods, even tens of nanoamps accumulate into meaningful energy loss over time, so reducing standby current becomes more impactful than marginal gains in processing efficiency. Murata’s redesign of the internal circuitry to enable stable operation down to 1.2 V is essentially about squeezing usable life out of silver oxide coin cells, which typically sit around 1.55 V but degrade in both voltage and capacity over time.
The MRMS166R and MRMS168R are also physically tiny, at just 1.0 × 1.0 × 0.4 mm, which makes them suitable for designs where mechanical switching is impossible simply because there is no room left on the PCB. The two parts are differentiated mainly by power and drive capability. The MRMS166R is the ultra-low-power variant with 20 nA average current and a 1 mA max output, optimized for minimal drain in constrained systems. The MRMS168R, by contrast, operates at a slightly higher 80 nA average current and supports up to 12 mA output current, making it more suitable for applications that need to drive heavier loads or interface with more demanding circuitry.
What Murata is really doing here, beyond the product specs, is continuing a broader trend in IoT and medical electronics where the “sensor” is no longer just a measurement component but part of a full power-state architecture. The system-level implication is that more devices can remain sealed, smaller, and more autonomous, while still achieving multi-year lifespans without battery replacement. That doesn’t sound dramatic on paper, but in practice it’s one of the enabling layers behind everything from disposable diagnostics to always-on wearable monitoring.
Murata, as a company, sits comfortably in that background infrastructure role. It’s not usually the brand users see, but it’s often the one defining what is physically and electrically possible inside the devices they interact with every day.