Magnetic sensing is becoming increasingly important in modern electronic systems, particularly in motion control, power conversion, and protection applications, where contactless measurement of position and current is essential. These signals directly influence control quality, system efficiency, and how quickly protection mechanisms can respond.

Across consumer, industrial, and automotive domains, designs are moving toward smaller form factors, faster switching and control loops, and higher accuracy requirements. However, these trends introduce new challenges. As systems shrink, the available magnetic signal becomes weaker. Faster operation increases susceptibility to electrical noise, while tighter performance targets leave less margin for error.

Tunnel magnetoresistance (TMR) technology addresses these challenges by combining high sensitivity, low noise, and strong intrinsic signal output, enabling reliable sensing even under demanding conditions[1].

This article introduces the fundamentals of TMR sensing and shows how Infineon applies this technology in practical solutions for accurate and robust magnetic field measurement. Application examples include position sensing in compact user interfaces, coreless isolated current sensing for power conversion and motor drives, and ultra-fast overcurrent protection in high-voltage solid-state systems.

Together, these examples demonstrate how Infineon’s XENSIV™ magnetic sensor based onTMR portfolio[2] enables scalable, high-performance sensing solutions across consumer, industrial, and safety-relevant applications.

Table of contents

1. Why magnetic sensing is evolving in modern systems

Magnetic sensing in modern electronic systems enables contactless measurement of motion (position or angle) and electrical load (current). It is becoming increasingly relevant wherever compact designs, electrification, and fast electronic control converge.

In consumer devices such as gaming accessories and wearables, magnetic sensors deliver precise and consistent user input,for example in joysticks, triggers, and key switches,while supporting low-power operation. They also enable power-efficient system behavior, such as detecting inactivity and switching devices into lower-power modes, thereby extending battery life.

In industrial and power applications,including power tools, drones, and energy storage systems,magnetic sensing enables accurate, contactless measurement of rapidly changing currents. This improves motor control and enhances the efficiency of power conversion systems.

In protection systems such as solid-state relays, smart circuit breakers, and battery management systems, current sensing enables fast detection of abnormal conditions, allowing systems to respond quickly and prevent damage.

In automotive and other safety-critical motion control systems, magnetic sensors are widely used for position and angle measurement, supporting reliable closed-loop control and enabling diagnostic functions that enhance system safety.

Across these domains and many beyond, the need for improved sensing performance is driven by three key trends:

1. Size:Smaller designs and tighter packaging reduce available magnetic signal and increase sensitivity to variation

1. Speed:Faster switching wide bandgap technologies and control loops require higher bandwidth and low-latency sensing

1. Accuracy:Stricter control targets and safety requirements reduce acceptable margins for error and drift

These trends introduce a common set of challenges:

Detecting weaker signals in compact designs Maintaining stable measurements in electrically noisy environments Responding quickly enough for control and protection tasks Ensuring reliable performance without extensive calibration or compensation

TMR technology directly addresses these challenges by providing high sensitivity, low noise, and strong output signals. By improving signal quality at the source, it reduces reliance on complex external signal conditioning and enables compact, scalable high-performance sensing solutions.

2. Understanding magnetic sensing technologies in system design

Magnetic sensing technologies form the interface between physical signals and system-level decision making. As system requirements become more demanding, understanding how different sensing principles behave at the device and system level becomes critical for selecting the right solution.

2.1Overview of magnetic measurement principles

Magnetic sensing technologies can be broadly grouped into Hall-effect and magnetoresistive(MR) approaches. Hall-effect sensors convert magnetic fields into voltage signals through charge-carrier deflection and provide robust, cost-effective solutions for general sensing tasks.

Magnetoresistive technologies, which include anisotropic magnetoresistance (AMR), giant magnetoresistance (GMR), and tunneling magnetoresistance (TMR), convert magnetic field changes into resistance variations, enabling higher sensitivity and improved resolution. Among these, TMR offers particularly strong signal output and superior signal-to-noise ratio(SNR)[2].

Figure 1: Magnetic sensing technology overview and comparison (FL: Free Layer, TB: Tunnel Barrier, RL: Reference Layer, AF: Anti-Ferro Magnet, PL: Pinned Layer, NML- Non-magnetized layer)

At the device level, TMR sensors rely on a structure consisting of two ferromagnetic layers separated by a thin insulating barrier. Changes in the magnetic field alter the relative alignment of the magnetization directions in the free and reference layers, resulting in a measurable change in resistance.

