Accuracy Translator — Analog Intuition

Along the way

One vertical line

Everything on this page is one “accuracy story.” Drag the blue line (or any control) and all the units stay consistent.

Pick a preset or set Bits / Full scale.
Slide the nomograph — one line crosses every scale.
Read ppm, %FS, dB, counts as other ways to say the same thing.
Check LSB size for your full-scale range (volts).

Ideal model. SNR uses 6.02·N + 1.76 (full-scale sine quantization). Real ENOB is often worse — datasheets win.

Translate resolution and full-scale accuracy between the units engineers actually use — bits, ideal SNR (dB), codes, % of FS, ppm, and rough DVM digits — on a classic nomograph.

Presets

Default: 12-bit converter, 4.096 V full scale (common 1 mV/LSB family).

Nomograph

Drag the blue line or use the slider

Line position

Values

Sliders live-update · type a number then Enter or leave the field

DVM digits

ppm (of FS)

Powers of ten

Percent of FS

Bits (N)

Ideal SNR (dB)

Counts (2^N)

Full-scale range (V)

LSB step size From FSR ÷ 2^N

Voltage reference floor

Optional · shows where V_REF drift can limit you

Full-scale is only as good as the reference that defines it. First-order tempco: total drift ≈ (ppm/°C) × ΔT — drawn as an amber V_REF floor on the nomograph. If your blue ADC line is to the right of that floor, the reference (not ideal N-bit quantization) is the limiter.

Show V_REF limit line

Drift (ppm/°C)

ΔT span (°C)

Enable to compare V_REF drift to the blue operating point.

How to use & why it matters

What this tool is

A live version of the classic “accuracy translator” nomograph (same spirit as ADI app notes such as AN-82): one operating point expressed many ways so you can read a datasheet or a system budget without unit thrash.

How the units connect

One operating point, many languages (ideal model):

\[ \underbrace{N}_{\text{bits}} \;\longleftrightarrow\; \underbrace{2^{N}}_{\text{counts}} \]

\[ \mathrm{SNR}_{\mathrm{ideal}} \approx 6.02\,N + 1.76~\mathrm{dB} \quad\text{(FS sine, quantization only)} \]

\[ 1\,\mathrm{LSB\ of\ FS}: \quad \% = \frac{100}{2^{N}}, \qquad \mathrm{ppm} = \frac{10^{6}}{2^{N}} \]

\[ \text{“Powers of ten”} = \log_{10}\!\left(\frac{\varepsilon}{\mathrm{FS}}\right) \]

\[ \text{DVM digits} \approx \frac{N}{3.25} \quad\text{(rule of thumb)} \]

\[ \mathrm{LSB\ size} = \frac{\mathrm{FSR}}{2^{N}} \]

\[ \varepsilon_{\mathrm{Vref}} \approx \left(\frac{\mathrm{ppm}}{^{\circ}\mathrm{C}}\right) \times \Delta T \quad\text{(first-order tempco floor)} \]

Why it matters

Specs jump between “16-bit,” “96 dB,” “15 ppm,” and “0.0015%.” They’re often the same relative full-scale story. This page keeps that map honest for the ideal case so you can sanity-check a claim before you dig into noise, INL, and reference drift.

What it is not

Not measured ENOB, not a full error budget, and not a substitute for SNR/THD plots. Use it to translate language; use the lab and the datasheet to decide if the part is good enough.

Prefer the old layout? Open the classic Accuracy Translator →