TS5A3166 cann't be turned off

Ivan,

I am moving this thread to the logic forum for a quicker response since this part has been supported there in the past.

Thank you,

Adam

Can you explain what you mean by turned off. Is the power for the part turned off or is the switch opened by the control pin.

Also since this is RS485 just wnt to conferm there is not a signal that is negative on the input.

The switch will be open when V+ is 0V. V+ must be 0V in order for the switch to be turned completely off.

  V+ should not float

HI,Chris,

Thank you for your quick reply.

Customer wants to use TS5A3166 to switch the RS485 bus.

They hope to  break the A/B connection to external RS485 bus when not used.

But they found the MCU can not turn off  the analog switch 3166 by pin IN.

Even connect the IN pin directly to GND, there is still signal output from Pin2 COM of TS5A3166.

Can you help explain why the anlaog switch doesn't work?

Regards,

Ivan

The schematic does not show the gnds connected. Are they?

Does the RS485 signal ever go negative?

Hi,Chris,

This is only a diagram for your better understanding the problem.

The power supply is 5V for HVD3082E. A/B bus is tyipically with 0~5V range.

Does the negative signal make the analog switch not work?

Thank you.

Regards,

Ivan

Any signal that goes below gnd more than .5V on a Nchannel FET will turn the switch on.