At the system level, this stronger intrinsic signal and lower noise are critical advantages, because they reduce the need for external amplification and filtering while improving robustness in compact and electrically noisy environments.

While these characteristics define the fundamental advantages of TMR as a sensing technology, their practical impact depends on how the sensor is operated within a system. In real applications, TMR sensors are configured differently depending on whether the goal is to extract directional information, such as angle, or to measure the magnetic field strength directly. This distinction leads to the two primary operating modes of TMR sensors,saturation mode and linear mode,which are discussed in the next section.

2.2Saturation vs. linear operation in TMR sensors

TMR sensors can be configured based on whether the application needs field direction (angle) or field strength (linear measurement). Angle sensors measure sine and cosine angle components with monolithically integrated magnetoresistive elements. In linear measurement for power systems, XENSIV™ TLI5572 for example[6]is used as miniature linear magnetic sensors for coreless current sensing of bi-directional AC and DC currents.

This difference (see Table 1) is significant at system level because the key design priorities differ between angle and linear sensing.

Table1.Angle (direction) sensing vs. linear field measurement in MR/TMR sensors

2.3Infineon’s XENSIV™ Vortex-based TMR structures: Improving linearity and cross-field robustness

In compact and densely integrated systems, the limiting factor for sensing devices is often not raw sensitivity, but how consistently they behave when real-world disturbances occur. This applies across a wide range of applications, including compact interfaces such as gaming controls, wearables, and other space-constrained designs. Cross-fields, mechanical tolerances, and limited magnetic headroom can all translate into non-ideal output behavior and unit-to-unit variation.

These challenges are particularly relevant for linear-mode sensing, where the output must follow the absolute magnetic field strength and is therefore more sensitive to disturbances. Conventional TMR structures offer only a limited usable linear range, which has historically constrained robust linear sensing.

Figure 2: Magnetic sensing technology overview and comparison (FL: Free Layer, TB: Tunnel Barrier, RL: Reference Layer, AF: Anti-Ferro Magnet, PL: Pinned Layer, NML- Non-magnetized layer)

Vortex-based TMR addresses this by forming a stable closed-flux magnetization structure, enabling a more controlled and predictable response to external magnetic fields. This results in:

Wider usable magnetic range up to ±100 mT[2] Improved linearity, with errors below 0.5% in relevant applications Significantly reduced cross-field sensitivity, with up to 100× improvement Stable output behavior, minimizing hysteresis and discontinuities

These characteristics are critical in compact sensing environments, where mechanical variation and external interference can affect measurement accuracy. At the same time, they enable reliable linear-mode operation forcurrent sensing applications, where accurate field-proportional measurement is essential.

2.4 Monolithic CMOS + TMR integration: Enabling compact, application‑ready sensing

While vortex structures improve linear sensing at the device level, practical system performance depends on how effectively the sensing signal is processed and integrated into the signal chain.

In many designs, the sensing element is only part of the challenge. The larger system effort lies in maintaining signal integrity through PCB routing, switching noise, interface constraints, and integration into control or protection logic. This is especially critical in linear-mode sensing, where the signal depends directly on magnetic field strength.

A key development addressing these challenges is Infineon’smonolithic CMOS + TMR integration, which brings sensing and signal-processing functions together on a single die. By integrating more of the signal chain into the sensor itself, this approach reduces the need for external circuitry and improves robustness.

At the system level, this enables:

improved signal integrity through shorter internal signal paths reduced external amplification and filtering requirements increased robustness to noise and environmental variation more compact and efficient system design.

Taken together, these developments enable TMR technology to translate into application-ready sensing solutions.Table 2 provides an overview of the latest products, an extension of Infineon’s XENSIV™ TMR-based magnetic sensors portfolio across key domains and system-level requirements[2].

Table2.XENSIV™ TMR sensor portfolio for key application domains

For more detailed product information and reference designs, explore the XENSIV™ current sensors selection guide and XENSIV™ magnetic position sensors selection guide.

