How do I use the MUX/DEMUX calculator?

Enter the number of channels, signal bit width, signal frequency, switching time, supply voltage, and load resistance. Click "Calculate" to see the address map, switching animation, and performance metrics.

What does the calculator do?

It simulates a multiplexer or demultiplexer, calculates control lines, throughput, maximum operating frequency, load current, and power consumption, and provides a live animation of channel switching.

What is the difference between MUX and DEMUX?

A multiplexer combines multiple inputs into one output, while a demultiplexer distributes one input to multiple outputs.

How is the maximum operating frequency calculated?

It is estimated using the formula: Max Frequency = 1 / (2 × switching time), considering the switching delay.

Can I simulate both MUX and DEMUX?

Yes, you can switch between MUX and DEMUX modes with a single click, and the diagram updates automatically.

MUX/DEMUX Calculator

Number of channels Signal bit width, bits Signal frequency, MHz Switching time, ns Supply voltage, V Load resistance, Ω

This tool helps you analyze multiplexers and demultiplexers quickly. It calculates key parameters, generates an address map and runs a live animation that cycles through channels so you can see switching behavior at the specified signal rate.

What a MUX and DEMUX do

Multiplexer (MUX) — selects one of several input channels and forwards it to a single output using address lines.
Demultiplexer (DEMUX) — takes one input and routes it to one of many outputs determined by control signals.

Key features

Switch between MUX and DEMUX modes with a single click and update the diagram automatically.
Configure channel count, data bit width, signal frequency, switching delay, supply voltage and load resistance.
Automatic calculation of address/control lines (ceil(log2(N))), data throughput (bits × frequency) and theoretical maximum operating frequency based on delay.
Estimate load current and electrical power for the selected load and supply voltage.
Auto-generated address table for every channel and a step-through animation showing active channel selection.

How to use

Select the operating mode: MUX or DEMUX.
Enter the number of channels (examples: 6, 12, 24), the signal bit width, and the desired signal frequency in MHz.
Set the switching delay in nanoseconds, supply voltage, and load resistance.
Press Calculate to display results and start the animation that cycles channels according to the frequency you entered.

Interpreting results

Address lines — minimum control inputs required: ceil(log2(N)).
Throughput — raw data rate in bits per second (bit width × frequency).
Max. frequency (theory) — approximate upper bound based on switching delay: 1 / (2 × delay).
Load current — estimated I = V / R.
Power — estimated P = V × I (useful for thermal and supply planning).

Quick comparison

Parameter	Multiplexer	Demultiplexer
Purpose	Combine many inputs into one output	Distribute one input to many outputs
Control lines	Select which input is routed	Select which output receives the signal
I/O count	N inputs, 1 output	1 input, N outputs
Typical use	Data bus steering, ADC input selection	Address decoding, signal routing

Multiplexers and demultiplexers are widely used in embedded systems, instrumentation and digital logic. Use them to expand input/output lines on microcontrollers, build time-division multiplexed data buses, and route signals in test setups or communication front-ends.

Example

Suppose you select 12 channels, 2-bit data, 4.5 MHz signal, 30 ns switching delay, 3.3 V supply and a 330 Ω load. The tool will report:

Address lines = ceil(log2(12)) = 4
Throughput = 2 bits × 4.5 MHz = 9 Mbps
Max theoretical freq ≈ 1 / (2 × 30 ns) ≈ 16.67 MHz
Load current ≈ 3.3 / 330 ≈ 10 mA
Power ≈ 3.3 × 0.01 ≈ 33 mW

For reliable operation keep switching frequency well below the theoretical maximum to allow for propagation delays and signal settling. Account for driver strength and bus capacitance when estimating real-world switching limits. When designing for many channels, consider hierarchical multiplexing to simplify address logic and reduce routing complexity.