Optical encoder shrinks further still

The industry's smallest reflective incremental optical encoder comes in a surface-mount package with dimensions of 3.00 x 3.28 x 1.262mm.

Avago Technologies has announced the industry's smallest reflective incremental optical encoder.

It is offered in a surface-mount package with dimensions of 3.00 x 3.28 x 1.262mm.

The Avago AEDR-8400 encoder combines extremely small size with 254 lines per inch resolution, low power consumption and wide operating temperature range.

These attributes make it an excellent choice for consumer, office, industrial and automotive interior applications ranging from scanners, printers, miniature cameras, and seat adjustment and rear view mirror controls in automobiles.

The AEDR 8400 is smaller than the Avago AEDR-83xx optical encoders, which, up to now, were the industry's smallest.

It provides two-channel quadrature output, a count frequency up to 15kHz and -20 to +85C operating temperature range.

The AEDR-8400 is also designed for low power consumption, operating from a single 2.8V (nominal) supply, drawing 12mA (including 6mA LED current), typical.

Its lead-free packaging complies with the European Union's RoHS Directive.

Compared with magnetic encoders, Avago's reflective optical encoders offer higher resolution (magnetic encoders are typically limited to approximately 150 line-per-inch raw resolution).

In motor control applications the magnetic encoder's lower resolution can cause torque ripple that increases motor vibration.

Magnetic sensors also generate magnetic fields, which may call for magnetic shielding to prevent interference with nearby components.

The Avago AEDR-8400 series of reflective encoders consist of an LED light source, a special photodetector IC with integrated electronics, and integrated optics.

They can be used with a reflective code wheel to sense rotary position and velocity, or with a linear code strip to sense linear position and velocity.

The devices provide two-channel digital outputs in quadrature, which provides both count and direction information.

They are insensitive to axial play and maintain performance and accuracy over a wide variation in the gap between sensor and code wheel or strip.

"The AEDR-8400, 254LPI is just the first resolution option in a series of miniature reflective optical encoders under development at Avago Technologies", said Chong Khin Mien, Vice President and General Manager of Avago Technologies' Motion Control Products Division.

"Avago's continuous innovation in developing the industry's smallest form factor encoders with the widest range of resolutions helps us meet our customers' changing needs for various applications and shortens their time to market".

The Avago AEDR-8400 reflective optical encoder is immediately available through Avago Technologies' direct sales channel and worldwide distribution partners.

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