The design of modern electric vehicles and automated factories has created a difficult environment for traditional sensors. As we pack high-voltage cables and powerful motors into tighter spaces, the resulting electromagnetic interference becomes a significant hurdle. In safety-critical systems like electronic braking or steer-by-wire, even a minor measurement error caused by a nearby magnetic field can lead to system failure.

The Problem with External Fixes

For a long time, the industry relied on physical shielding to protect sensors from these “stray” fields. While a metal shield can work, it is often a clumsy solution. It adds weight and volume to a component that needs to be as small as possible. Furthermore, shields can saturate if the external field is too strong, and their performance often shifts as temperatures change. For engineers, this adds another layer of complexity to an already difficult assembly process.

Why Integrated Immunity is Different

At Piher, we take a different approach. Instead of trying to block the interference with a physical barrier, we design the sensor architecture to ignore the noise entirely. This is achieved through two primary methods that focus on the physics of the magnetic field itself.

1. Vertical Sensitivity and Differential Sensing

One of the most effective ways to handle interference is to limit what the sensor actually “sees.” Many of our sensors are designed to be sensitive primarily to magnetic fields in the Z-direction (vertical to the chip surface). By ignoring horizontal influences, we eliminate a large portion of ambient noise.
To handle vertical interference, we use a differential sensing layout. The chip contains multiple sensing elements that measure the magnetic field at different points. Because a stray field is typically uniform across the small area of the sensor, it hits every element with the same strength. Our internal logic subtracts this common noise, leaving only the precise signal from the target magnet.

2. High-Frequency Inductive Technology

In environments where magnetic noise is extreme, such as directly inside an electric motor, we often move away from magnets entirely. Our inductive sensors use high-frequency electromagnetic coupling. Because these sensors operate at frequencies much higher than the interference generated by vehicle drivetrains, the noise simply does not register. It is a natural, physical immunity that does not require extra parts or specialized materials.

The Practical Value for Your Project

Moving the immunity inside the sensor provides several immediate benefits for the production line and the end user:

Lighter, Smaller Designs: Without the need for bulky metal shields or oversized magnets, you can fit precise sensing into much smaller housings

Predictable Performance:

Since the immunity is built into the silicon and the circuit design, it remains stable across the entire temperature range and the life of the product.

Simplified Supply Chains:

Reducing the number of components in an assembly means fewer parts to source, test, and install.

Safety Compliance:

Our sensors are built to support the rigorous requirements of ISO 26262 and ASIL-rated systems, providing the data integrity needed for autonomous and semi-autonomous functions.
By solving the challenge of stray fields at the component level, Piher allows engineers to focus on the broader system design without worrying about electromagnetic interference.

Optimize Your Next Design

If you are currently dealing with interference issues or looking to reduce the footprint of your sensing assemblies, we can help you find the right technology for your application.

Contact our engineering team today to discuss your technical requirements and request a sample for your prototype.

With decades of experience designing sensors for a wide range of industries, our global manufacturing network is built for agility. We are able to meet tight deadlines, adapt to supply chain challenges, and deliver solutions wherever they’re needed.