Q. Explain working of Digital-to-Analog Converters?

Digital-to-Analog (D/A) Converters

For the results of digital computations to be used in the analog world, it becomes necessary to convert the digital values to proportional analog values. Figure shows the block diagram of a typical digital-to-analog (D/A) converter, which accepts an n-bit parallel digital code as input and provides an analog current or voltage as output. For an ideal D/A converter, the analog output for an n-bit binary code is given by

V₀ analog output voltage
V_ref reference analog input voltage
b₀ most significant bit of binary input code
b_n-1 least significant bit of binary input code

In order to provide current-to-voltage conversion and/or buffering, an op amp is used at the output. However, in some high-speed applications where a limited output voltage range is acceptable, a resistor, instead of an op amp, is used for the current-to-voltage conversion, thereby eliminating the delay associated with the op amp.