32:1 CH Analog mux with 4 Ohm on-state resistance

Muxing signals up to 10MHz with 10kV ESD protection and full DIP-switch manual control.3D 32CH to 1 analog multiplexer MUX ESD protection by Nadim Conti

In a lab, to have a fast analog multiplexer at hand is a must. Most of the time you will rely on attaching and dethatching cables from a DUT to move them around and test it, but with a mux, you can wire everything up and then control it with a simple Arduino script (or in the case of this board, by pressing all those beautiful dip-switches!).

is the IC we’re using. A 4-Ohm on-state 32:1 analog mux that, if properly PCB routed, can let you pass through it signals up to 10Mhz.

Partial schematic Analog mux 32ch to 1 for Arduino or raspberry by Nadim Conti
Partial schematic – Analog mux 32:1

Unfortunately, Analog’s IC is very ESD sensitive, and since it costs 10Euro, it is worth to invest in some kind of protection, namely, a TVS (Transient Voltage Suppressor).

One 82402304 from Würth Elektronik, a  TVS DIODE with 5V nominal voltage and Maximum breakdown at 6.8V, can easily handle this ESD issue by shunting VCC to GND whenever VCC passes 6.8Volts (Caps on the board are rated up to 50V and the MUX can handle only up to 7V).

Everything else on the board is there to either pull up signals (10k general purpose resistors) or to bypass the voltage input (0.1uF and 10uF).

3D - Resistor placement and ESD protection for Analog Mux 32 to 1
Bottom layer, the SOT23-6L package of the TVS can be seen just below the two bypass caps.

Attention, D (Drain) is not bypassed in any way. It is left open to let the user do whatever he wants, but between the IC and Header, a 0R is placed to ease debugging (not present in the 3D model).

DOWNLOAD FULL SCHEMATIC and BOM [PDF]

DOWNLOAD ALTIUM 18 FILES

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