Problems with NX3L4051

[Drops93]

Hi there,

For my bachelor thesis I use the multiplexer NX3L4051. Now I have the problem that I have not taken into account the internal protective circuit. Thus my circuit does not work as intended.

Briefly to the function: I would like to implement a ratiometric resistance measurement. For this I have several reference resistors at the inputs of the NX3L4051 (Y0, Y1,...). These I have connected to a 5V reference voltage, by the internal protection circuit is now a current in my measurement imprinted that I do not want. Could you give me a sketch of the internal circuit, so I can think of a circuit how I can still save my PCB.

And I connect the unknown resistor to GND at the output of the NX3L4051 (output Z) and measure the voltage with an ADC.

Do you have a multiplexer that has the same pin layout but can handle up to 5V at the inputs ?

Thanks a lot

[TomasVaverka]

Hi Jan,

The max recommended supply voltage is 4.3V and the switching voltage should not be higher than VCC.

Back power, voltage swing limited, may happen when Vsw > Vcc, basically due to ESD diode may be turning on.

We do not have any pin compatible multiplexes capable to handle up to 5V at the inputs.

Best regards,

Tomas