what is dac

What is a Digital-to-analog converter

A digital to analog (D/A) converter is a device that generates an analog voltage signal in response to its digital representation. Modern electronic devices often utilize signals or processing of signals in a digital format because digital signals or digital signal processing may have numerous advantages over working with or utilizing signals that are in the analog domain. For example, communication devices often receive an analog voice signal from a microphone, and convert this signal to a digital format for processing. Digital to analog converters are an essential interface circuit from the digital domain into the analog domain and, particularly, the analog signal processing domain. Digital to analog converters are widely used in mixed-mode systems requiring monotonicity where the converter acts as an interface between the digital signal processing and analog signal processing components of such systems. Digital to analog converters are also a key to many analog to digital converter techniques. A DAC takes the binary bits of a digital input signal, which originate from a computer or other type of discrete circuitry, and converts the digital input signal into an analog output voltage that can be used to drive analog devices. D/A converters are designed to convert an N-bit digital value into a corresponding analog signal level. The number (N) of bits forming the N-bit digital value may be as low as two, but 6- and 8-bit D/A converters are ubiquitous, and 16-bit D/A converters are not uncommon. A D/A converter for converting discrete digital data into continuous analog signals can be a converter of ladder resistance network type, segment type, integral type, etc. A D/A converter is typically composed of several DAC elements, which receive digital input data and generate element signals according to the digital input data. The element signal can be voltage type or current type. A signal integrator (or a summing node) adds the element signals outputted from the DAC elements and generates an analog output signal. A DAC can be implemented with an array of weighted analog components that are controlled by an incoming digital code. The outputs of the weighted analog components are then summed and filtered to reproduce a continuous-time signal.


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