This part is a kind of semiconductor called AS5311.

Function of this product has High Resolution Magnetic Linear Encoder.

Manufacturers : ams

Image and pinout :

Some of the text within the PDF file :

AS5311 High Resolution Magnetic Linear Encoder 1 General Description The AS5311 is a contactless high resolution magnetic linear encoder for accurate linear motion and off-axis rotary sensing with a resolution down to <0.5µm. It is a system-on-chip, combining integrated Hall elements, analog front end and digital signal processing on a single chip, packaged in a small 20-pin TSSOP package. A multi-pole magnetic strip or ring with a pole length of 1.0mm is required to sense the rotational or linear motion. The magnetic strip is placed above the IC at a distance of typ. 0.3mm. The absolute measurement provides instant indication of the magnet position within one pole pair with a resolution of 488nm per step (12bit over 2.0mm). This digital data is available as a serial bit stream and as a [ ... ]

AS5311 PDF Datasheet Download