Why does hang-time matter?

Hang time matters because it is inherent to every I2C system that utilizes passFET architecture. Note that hang time delay, although present, is much more harmless to an I2C system than detrimental. PassFET can be found in a variety of integrate circuits ranging from general purpose I2C multiplexers to common level translators. In general, there is little threat to the signal integrity of I2C systems due to hang-time. PassFET structures in I2C applications produce accurate data for I2C communication even up to faster speeds such as fast-mode+ (0 to 1MHz).

Even in the worst-case scenario of this application note, hang time was measured to be 111.85ns. The I2C address 0x74 is sent with the following waveform.

Figure 2-12 Hang Time is Unnoticeable

Hang time in this case presents no threat to the I2C application using the TCA39306. The address 0x74 is still sent properly without data corruption and level translates properly from 1.8V to 3.3V.