The ILD74, ILQ74 is an optically coupled pair with a GaAIAs infrared LED and a silicon NPN phototransistor. Signal information, including a DC level, can be transmitted by the device while maintaining a high degree of electrical isolation between input and output. The ILD74, ILQ74 is especially for driving medium-speed logic, where it may be used to eliminate troublesome ground loop and noise problems. Also it can be used to replace relays and transformers in many digital interface applications, as well as analog applications such as CTR modulation

The ILD621/ILQ621 and ILD621GB/ILQ621GB are multi-channel phototransistor optocouplers that use GaAs IRLED emitters and high gain NPN silicon phototransistors. These devices are constructed using double molded insulation technology. This assembly process offers a withstand test voltage of 7500 VDC. The ILD621/ILQ621GB is well suited for CMOS interfacing given the CTRCEsat of 30 % minimum at IF of 1.0 mA. High gain linear operation is guaranteed by a minimum CTRCE of 100 % at 5.0 mA. The ILD/Q621 has a guaranteed CTRCE 50 % minimum at 5.0 mA. The transparent ion shield insures stable DC gain in applications such as power supply feedback circuits, where constant DC VIO voltages are present.