3. Enabling high-performance sensing in applications with TMR

Modern electronic systems rarely use sensing as a stand‑alone function. In motor drives, robotics, battery-powered tools, and power conversion stages, sensor outputs directly feed control and protection loops that must remain stable under fast transients and electrically noisy conditions. In these environments, improving signal quality at the sensing point is often the most effective way to reduce downstream complexity and preserve accuracy across operating conditions.

These capabilities are closely linked to advances in linear-mode TMR sensing discussed in Section‎2, which enable accurate and robust magnetic field measurement in real-world environments.

The following examples are illustrative rather than exhaustive, highlighting where TMR-based sensing brings tangible system-level value across industrial, consumer, and safety-relevant applications.

3.1Position sensing in compact interfaces (gaming and wearables)

Compact input devices,especially gaming controllers and wearables,have less mechanical space, tighter power budgets, and higher expectations for consistent feel over lifetime. In these geometries and form factors,small displacements and packaging constraints can introduce unwanted magnetic field components, which may lead to non-ideal transfer behavior such as drift in center position or inconsistent actuation.

3 a)

Figure 3a: a) Joystick/thumb-stick sensing can be realized either with two 1D sensors for X/Y tilt (e.g., XENSIV™ TLI55910/50) or with a single 2D TMR sensor for integrated X/Y tilt (XENSIV™ TLV552D) (Top)

3 b)

Figure 3b:Functional block diagram of a gaming controller architecture (Down)

In gaming and PC-peripheral designs, XENSIV™ TLI55910/50 linear magnetic devices are commonly positioned for thumb‑stick and joystick sensing, while XENSIV™ TLI55910 is also referenced for applications such as mouse click or press detection. Both XENSIV™ TLI55910 and TLI55950 are associated with keyboard single-key sensing and other compact input interfaces. More broadly, these sensing approaches extend to wearable devices where low power and stable operation are important considerations.

At the device level,XENSIV™ TLI55910 enables a high-sensitivity, low-power linear TMR position sensor suited for battery-powered devices and stable operation in harsh environments, while XENSIV™TLI55950 sensor builds on this by offering an amplified output, enabling higher signal levels and improved signal usability in high-sensitivity applications[1],[5],[2].

Feature-to-benefit summary

Low power and compact integration:

XENSIV™ TLI55910 linear sensor is highlighted with ~0.25 mA current consumption and a compact SOT23 package, supporting battery-powered gaming interfaces and wearables where low power and space matter.

Linearity and cross-field robustness:

XENSIV™ TLI55910/50 sensors are high SNR analog 1D TMR sensors with high linearity and cross-field robust behavior enabled by Vortex TMR technology. A separate storyline summary also emphasizes Vortex TMR delivering superior linearity and strong cross-field robustness for consistent performance.

Amplified-output option(when more signal level is needed):

XENSIV™ TLI55950 is a linear TMR sensor with amplified output and is associated with high sensitivity and ultralow noise. The selection guide also lists example target applications such as power tool trigger detection, service robots and drones angle sensing, and high-precision dual-encoder setups.

Design recommendation

Lowest power / smallest footprint:useXENSIV™ TLI55910 linear sensor Consistency in compact mechanics:use XENSIV™ TLI55910/50 linear sensors (Vortex TMR) for better linearity and cross‑field robustness Higher output signal needed:useXENSIV™ TLI55950 linear sensor(amplified output)

The same need for compact, repeatable sensing also shows up in many industrial joystick and operator-control designs, making these approaches relevant beyond consumer devices.

Use cases:thumb-stick/joystick, key-switch, wearables, industrial control interfaces, mouse press

3.2 Coreless current sensing for power and motion systems(power tools, robotics,fans,energy)

Fast-switching power stages and compact motor drives are placing increasing demands on current sensing: higher di/dt, stronger electromagnetic interference (EMI), tighter space constraints, and limited thermal headroom. In these environments, sensing accuracy and response speed directly affect system performance. Coreless magnetic current sensing addresses these challenges by keeping the sensing element physically separate from the current path. This enables contactless, galvanically isolated current measurement without introducing insertion losses, while still maintaining accuracy across a wide current range. High bandwidth supports fast control loops, and low-noise behavior helps ensure stable operation under electrically noisy conditions.

