This is a dedicated chip designed to provide the hardware required to use the associated sensors in field nulling systems, such as removing the effect of interfering external magnetic fields on sensitive equipment. 

It has been used successfully, for example in dramatically improving the performance of color VDUs in difficult environments. In this context is works in conjunction with external field nulling coils around the sensitive area.

In conjunction with the internal over wound coils in the sensors the ASIC can also be used to make gauss meters with high linearity and switched ranges. 

Package: 18 pin dual-in-line.

Gauss Meter Application Note

This chip provides the hardware to make, with a few external components, a vehicle detector for both fixed and portable use. It can be used, for example, in vehicle detection and census projects, traffic management, car park occupancy sensing and vehicle theft alarm systems.

Equally, at closer ranges with smaller ferrous metal objects, it can be used for conveyor belt counting or proximity detection.

Use of this ASIC requires the FGM-3 sensor to provided the detection input.

Package: 18 pin dual-in-line.

Vehicle Detector Application Note

This ASIC provides the complex hardware needed to make a self calibrating 1-degree of precision, 2-degree of accuracy bolt down orientation compass suitable for platforms or aerials.

The ASIC has a RS232 output with a serial output for direct digital display. 

It compensates for the surrounding magnetic material and for tilt errors in the bolt down mode. If suitably gimballed it could be used for applications other than the bolt-down type. 

This ASIC requires a FGM-2 sensor and has been programmed with the algorithms described in the application note titled "Auto-calibration algorithms for FGM type sensors". It has also an externally programmable, orthogonal adjustment feature to permit correction for the small amount by which the individual sensors might not be truly at right angles to one another.  These two features, used properly, will usually achieve a one degree accuracy though the manufacturer only claims a two degree accuracy with this product.

The full application note should be referred to for complete details and features. SCL-004 Application Note 

Package: 18 pin dual-in-line.

This ASIC provides the ability to make, with a few external components, a highly sensitive earth field magnetometer for both fixed or portable use. It integrates the variations in the earth field over approximately 8 second intervals and gives an extremely sensitive response to tiny variations.

Of particular interest to radio amateurs and amateur astronomers in solar flare and propagation studies, it can also be used in laboratory type magnetometer configurations for ferrous metal measurements and contamination detection techniques.

Package: 18 pin dual-in-line.

Single Axis Earth Field Magnetometer Application Note

Along with 2 FGM type sensors and some external components, this ASIC will allow you to make a gradiometer for detection of local field gradients or anomalies caused by buried ferrous objects or larger scale changes in rock formations. 

Used in the most sensitive configuration and with the appropriate calibration techniques, it may be of interest to archeologists or mineral surveyors. 

At a lower level it can be used in beach-combing, mine detection, finding the "pig in the pipe", cable current detection, and remote shaft rotation sensing.

Package: 18 pin dual-in-line.

Gradiometer Application Note

For use with the SCL-001, SCL-006B and SCL-007 ASICs, if an analog output is needed.

The AD557 is an Analog Devices 8 bit D/A converter in a 16 pin DIP package. It requires only a single +5 volt supply at approximately 15mA and the IC has its own internal precision voltage reference.

The analog output is zero to 2.56 volts at full scale and is capable of driving loads of 1k ohms or greater