VGA DAC Calculator

Configure the resistor network used for VGA DACs. This tool computes the equivalent resistances and output voltages for each bit combination, estimates channel utilization against the 0.7 V VGA nominal full-scale (with +5% upper limit), and renders the color palette and its RGB color-space distribution.

DAC Model Selection

Circuit Diagram

Resistor Configuration (per channel)

Formulas

Equivalent resistance (both bits = 1):

\[R_{eq} = \frac{R_1 \times R_2}{R_1 + R_2}\]

Output voltage:

\[V_{out} = V_{in} \times \frac{R_L}{R_{eq} + R_L}\]

Global Settings

Voltages per bit combination

Example uses Red channel

B1 (MSB) B0 (LSB) Req Vout

Levels Table (All Channels)

Level (0–3) Bits V Red V Green V Blue Color

Generated Palette

Level: --
Voltage: --
RGB: --

Palette in RGB Color Space

Authorship & License

Copyright (c) 2025 Carlos Venegas <[email protected]>
X: @cavearr | github: @cavearr | FPGAwars: [email protected]
This work is dedicated to the public domain under the Creative Commons
Zero (CC0) 1.0 Universal. To the extent possible under law, the author(s)
have waived all copyright and related or neighboring rights to this work
worldwide. No rights are reserved.
Full text: https://creativecommons.org/publicdomain/zero/1.0/
-- Citing authorship is a personal ethical decision --