NVE's AA and AB Series analog GMR sensors offer unique and unparalleled magnetic sensing capabilities. These sensors are characterized by high sensitivity to applied magnetic fields, excellent temperature stability, low power consumption, and small size. These characteristics make them suitable for use in a wide variety of applications, from rugged industrial and automotive position, speed, and current sensors, to low voltage, battery-powered sensors for use in hand-held instrumentation and implantable medical devices. The unmatched versatility of these basic magnetic sensors makes them an excellent choice for a wide range of analog sensing applications. The AA series sensors use NVE's patented GMR materials and on-chip flux concentrators to provide a directionally sensitive output signal. These sensors are sensitive in one direction in the plane of the IC, with a cosine-scaled falloff in sensitivity as the sensor is rotated away from the sensitive direction. Also, these devices provide the same output for magnetic fields in the positive or negative direction along the axis of sensitivity (omnipolar output). All sensors are designed in a Wheatstone bridge configuration to provide temperature compensation. Two packages are offered, an SOIC8 and an MSOP8. These sensors are also available in die form on a special order basis. Three families of NVE's basic AA series sensors are offered: the standard AA series, the AAH series, and the AAL series. Each of these sensor families uses a different GMR material, with its own characteristics. The comparison table below summarizes the different characteristics of the GMR materials: AA Series High Medium High AAH Series Very High Low High Very High AAL Series High Medium Low Very High
Sensitivity to Applied Fields Field Range of Operation Hysteresis Temperature Range
The AB series sensors are differential sensor devices, or gradiometers, which take advantage of the high output characteristics of NVE's GMR materials. Two families of AB sensors are offered: the standard AB series, and the ABH series. They have operational characteristics similar to the AA and AAH sensors described in the table above, but with the bipolar linear output characteristics of a differential sensor. Within these different sensor families, customers can find an excellent match to their analog sensor requirements.
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For comparison and product selection purposes, the following table lists all available AA and AB series analog sensors, with some of their key characteristics:
Part Number Linear Range (|Oe1|) Min Max Resistor Spacing (mm) Maximum Nonlinearity Uni.2) Maximum Hysteresis Uni.2) Maximum Operating Temp (°C) Typical Resistance (Ohms) 2.5K 1.2K Package
1 Oersted (Oe) = 1 Gauss in air. Unipolar operation means exposure to magnetic fields of one polarity, for example to +30 Gauss, to 50 Gauss. Bipolar operation (for example + 10 Gauss) will increase nonlinearity and hysteresis.
Excellent Sensitivity to Applied Magnetic Fields Wheatstone Bridge Analog Output Operating Temperature to 125°C Continuous Wide Linear Range of Operation Near-Zero Voltage Operation to >1MHz Frequency Response Small, Low Profile Surface Mount Packages General Motion, Speed, and Position Sensing Low Power, Low Voltage Applications Low Field Sensing for Magnetic Media Detection Current Sensing
The basic AA series GMR sensors are general purpose magnetometers for use in a wide variety of applications. They exhibit excellent linearity, a large output signal with applied magnetic fields, stable and linear temperature characteristics, and a purely ratiometric output.