MAX987EXK+T

The MAX987EXK+T is a low-cost comparator with a wide range of applications. It has an open-collector output which greatly enhances its flexibility, while the low-input-current attribute ensures minimal current consumption. Additionally, the hysteresis function provides noise immunity and allows the comparator to respond to minor changes in input voltage. It has a guaranteed 10 μs response time and an extended temperature range of -30°C to +85°C.

This device consists of two parts: the main operational amplifier and the hysteresis loop. The operational amplifier consists of two differential inputs, two voltage reference inputs, an inverting input node, an output terminal and a protection diode. When a signal is applied to the non-inverting input, it is amplified by the operational amplifier and sent to the output terminal. The PVREF voltage reference is the reference for the output signal and the NVREF voltage is the reference for the hysteresis loop. Anode and cathode diodes are also incorporated in the device at the output terminal to protect against accidental reverse voltage.

The device can be used to compare two voltage signals by applying different voltages on the two differential inputs. Whenever the input voltage at the non-inverting input exceeds the reference voltage, the output voltage is high. If the input voltage at the non-inverting input is less than the reference voltage, the output voltage is low. This action continues as long as the input stays within the given range. The hysteresis loop ensures that this condition persists until the input voltage changes. The input voltage must exceed the voltage at which the output changed its state in the first place before the next output change will occur.

In addition to comparing two voltage signals, the device can also be used to monitor changing signals, for example to initiate a process whenever the signal exceeds or goes below a given threshold. It can be used as a power-on reset circuit, a level detect circuit, or a voltage monitor circuit.