Figure 4: Coreless current sensing with XENSIV™ TLx5572 current sensor on an external current rail: analog output (AOUT) routed to an MCU ADC for fast control and monitoring

These requirements are particularly relevant in industrial energy and power conversion systems,including PV inverters and energy storage,where current measurement directly influences system efficiency, control stability, and protection response.

In closed-loop motor control, current feedback determines torque response and overall system stability. This makes bandwidth, noise, and latency practical design constraints,especially in compact drives and fast-switching power conversion stages. Coreless sensing approaches help address these needs by combining isolation with the bandwidth and signal quality required for reliable, high-speed control loops.

In humanoid robot actuators, external‑rail current sensing can serve as a practical alternative to shunt-based approaches. Magnetic TMR current sensors mounted above external current rails enable a compact, isolated, and low‑loss method for in‑phase current measurement, supporting efficient and responsive motion control in high‑dynamic actuator systems.

In typical implementations, the sensor output is routed as an analog signal (AOUT) to an MCU’s ADC for control and monitoring, as illustrated in the XENSIV™ TLx5572 application diagram.

​​Feature-to-benefit summary

High-dynamic current feedback:

XENSIV™ TLI5572 current sensor devices enable coreless current sensing for bi-directional AC/DC

measurement in applications with fast current changes[6] Application focus:

Used in power tools, robotics, industrial pumps & fans (motor control), AC compressors, induction cooktops and fast-switching GaN/SiC power stages and converters (e.g. in server, telecom rectifier and photovoltaic) Key capabilities:

Support isolated current measurement from PCB-level to >kA, with MHz-class bandwidth, low-noise analog output, and operation from −40°C to 150°C. Scalability and efficiency:

One sensing concept can scale from PCB traces to busbars, while avoiding insertion losses and parasitic inductance. Precision and system integration:

XENSIV™ TLI5570 current sensor adds overcurrent detection support, configurable sensitivity, and

functional safety alignment (ASIL B as SEooC)[7].

Design recommendations

Fast control loops / high dynamics:useXENSIV™ TLI5572 current sensor(bandwidth, isolation, low noise) Scaling across power levels:use XENSIV™ TLx5572 current sensor approach from PCB to busbar Precision / safety features needed:considerXENSIV™ TLI5570 current sensor External‑rail sensing:validate geometry early

Use cases:Cost-efficient motor drives in power tools, robotics, pedelecs and drones; fast-switching GaN/SiC drive stages and power conversion; scalable platforms from PCB-level currents to busbar-level currents; external-rail sensing concepts for robotics actuators validate via simulation workflows; PV inverters and energy storage systems.

3.3Overcurrent protection in solid-state systems (eFuse, solid‑state relay, smart circuit breaker)

Figure 5: Generic block diagram of DC SSCB

Solid‑state protection turns fault handling into a timing problem: overcurrent must be detected quickly and the power path interrupted before damage propagates. This is particularly relevant in high‑voltage(HV)solid‑state protection and power distribution systems such as HV eFuses and solid‑state circuit breakers (SSCBs), where current sensing and protection logic must remain reliable in fast‑switching environments.‎Figure 5 illustrates a generic DC SSCB architecture to provide system context[8].

Feature-to-benefit summary

Integrated sensing and protection:

XENSIV™ TLE5571 current sensor combines coreless TMR current sensing with integrated overcurrent detection (OCD), enabling fast response times required in protection applications. Differential measurement for robustness:

The device uses two integrated TMR full bridges for differential field measurement, improving stability in electrically noisy environments. Bandwidth for fast transients:

With a minimum bandwidth of 2.5 MHz, the sensor supports fast transient detection in SiC/GaN-based systems with high switching speeds. Efficiency-oriented system behavior:

Coreless sensing avoids additional resistance and parasitic inductance, supporting efficient system

operation while reducing the risk of false OCD triggering. Implementation context:

The HV eFuse reference design positions XENSIV™ TLE5571 sensor within a high-side switching

architecture, supported by design documentation covering snubber/pre-charge, control logic, and auxiliary power supply integration Implementation context:

The HV eFuse reference design positions XENSIV™ TLE5571 sensor within a high‑side switching architecture, supported by design documentation covering snubber/pre‑charge, control logic, and auxiliary power supply integration.

