DAC resolution concept: One way to compute resolution is to take the ratio of one LSB step size to the full-scale output range of the digital-to-analog converter.

Introduction / Context:
Resolution quantifies the smallest change a DAC can produce in its output. Expressing resolution as a ratio links the LSB step to full-scale, helping designers relate code width to analog precision in percent or parts per million (ppm).

Given Data / Assumptions:

• n-bit DAC with full-scale range FS (voltage or current).
• One LSB step size = FS / (2^n − 1) or FS / 2^n depending on convention; ratio form remains consistent.
• Reference and scaling networks are ideal for the definition.

Concept / Approach:
Resolution can be stated as a fraction or percentage: LSB_step / FS. For a mid-tread DAC using FS_ref and 2^n codes, the step is approximately FS / 2^n. Thus resolution ≈ 1 / 2^n in normalized units, or 100% / 2^n as a percentage. This complements stating resolution directly as the LSB size in volts or amperes.

Step-by-Step Solution:

Verification / Alternative check:
For n = 8 and FS = 5 V, step ≈ 5 / 256 = 19.53 mV, ratio = 19.53 mV / 5 V ≈ 0.0078125 = 0.78125% = 1 / 128, consistent with 1 / 2^n when using the 0-to-FS idealization.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing resolution with accuracy; mixing FS of the code range with the reference tolerance; ignoring gain/offset errors that do not change resolution.

Final Answer:
Correct