UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.
The TLV40x1 comparators have two inputs: one external input (IN) and one internal input that is connected to the integrated voltage reference. The comparator rising threshold is trimmed to the reference voltage (VIT+) while the falling threshold is trimmed to (VIT-). Since the rising and falling thresholds are both trimmed and warranted in the Electrical Characteristics Table, the TLV40x1 is equally suited for undervoltage and overvoltage detection. The difference between (VIT+) and (VIT-) is referred to as the comparator hysteresis and is 20 mV for TLV40x1Ry and 54 mV for TLV4021S5. The integrated hysteresis makes the TLV40x1 less sensitive to supply-rail noise and provides stable operation in noisy environments without having to add external positive feedback to create hysteresis.
The comparator input (IN) is able to swing 5.5 V above (V-) regardless of the device supply voltage. This includes the instance when no supply voltage is applied to the comparator (VS = 0 V). As a result, the TLV40x1 is referred to as fault tolerant, meaning it maintains the same high input impedance when VS is unpowered or ramping up. While not required in most cases, in order to reduce sensitivity to transients and layout parasitics for extremely noisy applications, place a 1 nF to 100 nF bypass capacitor at the comparator input.
For the TLV40x1Ry comparators, the input bias current is typically 10 pA for input voltages between (V-) and (V+) and the value typically doubles for every 10°C temperature increase. The comparator input is protected from voltages below (V-) by an internal diode connected to (V-). As the input voltage goes below (V-), the protection diode becomes forward biased and begins to conduct causing the input bias current to increase exponentially. A series resistor is recommended to limit the input current when sources have signal content that is less than (V-).
For the TLV4021S5, the input bias current is limited by the internal resistor divider with typical impedance of 2M ohms.