The ILD/Q621 and ILD/Q621GB are multi-channel phototransistor optocouplers that use GaAs IRLED emitters and high gain NPN silicon phototransistors. These devices are constructed using over/under leadframe optical coupling and double molded insulation technology. This assembly process offers a withstand test voltage of 7500 VDC. The ILD/Q621GB is well suited for CMOS interfacing given the CTRCEsat of 30% minimum at IF of 1 mA. High gain linear operation is guaranteed by a minimum CTRCE of 100% at 5 mA. The ILD/Q621 has a guaranteed CTRCE of 50% minimum at 5 mA. The TRansparent IOn Shield insures stable DC gain in applications such as power supply feedback circuits, where constant DC VIO voltages are present.