Linear encoder provides submicron resolution

This integrated linear Hall encoder can be used as an alternative to optical encoders.

For linear motion sensing, a multi-pole magnetic strip is used and for rotary motion sensing the magnetic strip is replaced by a multi-pole magnetic ring.

For applications such as this, an incremental output with a resolution of 10-bit per pole pair and a travelling speed up to 650mm per second is available.

Using, for example, a multi-pole magnetic ring with a diameter of 41.7mm, a resolution of 16 bit (65.536 steps per revolution) can be achieved.

In conjunction with a 2mm pole-pair magnetic strip, the AS5311 provides a 1.95um resolution signal at its incremental output and a 488nm resolution signal at its serial output.

'The AS5311 together with the magnetic strip are the only two components required to build a robust submicron-resolution position feedback system,' said Josef Janisch, encoder product manager at Austriamicrosystems.

'This small form factor allows AS5311 to be integrated in autofocus, zoom and vibration reduction systems in cameras, switching systems in fibre optics or other micro-positioning applications where tight space is a concern and high resolution is demanded,' he added.

Austriamicrosystems' encoder chip also provides extended diagnostic features that constantly monitor the placement of the magnet above the device.

These features allow early detection of mechanical systems failures.

In addition, the device compensates for the adverse effects of unwanted external magnetic fields.

The AS5311 can be operated with either 3.3V or 5V supply voltage and is available in a 20-lead TSSOP-package.

The device is specified for an ambient temperature range from -40 to +125C.