7.3.1 Inputs (INA, INB)

The TPS3701 combines two comparators with a precision reference voltage. Each comparator has one external input; the other input is connected to the internal reference. The rising threshold on INB and the falling threshold on INA are designed and trimmed to be equal to the reference voltage (400 mV). This configuration optimizes the device accuracy when used as a window voltage detector. Both comparators also have built-in hysteresis that proves immunity to noise and ensures stable operation.

The INA and INB inputs swings from ground to 1.7 V (7.0 V absolute maximum), regardless of the device supply voltage used. Although not required in most cases, it is good analog design practice to place a 1-nF to 10-nF bypass capacitor at the comparator input for noisy applications in order to reduce sensitivity to transient voltage changes on the monitored signal.

For comparator A, the corresponding output (OUTA) is driven to logic low when the input INA voltage drops below V_IT–(INA). When the voltage exceeds V_IT+(INA), OUTA goes to a high-impedance state; see Figure 1.

For comparator B, the corresponding output (OUTB) is driven to logic low when the voltage at input INB exceeds V_IT+(INB). When the voltage drops below V_IT–(INB) OUTB goes to a high-impedance state; see Figure 1. Together, these two comparators form a window voltage detector function as described in the Window Voltage Detector Considerations section.