Digital-to-Analog Converters (DACs): The practical issues with a binary-weighted resistor DAC (large resistor ratio spread, switch accuracy, and sensitivity to tolerances) can be overcome by using which alternative architecture?

Introduction / Context:
Digital-to-analog converters transform binary input words into proportional analog voltages or currents. A common entry-level topology is the binary-weighted resistor DAC, but it suffers from component-ratio and switching challenges as resolution grows. This question asks which DAC architecture addresses those pain points most directly.

Given Data / Assumptions:

• Target: overcome problems of binary-weighted resistor DACs.
• Typical problems include wide resistor value spread (1R, 2R, 4R, …), tight tolerance needs, and switch on-resistance errors.
• We assume mainstream voltage-output DAC implementations.

Concept / Approach:
The R/2R ladder DAC replaces the exponential resistor set with only two resistor values: R and 2R. This uniformity improves matching, reduces sensitivity to absolute tolerance (relying more on ratio matching), and eases layout. It also simplifies switch drive because each bit sees the same impedance environment.

Step-by-Step Solution:

Verification / Alternative check:
Compare INL/DNL sensitivity: for the same process, R/2R ladders exhibit better monotonicity and yield because they depend on resistor ratio matching rather than absolute value precision.

Why Other Options Are Wrong:
an 8-bit binary-weighted resistor DAC: retains the same structural issues; it merely fixes resolution at 8 bits.

a staircase DAC: vague term, generally refers to the DAC output, not a topology that solves matching.

a flash DAC: very fast ADC type; not a DAC architecture that addresses resistor weighting problems.

Common Pitfalls:
Assuming “more bits” or “different code” removes mismatch problems; architecture, not just resolution, determines sensitivity.

Final Answer:
an R/2R ladder DAC