There are many binary coding schemes in existence. The single coding method nearly always used for DACs is Straight Binary, although other input codes are sometimes used.
We have said that the DAC is a multiplier because the output is proportional to the product of the input word and the DAC reference. Other terms that affect the DAC output are the DAC gain, G, and resolution, n.
- The Input/Output transfer function is given by the formula indicated here. You may sometimes see this formula without the "G" (Gain) term. This is because the gain of most DACs is "1". This formula is a direct result of the fact that the DAC multiplies the digital input word and its analog reference to produces an output level.
- Where G = DAC Gain Factor
D = Digital Input Word Decimal Value
n = DAC Resolution (# of Output Bits)
VREF (or IREF ) = DAC Reference Voltage (or Current)
It's True! The normal ½ LSB offset that is built into ADCs is not incorporated into DACs.
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