The AWM2000 Series microbridge mass airflow sensor is a passive device comprised of two Wheatstone bridges.
The heater control circuit is required for operation per specifications. The sensing bridge supply circuit is also required for operation per specifications. These two circuits are not on board the package and must be supplied in the application. The differential amplifier is a useful interface for the sensing bridge. It can be used to introduce the gain and to introduce voltage offsets to the sensor output