i) Easier to build accurately as only two precious metal film resistors are required.
ii) Number of bits can be expanded by adding many sections of same R/2R value
iii) Due to the small resistance spread only 2: the R-2R ladder can be fabricated monolattical with high accuracy and stability
Sources of Errors in DAC:
There are mainly three errors in DAC :
i) Lineraity Error:-
The error is defined as the amount by which the actual o/p differs from the ideal straight line o/p.
It is mainly due to the errors in the current source resistor values.
ii) Offset Error:-
The offset error is defined as the non zero level of the o/p voltgae when all inputs are zero. It adds a constant value to all o/p values. It is due to the presence of offset voltage in op-amp and leakage currents in the current switches.
iii) Gain Error:-
It is defined as the difference between the calculated gain of the current to voltage converter and the actual gain achieved. It is due to the errors in the feed back resistor in the current to voltage converter of op-amp.