Honeywell HMC2003

The Honeywell HMC2003 is a high sensitivity, threeaxis magnetic sensor hybrid assembly used to measure low magnetic field strengths. Honeywell’s most sensitive magneto-resistive sensors (HMC1001 and HMC1002) are utilized to provide the reliability and precision of this magnetometer design. The HMC2003 interface is all analog with critical nodes brought out to the pin interfaces for maximum user flexibility. The internal excitation current source and selected gain and offset resistors, reduces temperature errors plus gain and offset drift. Three precision low-noise instrumentation amplifiers with 1kHz low pass filters provide accurate measurements while rejecting unwanted noise.

Honeywell’s three axis magnetic sensor hybrid uses three permalloy magneto-resistive sensors and custom interface electronics to measure the strength and direction of an incident magnetic field. These sensors are sensitive to magnetic fields along the length, width, and height (X, Y, Z axis) of the 20-pin dual-in-line hybrid. Fields can be detected less than 40 microgauss and up to ±2 gauss. Analog outputs are available for each X, Y and Z axis from the hybrid. With the sensitivity and linearity of this hybrid, changes can be detected in the earth’s magnetic field to provide compass headings or attitude sensing. The high bandwidth of this hybrid allows for anomaly detection of vehicles, planes, and other ferrous objects at high speeds.

The hybrid is packaged on a small printed circuit board (1” by 0.75”) and has an on-chip +2.5 voltage reference that operates from a single 6 to 15V supply. The hybrid is ideal for applications that require two- or three-axis magnetic sensing and have size constraints and need a magnetic transducer (magnetometer) front-end.

Integrated with the sensor elements composed of wheatstone bridge circuits, are magnetically coupled straps that replace the need for external field coils and provide various modes of operation. The Honeywell patented integrated field offset straps (Xoff+ and Xoff-, etc.) can be used electrically to apply local magnetic fields to the bridges to buck, or offset an applied incident field. This technique can be used to cancel unwanted ambient magnetic fields (e.g. hardiron magnetism) or in a closed loop field nulling measurement circuit. The offset straps nominally provide 1 gauss fields along the sensitive axis per 48mA of offset current through each strap.

The HMC2003’s magnetic sensors can be affected by high momentary magnetic fields that may lead to output signal degradation. In order to eliminate this effect, and maximize the signal output, a magnetic switching technique can be applied to the bridge using set/reset pins SR+ and SR-) that eliminates the effect of past magnetic history.

• 20-pin Wide DIP Footprint (1” by 0.75”)
• Precision 3-axis Capability
• Factory Calibrated
• Analog Outputs
• 40 micro-gauss to ±2 gauss Dynamic Range
• Analog Output at 1 Volt/gauss (2.5V @ 0 gauss)
• Onboard +2.5 Volt Reference
• +6 to +15 Volt DC Single Supply Operation
• Very Low Magnetic Material Content
• -40℃ to 85℃ Operating Temperature Range