The 6N137 / ICPL2601 optocouplers consist of a GaAsP light emitting diode and a high gain integrated photo detector to provide 2500Volts RMS electrical isolation between input and output. An enable input allows the detector to be strobed. The output of the detector I.C. is an open collector Schottky clamped transistor. The ICPL2601 has an internal shield which provides a guaranteed common mode transient immunity specification of 1000V/s minimum.This unique design provides maximum ac and dc circuit isolation while achieving TTL compatibility. The coupled parameters are guaranteed over the temperature range of 0C to 70C, such that a maximum input signal of 5mA will provide a minimum output sink current of 13mA(equivalent to fan-out of eight gates)