Magnetoresistors

Overview

Product Specifications

Types:

AMR: Sensitivity ~3–5%/Oe, requires set/reset coils for linearity.

GMR: Sensitivity ~10–20%/Oe, used in hard disk drives (HDDs).

TMR: Highest sensitivity (~50–200%/Oe), ultra-low power (nA range), and wide temperature range (-40°C to +150°C)

Electrical Properties:

Operating Voltage: 1.8V–5V (typical for TMR).

Output: Analog (e.g., 0.5–2.5V) or digital (push-pull).

Physical Properties:

Packages: SOT-23, DFN, or custom modules.

Temperature Coefficient: ±0.1%/°C (TMR), ±0.3%/°C (AMR/GMR)

Product Grades

Standard Grade: AMR/GMR for industrial sensors (e.g., position detection).

High-Performance Grade: TMR for precision applications (e.g., medical imaging, aerospace).

Low-Power Grade: Nanopower TMR for IoT/wearables (e.g., 310nA standby current)

Coatings

None: Standard for AMR/GMR due to inherent corrosion resistance.

Epoxy: For mechanical protection in harsh environments (e.g., automotive).

Nickel/Gold: Enhances solderability for PCB-mounted TMR modules

Applications

Automotive: Wheel speed sensors (ABS), current sensing in EVs.

Data Storage: HDD read heads (GMR/TMR).

Consumer Electronics: Smartphone compasses (AMR), smart locks (TMR).

Industrial: Robotics (position feedback), angle encoders

FAQs

How does TMR compare to Hall sensors?

TMR offers >50x higher sensitivity and nA-level power but at higher cost

Can MRs measure static (DC) fields?

Yes, AMR/TMR detect DC fields, unlike inductive sensors

Why choose GMR over AMR?

GMR has wider linearity and no need for set/reset coils

Temperature sensitivity?

TMR has minimal drift (±0.1%/°C); AMR/GMR may need compensation circuits

Customization lead time?

Typically 6–8 weeks for TMR due to thin-film deposition complexity