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A DAC Performs: Voltage-to-Frequency, Digital-to-Analog, Current-to-Resistance, or Analog-to-Digital?

A DAC Performs: Voltage-to-Frequency, Digital-to-Analog, Current-to-Resistance, or Analog-to-Digital?

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Nov 1, 2026

A DAC performs (ii) Digital-to-analog conversion—it maps an nn-bit digital input code to an analog output (voltage and/or current) proportional to that code (within resolution and accuracy limits).3

This is the direct “reverse” of an ADC which performs (iv) Analog-to-digital conversion.2

A voltage-to-frequency converter is instead a different functional block type (often called VFC), and it performs neither DAC nor ADC conversion; it generates a pulse frequency proportional to input voltage. Likewise, “current-to-resistance conversion” describes other analog relationships (e.g., measuring or controlling RR via II), not the canonical DAC function; a DAC is specifically a digital-code-to-analog-signal converter.2

Quick elimination of the options

Footnotes

  1. Digital-to-Analog Converter - an overview - Defines DAC as transforming numeric codes into an analog signal. ↩ ↩2

  2. Digital to Analog Converter (DAC) - Types, Working & Applications - States DAC converts digital signals into analog voltage or current. ↩ ↩2

  3. Getting Started with Digital-to-Analog Converter (DAC) - Explains DAC converts a register value into an analog voltage within a reference range. ↩

  4. Analog-to-digital converter - Wikipedia - Describes ADC converting continuous analog to discrete digital; includes sampling and quantization. ↩

  5. What Is an Analog-to-Digital Converter (ADC)? - Defines ADC as converting continuous analog signals into discrete digital numbers. ↩

  6. Voltage-to-Frequency Converters: How They Work and Where They’re Used - Explains VFC principle: integrator + threshold switching yields output frequency proportional to input voltage. ↩

How a DAC maps a digital code to an analog output

  1. 1
    Step 1

    A binary word (e.g., nn bits) is presented to the DAC inputs.

  2. 2
    Step 2

    Internally, the DAC uses a circuit (e.g., resistor ladder / summing amplifier) to combine the bits into a single analog value; in many DAC types, the output is proportional to the code.

    Footnotes

    1. Digital to Analog Converter (DAC) - Types, Working & Applications - States DAC converts digital signals into analog voltage or current. ↩

  3. 3
    Step 3

    The DAC outputs a voltage and/or current whose level corresponds to the numeric value of the digital code, typically within the range set by reference voltage/current.2

    Footnotes

    1. Digital-to-Analog Converter - an overview - Defines DAC as transforming numeric codes into an analog signal. ↩

    2. Getting Started with Digital-to-Analog Converter (DAC) - Explains DAC converts a register value into an analog voltage within a reference range. ↩

  4. 4
    Step 4

    For an nn-bit DAC, ideal step size scales like 1/2n1/2^n of the full-scale range, so higher resolution yields finer analog steps.2

    Footnotes

    1. Digital-to-Analog Converter - an overview - Defines DAC as transforming numeric codes into an analog signal. ↩

    2. Digital to Analog Converter (DAC) - Types, Working & Applications - Provides step size relation textRange/2n\\text{Range}/2^n and discusses resolution. ↩

Why the correct choice is (ii): Digital-to-analog conversion

A DAC converts numeric codes into an analog signal (voltage or current). This is explicitly stated in common DAC references: “transforms a series of numeric codes into an analog signal” and “converts a digital signal into an analog signal (voltage or current).”2

A typical hardware realization uses either:

  • Binary-weighted DAC (conceptually simple but requires precise resistors), or
  • R-2R ladder DAC with a summing amplifier to produce the analog output from the digital bits.

Either way, the function remains: digital code → analog output.2

Footnotes

  1. Digital-to-Analog Converter - an overview - Defines DAC as transforming numeric codes into an analog signal. ↩

  2. What Is a DAC? Digital-to-Analog Conversion Demystified - Describes DAC converting digital data (binary code) to an analog signal. ↩

  3. R-2R DAC (R-2R Digital-to-Analogue Converter) - Explains R-2R ladder DAC and that it converts digital voltage signals to an analog output via a summing amplifier. ↩ ↩2

  4. Digital to Analog Converter (DAC) - Types, Working & Applications - States DAC converts digital signals into analog voltage or current. ↩

Key contrast: DAC vs ADC

A DAC outputs analog from digital, while an ADC outputs digital from analog.2

Footnotes

  1. Digital-to-Analog Converter - an overview - Defines DAC as transforming numeric codes into an analog signal. ↩

  2. Analog-to-digital converter - Wikipedia - Describes ADC converting continuous analog to discrete digital; includes sampling and quantization. ↩

A DAC converts a digital input code into an analog voltage/current signal.2

Footnotes

  1. Digital-to-Analog Converter - an overview - Defines DAC as transforming numeric codes into an analog signal. ↩

  2. Digital to Analog Converter (DAC) - Types, Working & Applications - States DAC converts digital signals into analog voltage or current. ↩

Which option matches a DAC?

Scores reflect conceptual match to the definition and reverse-function relationship.

Signal-domain direction in a basic mixed-signal chain

Computation / storage

Digital side

A digital system produces an nn-bit word representing a desired analog value."

Digital-to-analog conversion

DAC stage

The DAC maps the code to an analog voltage/current level proportional to the code.2"

Footnotes

  1. Digital-to-Analog Converter - an overview - Defines DAC as transforming numeric codes into an analog signal. ↩

  2. Digital to Analog Converter (DAC) - Types, Working & Applications - States DAC converts digital signals into analog voltage or current. ↩

Analog actuation / sensing path

Physical world

The analog signal drives a load (or is otherwise used) in continuous time."

Analog-to-digital conversion

ADC stage (opposite direction)

If feedback/sensing is needed, an ADC samples and encodes the analog signal into a digital code."

Footnotes

  1. Analog-to-digital converter - Wikipedia - Describes ADC converting continuous analog to discrete digital; includes sampling and quantization. ↩

Common confusion: “reverse functions”

Knowledge Check

Question 1 of 4
Q1Single choice

A DAC performs which conversion?

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