The PS9587, PS9587L1, PS9587L2 and PS9587L3 are optically coupled isolators containing a GaAlAs LED on the input side and a photo diode and a signal processing circuit on the output side on one chip. The PS9587L1 and PS9587L2 are designed specifically for long creepage-distance as well as high common mode transient immunity (CMR) and high speed digital output type. Consequently, they are suitable for high speed logic interface that needs long creepage-distance (8 mm) on mounting. The PS9587L1 is lead bending type for long creepage distance. The PS9587L2 is lead bending type for long creepage distance (Gull-wing) for surface mount. The PS9587L3 is lead bending type (Gull-wing) for surface mounting.