6 Concern With Rise Time Accelerators

Rise time accelerators are included into specialized I²C translators or buffers to help drive heavy capacitive loaded I²C buses. This allows the external pullup resistors to be large to lower voltage output lows (VoLs). If the rise time accelerator circuit is designed to trigger upon only a voltage threshold level, the SDA hand-off delay can accidentally trigger the rise time accelerators to turn on and cause contention between the high-side driver of the rise time accelerator and the I²C device trying to pull the SDA line low. The consequence of this could cause damage to the devices under contention. So for this reason, the SDA lines on an I²C bus should be monitored to see if the SDA handoff delay occurs. If the SDA handoff delay occurs then the I²C system should be thoroughly tested across temperature, loading conditions, and boards whenever devices with rise time accelerators must be included on the bus where handoff delays are seen.