Features and Benefits

 Tunneling Magnetoresistance (TMR) Technology

 Large Output Signal Without Amplification

 Compatible with Wide Range of Supply Voltages

 High Resistance for Low Power Consumption

 Wide Airgap Tolerance

 Excellent Thermal Stability

 Very Low Hysteresis

 Ultrasmall Package

Applications

 Rotary Position Sensors

 Rotary Encoders

 Contactless Potentiometers

 Valve Position Sensors

 Knob Position Sensors

General Description

The output voltage of the MMA243F TMR angle sensor is proportional to the sine or cosine of the

angle of a magnetic field applied parallel to the surface of the sensor, which can be provided by a

small magnet positioned above the device. The MMA243F includes two Wheatstone bridges, which

can be configured to output sine and cosine functions respectively. Each bridge includes four TMR

sensor elements in a push-pull arrangement to produce a best-in-class peak-to-peak signal as large

as 80% of the supply voltage, eliminating the need for amplification in many applications.

Additionally, the unique TMR Wheatstone bridge technology accurately compensates the output

against changes in ambient temperature. This sensor is assembled in an ultra small LGA8 package

of 3.0 mm  3.0 mm  0.75 mm.

Operation

A small magnet, placed above the MMA243F, can be used to provide a magnetic field in any

desired orientation parallel to the plane of the MMA243F package. The magnetic field is detected

by TMR sensors in the MMA243F that are composed of two magnetic layers. One layer of the

TMR sensors is a “pinned layer” that is not affected by the magnetic field, and the other is “free

layer,” which has a magnetization that aligns parallel to the applied magnetic field. Because the

TMR effect produces a resistance that is proportional to the sine or cosine of the relative difference

between the free and pinned layer magnetization orientations, the sensor output voltage is

sinusoidally dependent on the angle of the applied magnetic field, thereby providing a measure of

the orientation of the magnet.