The gallium aluminum arsenide feature provides a higher radiated output than gallium arsenide at the same forward current. Each OP231, OP232, OP233, OP234 and OP235 device is lensed to provide a narrow beam angle (18°) between half power points. The 890 nm wavelength closely matches the spectral response of silicon phototransistors, while the narrow beam angle – combined with the specified radiant intensity of the OP231 series – facilitates easy design in beam interrupt applicaƟons in conjuncƟon with the OP800 or OP598 series photosensors. The OP231 series is mechanically and spectrally matched to OP800, OP593 and OP598 phototransistors.