AL700 family AMR FixPitch sensors for angle and length measurement

The sensors in the AL700 family are FixPitch sensors based on the anisotropic MagnetoResistive (AMR) effect. 

The sensors offer

  • Extremely low harmonic output signals and non-contacting measurement
  • Pole adjustment to the magnetic pole pitch
  • Excellent accuracy by averaging across several poles
  • High tolerances for the working distance

This product family has six sensor variants for you to choose from.

  • AL795 FixPitch sensor for pole pitches of 0.5 mm
  • AL798 FixPitch sensor for pole pitches of 1.0 mm
  • AL796 FixPitch sensor for pole pitches of 2.0 mm
  • AL797 FixPitch sensor for pole pitches of 2.5 mm
  • AL794 FixPitch high-resistance sensor for pole pitches of 2.5 mm
  • AL780 FixPitch sensor for pole pitches of 5.0 mm

The sensors are FixPitch sensors that can be used on a fixed magnetic pole pitch.

The sensor design is based on PerfectWave technology which improves the signal quality by suppressing the harmonics.

Most sensors feature a PurePitch design. The magnetic fields of measurement scales are averaged out over several poles, allowing higher levels of accuracy to be achieved.

Suitable for absolute or incremental applications (linear or rotary motion) e.g.:

  • Motor commutation
  • Rotary encoder
  • Motor feedback systems

General information

Sensors in the AL700 family are FixPitch sensors based on the anisotropic magneto resistive (AMR) effect.

These consist of two Wheatstone bridges displaced in relation to each other. As a result, the sensors are adapted to a fixed pole pitch of the measurement scale. When used at a fitting pole pitch, the sensors generate sine and cosine signals at the output. 

All sensors from the AL700 family feature PerfectWave technology and provide extremely low harmonic output signals.

Furthermore, the PurePitch sensor design is predominantly implemented within the AL700 sensor family. The sensors therefore form an average value of the magnetic signals across several poles, without delay or external calculation. This increases the accuracy of the sensor signals as individual errors in measurement scale have less of an impact.

The sensors are available in various processing forms. The sensors are available as bare die for direct assembly using chip on board technology. For SMD assembly on a PCB edge, Sensitec offers sensors in the special SIL6 and LGA6 package.

The LGA6 package provides the benefit that all sensors have identical pinning. It is therefore possible to use different sensors with the same basic layout.

Product variants

NameHousingAmplitudeOffsetAccuracyBridge resistor
AL795Chip, SIL6, LGS6L11 mV/V±0.5 mV/V3 µm4.6 kΩ
AL798Chip, SIL6, LGA6S11.5 mV/V±2 mV/V7 µm3.6 kΩ
AL796Chip, SIL6, LGS6L11 mV/V±2 mV/V5 µm3.4 kΩ
AL797Chip, SIL6, LGS6L11 mV/V±1 mV/V15 µm5.4 kΩ
AL794Chip, SIL6, LGS6L11 mV/V±2 mV/V25 µm62.0 kΩ
AL780Chip, SIL6, LGS6L11 mV/V±1 mV/V25 µm3.2 kΩ

AL780

The AL780 FixPitch sensor is available as a component for chip on board processing in the industrial sector. The sensor is also available as a component suitable for SMD assembly in the SIL6 or in the compact LGA6L.

The sensor layout is adapted to a magnetic pole pitch of 5.0 mm (10 mm pole pair). Because of the large pole pitch, this sensor is not implemented in the PurePitch design.  

You can also order this product via RS Components.

AL794

The AL794 FixPitch sensor is available as a component for chip on board processing in the industrial sector. The sensor is also available as a component suitable for SMD assembly in the SIL6 or in the compact LGA6L.

The sensor layout is adjusted to a magnetic pole pitch of 2.5 mm (5 mm pole pair). The PurePitch design has been realized across 2 poles. This means that this sensor averages the magnetic position information across 2 poles. Single errors on the measurement scale are largely suppressed.

As a high-resistance sensor, the AL794 EcoSensing sensor is ideal for low power applications or battery operation.

AL795

The AL795 FixPitch sensor is available as a component for chip on board processing in the industrial sector. The sensor is also available as a component suitable for SMD assembly in the SIL6 or in the compact LGA6L.

The sensor layout is adapted to a magnetic pole pitch of 0.5 mm (1 mm pole pair). The PurePitch design has been realized across 8 poles. This means that this sensor averages the magnetic position information across 8 poles. This ensures outstanding suppression of single errors on the measurement scale.

You can also order this product via RS Components.

AL796

The AL796 FixPitch sensor is available as a component for chip on board processing in the industrial sector. The sensor is also available as a component suitable for SMD assembly in the SIL6 or in the compact LGA6L.

The sensor layout is adapted to a magnetic pole pitch of 2.0 mm (4 mm pole pair). The PurePitch design has been realized across 2 poles. This means that this sensor averages the magnetic position information across 2 poles. Single errors on the measurement scale are largely suppressed.

You can also order this product from RS Components.

AL797

The AL797 FixPitch sensor is available as a component for chip on board processing in the industrial sector. The sensor is also available as a component suitable for SMD assembly in the SIL6 or in the compact LGA6L.

The sensor layout is adjusted to a magnetic pole pitch of 2.5 mm (5 mm pole pair). The PurePitch design has been realized across 2 poles. This means that this sensor averages the magnetic position information across 2 poles. Single errors on the measurement scale are largely suppressed.

You can also order this product via RS Components.

AL798

The AL798 FixPitch sensor is available as a component for chip on board processing in the industrial sector. The sensor is also available as a component suitable for SMD assembly in the SIL6 or in the compact LGA6S.

The sensor layout is adapted to a magnetic pole pitch of 1.0 mm (2 mm pole pair). The PurePitch design has been realized across 2 poles. This means that this sensor averages the magnetic position information across 2 poles. Single errors on the measurement scale are largely suppressed.

You can also order this product via RS Components.


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Data sheets

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Handling instructions

  • Housing LGA6

    Handling instructions for the LGA6x housing for FixPitch and FreePitch sensors

CAD drawing

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Design features

Sensitec is increasing the sensor efficiency by means of various design modifications to the chip layout.  The patented solutions, described more closely below, also contribute to better signal quality, reduced sensitivity to stray fields and increased control accuracy. 

FixPitch

FixPitch sensors are adjusted to the pole lengths of the measurement scale, i.e. MR strips are geometrically coordinated to a specific pole length. The sine and cosine signals are generated by distributing the Wheatstone bridge resistors along the single pole. This geometric arrangement contributes to the suppression of the harmonics and a reduction in the sensitivity to stray fields. This optimizes the linearity of the sensor.  

PurePitch

The PurePitch design is an extension of the FixPitch concept in which the MR resistors are distributed across several poles. This has an averaging effect on errors in the measurement scale without any signal delay. Because the sensor averages over north and south-poles this principle also serves to suppress the influence of homogenous stray fields better. These improvements are reflected in a higher performance in control systems where these sensors are implemented.

PerfectWave

The PerfectWave design is applied in order to optimize the signal quality of the FreePitch sensors. The MR strips that serve as resistors have a curved form which is used to filter the harmonics when mapping the magnetic field direction in an electric signal. This filtering is implemented using the special geometry and arrangement of the MR strips and does not cause any additional signal propagation delay. The PerfectWave design is particularly effective for small magnetic fields and results in improved linearity, higher accuracy and better signal quality.