ZHCS840G February 2012 – February 2019 TPS3700
The TPS3700 device is a voltage detector that combines two comparators. Each comparator has one external input (inverting and noninverting); the other input is connected to the internal reference. The comparator rising threshold is designed and trimmed to be equal to the reference voltage (400 mV). Both comparators also have a built-in falling hysteresis that makes the device less sensitive to supply rail noise and ensures stable operation.
The INA+ and INB- inputs can swing from ground to 6.5 V, regardless of the device supply voltage used. Although not required in most cases, good analog design practice is to place a 1-nF to 10-nF bypass capacitor at the comparator input for extremely noisy applications to reduce sensitivity to transients and layout parasitics.
For comparator A, the corresponding output (OUTA) is driven to logic low when the input INA+ voltage drops below (VIT+ – Vhys). When the voltage exceeds VIT+, the output (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 VIT+. When the voltage drops below VIT+ – Vhys the output (OUTB) goes to a high-impedance state; see Figure 1. Together, these comparators form a window-detection function as discussed in the Window Voltage Detector section.