Design recommendations

Fast overcurrent detection in HV protection:

Use a coreless current sensor with integrated OCD and differential measurement, as represented by XENSIV™ TLE5571 sensor in eFuse/SSCB architectures.

Fast‑switching, high power density environments:

Select devices with MHz‑class bandwidth and minimal parasitic impact to handle rapid transients in SiC/GaN systems.

Use cases:HV eFuses, solid-state relays, smart circuit breakers / solid-state circuit breakers, and HV power distribution protection systems requiring fast fault detection in fast-switching environments.

3.4Safety-oriented position sensing (automotive and industrial drives)

Safety-relevant motion control relies on position sensors that support functional-safety concepts and maintain reliable angle feedback in applications such as electric power steering (EPS). If angle feedback becomes inaccurate, the control system can apply incorrect assist torque, potentially affecting vehicle stability.

To meet these requirements, redundant sensor architectures are used. Single-die devices such as XENSIV™ TLE5501 achieve ASIL D through diagnostic coverage and internal redundancy (fail-safe operation), while dual-die solutions such asXENSIV™TLE5502Dintegrate independent sensing elements with separate signal paths to enable fail-operational designs[2].

Figure 6: Fail-operational rotor/angle sensing concept using redundant sensing paths: a dual-die sensor provides independent signal paths to two controllers, supporting high-availability system designs with XENSIV™ TLE5502D dual-die concept

Figure 6 shows a fail‑operational rotor/angle sensing concept using redundant signal paths. In this approach, a dual‑die sensor provides independent outputs to two controllers, supporting high‑availability system designs based on the XENSIV™TLE5502D concept. This unlocks significant cost-saving potential, as fail-operational applications can be achieved using a single sensor.

4. Conclusion

Magnetic sensing is being pushed into smaller, faster, and noisier systems across consumer, industrial, and automotive domains. In this environment, tunnel magnetoresistance (TMR)addresses this by delivering strong signal quality at the sensing point,supporting compact position sensing and high-dynamic current sensing, while reducing insertion losses through coreless, contactless measurement approaches.

At the device level, Infineon’s XENSIV™ Vortex TMR approach improves linearity and cross-field robustness for compact interface sensing, enabling more stable thumb-stick and joystick implementations using sensors such as XENSIV™ TLI55910/50, and extending these capabilities to 2D sensing with XENSIV™ TLV552D.

In power and motion systems, XENSIV™ current sensors such as TLI5570 and TLI5572 enable coreless, galvanically isolated current measurement with the bandwidth and low-noise performance required for fast control loops and wide bandgap power stages. For protection applications, the XENSIV™ TLE5571 combines differential sensing with integrated overcurrent detection and MHz-class bandwidth to support fast response in HV solid-state power systems such as eFuses and solid-state circuit breakers. In safety-oriented motion control, redundant sensor architectures and safety-ready designs,such as dual-die implementations,support fail-operational concepts and alignment with functional safety standards such as ISO 26262.

Taken together, these examples show how XENSIV™ magnetic sensing enables scalable sensing solutions for next-generation systems, from compact user interfaces to high-power drives, solid-state protection, and safety-critical motion control.

References

1. Zitong Zhou; Kun Zhang;Qunwen Leng, “_Tunneling Magnetoresistance (TMR) Materials and Devices for Magnetic Sensors,” in Spintronics: Materials, Devices, and Applications_, Wiley, 2022, pp.51-92;Available online

1. Infineon Technologies AG:_XENSIV™ Sensors– Product selection guide (2026);_Available online

1. Infineon Technologies AG:_XENSIV™TLE5502D TMR-based angle sensor datasheet_;Available online

1. Infineon Technologies AG:_XENSIV™TLI55910 TMR-based linear sensor datasheet_;Available online

1. Infineon Technologies AG:_XENSIV™TLI55950 TMR-based amplified linear sensor datasheet_;Available online

1. Infineon Technologies AG:_XENSIV™TLI5572 TMR-based current sensor datasheet_;Available online

1. Infineon Technologies AG:_XENSIV™ TLI5570 TMR-based current sensor product brief_;Available online

1. Infineon Technologies AG:_XENSIV™TLE5571 coreless Current Sensor in HV eFuse user manual;_ Available upon request