The DAC package contains digital to analogue converters (DACs). These components can be used to convert a digital signal, such as one that has been processed in a microprocessor application, to be converted into an analogue one.
This conversion may be useful for a signal which has been artificially generated, or processed in a digital context, and subsequently needs to be transmitted over some physical analogue medium - for example over a telephone line, or played over a loudspeaker.