High-Speed Optocoupler

 Optocouplers are popularly perceived as being “slow” and are thus excluded from many designs in which they could potentially serve as excellent solutions to difficult design challenges. These solutions include enhancing noise immunity, protection against EMI emissions, ground-loop control, and safety isolation. At one time, when the only optocoupler options were discrete BJT phototransistors, this reputation for low speed was well earned; however, today's optocouplers can attain switching speeds in the single digit nanosecond range.