8.2.1.1 Design Requirements

The basic usage of a comparator is to indicate when a specific analog signal has exceeded some predefined threshold. In this application, the negative input (IN–) is tied to a reference voltage, and the positive input (IN+) is connected to the input signal. The output is pulled up with a resistor to the logic supply voltage, V+ with a pullup resistor.

For an example application, the supply voltage is 5V. The input signal varies between 1 V and 3 V, and we want to know when the input exceeds 2.5 V±1%. The supply current draw should not exceed 1 mA.