Edited by Stephen J. Mraz
The market’s smallest three-channel reflective encoder, the new line of AEDR-850× encoders from Avago, San Jose, feature an LED light source, photodetecting and interpolator circuitry, and three channels in a 3.95 × 3.40-mm leadless package. The 1×, 2×, and 4× interpolation circuitry, together with encoding resolutions of 304 lines/in. (12 lines/mm), gives users design flexibility. The optical- based encoders are significantly less susceptible to EMI compared with Hall-effect devices.
The chips operate from a single 5-V power supply and can handle temperatures from –20 to 85°C. The encoders are also TTL compatible, letting outputs interface directly with most signal-processing circuitries.
The AEDR-8500 reflective encoder is gated 90°, the AEDR-8501 encoder is gated 180°, and the AEDR-8502 encoder is ungated 360°. They are priced at $6.75 each in 100-piece lots.