AL700 family AMR FixPitch sensors for angle and length measurement
General information
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
Product variants
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
Design features
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.
Application examples
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
| Name | Housing | Amplitude | Offset | Accuracy | Bridge resistor |
|---|---|---|---|---|---|
| AL795 | Chip, SIL6, LGS6L | 11 mV/V | ±0.5 mV/V | 3 µm | 4.6 kΩ |
| AL798 | Chip, SIL6, LGA6S | 11.5 mV/V | ±2 mV/V | 7 µm | 3.6 kΩ |
| AL796 | Chip, SIL6, LGS6L | 11 mV/V | ±2 mV/V | 5 µm | 3.4 kΩ |
| AL797 | Chip, SIL6, LGS6L | 11 mV/V | ±1 mV/V | 15 µm | 5.4 kΩ |
| AL794 | Chip, SIL6, LGS6L | 11 mV/V | ±2 mV/V | 25 µm | 62.0 kΩ |
| AL780 | Chip, SIL6, LGS6L | 11 mV/V | ±1 mV/V | 25 µm | 3.2 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.
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.
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.
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.
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.
Handling instructions
- Housing LGA6
Handling instructions for the LGA6x housing for FixPitch and FreePitch sensors
CAD drawing
- AL700 familiy
3D-PDF
Your contact person
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.