The SENSE input can vary from 0V to 6.0V, regardless of the device supply voltage used. The SENSE pin is used to monitor a critical voltage rail or push-button input. If the voltage on this pin drops below V_IT-, then RESET/RESET is asserted after the sense delay time set by CTS. When the voltage on the SENSE pin rises above the positive threshold voltage V_IT- + V_HYS, RESET/RESET deasserts after the reset delay time set by CTR. The internal comparator has built-in hysteresis to make sure well-defined RESET/RESET assertions and deassertions even when there are small changes on the voltage rail being monitored.

The TPS3899-Q1 device is relatively immune to short transients on the SENSE pin. Glitch immunity
(t_{GI_VIT-SENSE}), found in Section 6.6, is dependent on threshold overdrive, as illustrated in Figure 6-7. Although not required in most cases, for noisy applications, good analog design practice is to place a 10nF to 100nF bypass capacitor at the SENSE input to reduce sensitivity to transient voltages on the monitored signal.