The VTHR is spec is part of it, we also need to look at the SRTHRESH spec. It needs to see the line voltage rising at a certain slew rate while crossing the threshold to turn on the boost current.
The LTC4311 idles when the bus is high. Its well suited for battery powered applications because weaker pull-ups can be used while still maintaining data rates.
And it won't be in contention with any of the devices on the I2C bus trying to pull down. Its only active for positive bus transitions.
Thank you for your quick response.I almost understand it.(The following is an extreme example)If the low voltage is stable at 1V, is it correct to recognize that the LTC4311 is idle because it exceeds VTHR but not SRTHRESH?
Correct. The LTC4331 only reacts to rising edges on the bus. Its idling with DC conditions.
Thank you very much.I was convinced.