What is an Offset Strap, and what does it do?
The offset strap in Linear Mode magnetic sensors is a spiral of metal located over the magneto-resistive elements of the sensor to form a coil. This spiral coil shaped strap can induce localized magnetic fields upon the sensor when a current is passed through the strap. The purpose of these induced fields are to buck or boost the incident magnetic fields on the sensor. By doing so, these strap induced magnetic fields sum with the external fileds, or “offset” the external fields. Use of the offset strap is often used to extend the linear range of the sensor, or buck stray fields from nearby magnetized metals (e.g. automobile chassis), or become part of an active feedback network that extends the dynamic range of the sensing circuits. Most designers do not use this strap, and it can be left unconnected or connected to ground at only one side.
