The TMP4718 T_CRIT pin is an active-low, open-drain output which is asserted at the end of a conversion cycle when the measured temperature exceeds a T_CRIT Limit defined in the T_CRIT limit registers. The T_CRIT pin deasserts at the end of a conversion cycle if the temperature measurement is less than the T_CRIT limit – T_CRIT Hysteresis. The T_CRIT Hysteresis is set in the T_CRIT Hysteresis register. A T_CRIT Status register flag is set at the end of a conversion cycle when the measured temperature exceeds a T_CRIT Limit. When the TMP4718 is set in interrupt mode, the status register flag is cleared by reading the status register. Reading the status register will set the ALERT mask bit of the Configuration Register. The ALERT mask bit does not mask the T_CRIT pin. The status register flag will continue to set after the end of a conversion cycle until the temperature measurement is below the T_CRIT limit – T_CRIT Hysteresis value or the device is reset. There are separate T_CRIT Limit values and status register flags for the remote and local temperature measurements.

Figure 8-7 shows the behavior of the T_CRIT pin and flags in interrupt mode.

Figure 8-7 T_CRIT Output Timing Diagram-Interrupt Mode

When the TMP4718 is in comparator the status register flag is only cleared at the end of a conversion cycle if temperature measurement is below the T_CRIT limit – T_CRIT Hysteresis value. The ALERT mask bit does not set after reading the status register in comparator mode. Figure 8-8 shows the behavior of the T_CRIT pin and flags in comparator mode.

Figure 8-8 T_CRIT Output Timing Diagram-Comparator Mode