Method provides fast, glitch-free isolation of I_2C and SMBus signals

摘要

I_2C is a popular serial protocol for power controllers, ADCs and DACs, EEPROMs, and other devices. In certain data-acquisition and power-control situations, you must isolate the I_2C master from one or more slave devices for noise, grounding, or safety issues. Also, although 128 peripherals may connect to the bus, at some point, differences in ground potential and excessive bus capacitance begin to erode noise and timing margins. This Design Idea shows how to provide fast, glitch-free optical isolation of I_2C or SMBus signals by using a method that meets the requirements for the 400kHz enhanced-PC-bus specification.